Back Cover
 Title Page
 Front Matter
 Table of Contents

Group Title: Bulletin of the Florida State Museum
Title: Sea turtles of the Guianas
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00001527/00001
 Material Information
Title: Sea turtles of the Guianas
Series Title: Bulletin of the Florida State Museum
Physical Description: 86-140 p. : illus., map. ; 23 cm.
Language: English
Creator: Pritchard, Peter Charles Howard, 1943-
Publisher: University of Florida
Place of Publication: Gainesville
Publication Date: 1969
Subject: Sea turtles   ( lcsh )
Turtles -- Guyana   ( lcsh )
Turtles -- Suriname   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Bibliography: p. 139-140.
General Note: Cover title.
Statement of Responsibility: by Peter C. H. Pritchard.
 Record Information
Bibliographic ID: UF00001527
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA0837
notis - ACK3566
alephbibnum - 000442915
oclc - 00110436
lccn - 70627438

Table of Contents
        Front page 1
        Page 140
    Back Cover
        Page 141
    Title Page
        Front page 2
    Front Matter
        Front page 3
    Table of Contents
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
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        Page 106
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
        Page 115
        Page 116
        Page 117
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Chavez, H. 1968. Marcado y recapture de individuos de tortuga lora, Lep-
idochelys kempi (Garman). Inst. Nac. Inv. Biol. Pes., Mexico 19:1-28.
Deraniyagala, P.E.P. 1939. The tetrapod reptiles of Caylon. Colombo. 1-xxxii,
Fitter, R. S. R. 1961. The leathery turtle or luth. Oryx, 6 (2): 116-125.
Carman, S. 1884. The reptiles of Bermuda. U.S. Nat. Mus. Bull., 25:285-303.
Geyskes, D. C. 1945 De Visscherij aan de Beneden-Marowijic. Gestenc. uitg.
Landb. Proefstat. Paramariho. (not seen).
Hendrickson, J. R. 1958. The green sea turtle (Chelonia mydas) in Malaya and
Sarawak. Proc. Zool. Soc. London, 130 (4): 455-535.
Hughes, G. R., A. J. Bass and M. T. Mentis. 1967. Further studies of marine
turtles in Tongaland, I and II. Lammergeyer 7, 1-72.
Kappler, J. 1881. Hollandischo Guiana. Vertaling van F. L. Postel, Winterswijk.
(not seen).
Lacepede, Comte. de. 1847. IIistoire Naturelle (new ed.). Paris, Vol. 1.
(not seen).
Lewis, G. B. 1940. The Cayman Islands and marine turtle. Bull. Inst. Jamaica,
2 (appendix): 56-65.
Loveridgc, A. and E. E. Williams. 1957. Revision of the African tortoises and
turtles of the suborder Cryptodira. Bull. Mus. Comp. Zool., 115 (6): 163-557.
Lynn, W. G. and M. C. Ullrich. 1950. Experimental production of shell abnor-
malties in turtles. Copeia, 1950 (4): 253-262.
MacAskie, I. B. and C. R. Forrester. 1962. Pacific leatherback turtles (Dermo-
chelys) off the coast of British Colombia. Copeia, 1962 (3): 646.
Medem, F. J. 1962. Estudio sobre tortugas marinas: Informe sobre la com-
mission realizada en la Costa Atlantica. Corporacion Autonoma Regional de
los Valles del Magdalena y del Sinu, pp. 1-11.
Pope, C. H. 1939. Turtles of the United States and Canada. Alfred Knopf, N.Y.
200 pp.
Pritchard, P. C. H. 1964. Turtles of British Guiana. Proc. British Guiana Mus.
and Zoo, No. 39:19-45.
1966a. Sea turtles of Shell Beach, Guyana. Copeia, 1966 (1): 123-125.
1966b. Occurence of mesoplastra in a Cryptodiran turtle, Lepidochelys
olivacea. Nature, 210: 652.
Schulz, J. P. 1964. Zeeschildpadden, deel II: Zeeschildpadden in Suriname.
Dienst Landsbosbeheer Suriname, Paramaribo. pp. 1-44.
1967. Zeeschildpadden, deel I (2nd. Ed.): Een literatuurstudie. Dienst
Landsbosbeheer Suriname, Paramaribo. pp. 1-79.
Villiers, A. 1958. Tortues et crocodiles de l'Afrique Noire Francaise. Dakar.

Vol. 13

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Volume 13

Number 2


Peter C. H. Pritchard




lished at irregular intervals. Volumes contain about 300 pages and are not
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I 5-q C) 2z-

N/% >

WALTER AUFENBmER, Managing Editor
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Published March 6, 1969

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SYNOPSIS: Summarizes investigations of turtle nesting beaches in Guyana during
August 1964, August 1965, and April 1967, in Surinam during May to July 1966,
May to July 1967, and June-July 1968, and in French Guiana in June and
July 1967. Four species of sea turtles nest on beaches in Guyana, particularly
Shell Beach: Chelonia mydas, Eretmochelys imbricata, Dermochelys coriacea
and Lepidochelys olicacea. The same four species nest in Surinam, although
Eretmochelys does so only rarely. Lepidochelys sometimes forms huge nesting
aggregations at Eilanti, Surinam, and individuals have been shown to nest at
the same place in successive years. Dermochelys, Chelonia, and probably Eret-
mochelys all nest in large numbers in French Guiana, particularly at Silibache
Beach. Survival and conservation of sea turtles in northern South America are


INTRODUCTION ..... ...................... .... .......................-..................... 86

ACKNOWLEDGEMENTS .. ............. ......................... ...... ......... 86

STUvn A RE ................... ...................................................... ........................... 87

M EIt ODS ......... ............ .. .. ........... ..... ........ ......... ...... 88

SPECIES ACCOuNTS ................... ........... ..... ....................... ....... .............. 8 89

Chelonia mydas ............................... ...... .......... ..... 89

Lepidochelys olivacea .... ................. .... .... ....................... ........... 96

Dermochelys coriacea ....-........------... -- ......... ................... 120

Eretm ochelys im bricata ...................................... .................................... 132

Caretta caretta ..- ------- .. .................................... .............................. 136

ECONOsM CS AND THE FL-TUnE ................. ......... ...... ... .. ................... 136

LrrERATURm CiTEn ....- --..... .................................. ............... 139

'The author is a graduate teaching assistant in the Department of Zoology,
University of Florida, Gainesville, where he is working on the biology and
systematics of sea turtles for his Ph.D. degree. Manuscript received 1 September
1968 Ed.

Pritchard, Peter C. H., Sea Turtles of the Guianas. Bull. Florida State Mus.,
vol. 13, No. 2, pp. 85-140.


Early accounts of sea turtles nesting in northeastern South America
mention both Surinam (Kappler, 1881) and Cayenne (Lacepede,
1847). The occurrence of sea turtles in the waters and on the beach-
es of the Guianas was known much earlier than this. A map of Suri-
nam drawn by van Gerard of Keulen in 1670 indicates the area
between Mot Creek and Wia-Wia Creek (now known as Bigi Santi)
as "Schildpad (turtle) Bay". The same name appears on Reimer
Ottens' map of 1740. Other than my own few recent notes (Pritchard,
1964, 1966a and b) and the works of Schultz (1964) and Brongersma
(1968), few modern references to the turtle populations nesting on
this coast exist.

I wish to express my gratitude to the trustees of the Browne Fund
of the Royal Society for a grant-in-aid covering the cost of the 1965
trip to Guyana. I am also most grateful to Hugh Popenoe of the
Department of Tropical Agriculture, University of Florida, for a
generous grant which, in conjunction with a grant from the Centre
for Latin American Studies, financed the 1966 Surinam expedition.
Conservation and scientific work in Surinam and French Guiana in
1967 and 1968 was financed entirely by the World Wildlife Fund.
Many members of the Surinam Forest Service, especially J. P. Schultz,
F. Bubberman,, A. Voorheuven, G. Plak, A. Wolf, and E. Donner,
were of inestimable help during my time in Surinam. My super-
visor of studies, Archie Carr, was of help in many ways, and from
his sources of research support NSF Grant GB 3910; ONR Con-
tract 580 (12) with the University of Florida; Caribbean Conserva-
tion Corporation furnished tagging equipment and funds for tag-
return rewards. The ex-Governor-General of Guyana, H. E. Sir
Richard Luyt, very kindly offered me accommodations and much
assistance in Georgetown. A number of Guyana Government officials,
in particular Mrs. Winifred Gaskin, C. Me. A. Ashley, M. L. Persaud
and D. Shaw, were of invaluable help in different ways. Dennis
Joaquin of the Waini River accompanied me to Shell Beach and took
an active interest in the project. In French Guiana G. Grivaz of the
Forestry Service and Pierre Fourmanoir were exceedingly helpful.
P. W. Kent, my biochemistry supervisor at Oxford, was of great assis-
tance with the original grant application. Archie Carr and David
Ehrenfeld read the manuscript and made helpful criticisms.

Vol. 13


Finally I would like to thank my friends Tom Stubbs, Tom Lesure
and Bill Greenhood who accompanied me on the Surinam expeditions
and cheerfully joined in many hours of beach-walking at times when
normal citizens were asleep.

The detailed studies summarized in this paper were conducted
on three beaches: Shell Beach, Guyana; Bigi Santi, Surinam; and
Eilanti, Surinam.
Shell Beach, North-West District, Guyana- About 6 miles long
and running northwest-southeast, this beach reaches its maximum
width of about 250 yards about 1 mile from the northwestern tip.
It is separated from the mainland by a large mud flat, much of which
is exposed at low tide. The lagoon harbours many four-eyed fish
(Anableps), sawfish (Pristis), and several unidentified species of sharks.
In the open sea are larger sharks, including hammerheads. The most
conspicuous birds of the beach are black vultures, spoonbills, scarlet
ibis, flamingos and egrets. Beach and lagoon both become narrower
southeastward, eventually becoming simply a continuation of the
narrow barrier beach fringing much of the coast of the North-West
Shell Beach is mobile, having apparently moved 4 miles towards
Venezuela in the last 3 years. Piles set in the beach when it was used
as an emergency landing strip in 1939 now stand in the sea between
15 and 20 miles southeast of the beach's present location. The beach
profile is inclined steeply just above the high tide mark. Much of
this higher area is covered with a dense growth of beach morning
glory, but this is sparse on the newly-deposited northwest end of
the beach.
Bigi Santi, Surinam This name is applied to the stretch of beach
between Matapica Creek and Wia-Wia Bank. The section on which
the present study was conducted is about 40 miles east of the mouth

*Some of the more clearly defined separate beaches between Shell Beach and
the Essequibo Mouth have names, e.g. Papaya Beach, Father's Beach, Turtle
Beach. Other beaches in Guyana used by turtles for nesting include Punta
Playa on the Venezuelan border, 63 Beach near the mouth of the Corantijn
River, Mahaica-Mahaicony Beach between Georgetown and the Berbice River,
Suddie Beach on the west bank of the Essequibo, beaches on several of the
Essequibo Islands, e.g. Zeelandia Beach on Wakenaam Island, Dauntless Point
on Leguan Island; there is also an 8-mile stretch of good turtle beach on Tiger



of the Surinam River. For detailed maps of this beach and also of
Eilanti Beach see Schultz (1964). The beach is backed by extensive
swampy areas, but not by open bodies of water. Like Shell Beach,
Bigi Santi is rapidly moving westward. The changing coastline is
exposing large expanses of previously suffocated forest, and the many
dead tree trunks are so rotten that they can be pushed over with
one hand. The beach material is sand and broken shell, in contrast
to that of Shell Beach which is pure shell.
The general aspect of the beach and its concomitant bird and
fish fauna are similar to those of Shell Beach.
Eilanti, Surinam- This is the name given to a small beach at the
tip of a point of land on the west side of the mouth of the wide
Marowijne River, which forms the border between French Guiana
and Surinam. The beach is about 1 mile in length. A great mud
bank has been deposited off the beach, about 1/, mile of which is
exposed at low tide. At one time Eilanti was an island, but silting
has reduced the original break with the mainland to a narrow inlet,
100 yards or so in length, at the west end of the beach. Schultz
(1964) gives maps showing the progressive alteration of the beach.
Lengths referred to in this paper refer to the straight-line shell
length, measured from the nuchal lamina to the rearmost projection
of the carapace. Plastral lengths are median; widths maximum. At
first I measured the turtles with a caliper made from aluminum slats
and a rollup metal tape, later 1 used a steel tree caliper. Weights
were taken by turning the turtle and tying the flippers diagonally
together and attaching a Salter's 10 cwt capacity self-recording dy-
namometer, adjusted for use in a vertical position, to the intersection
of the diagonal cords: a stick passed through the upper ring of the
dynamometer is raised until the turtle is just lifted off the ground.
In this way one man can weigh the largest ridley or hawksbill, but
two or more are needed for a green turtle, and at least six for a
Turtles were tagged with Hasco brand cattle ear-tags clipped
through the inner trailing edge of the front flipper. These tags are
inscribed in Spanish and English, offering a reward for their return
to the University of Florida. The tagging efforts of Carr and his
co-workers at the University of Florida over the last 12 years have
accustomed many of the turtle fishermen of the Caribbean, Gulf of

Vol, 1:


Mexico, and South Atlantic to watch for the tags and to return them
Shell terminology in this paper follows that used by Carr (1952).

Chelonia mydas
The green turtle, locally known as 'bettia', nests at Papaya Beach
where fresh eggs and an adult carapace were seen 29 April 1967, on
Turtle Beach where six shells were seen on the same date, and prob-
ably at Dauntless Point, Leguan Island. According to N. O. Poonai
of the Guyana Museum, nesting also occurs on 63 Beach, Tiger Island
Beach, Suddie Beach, Zcelandia Beach, and Mahaica-Mahaicony
Beach. The most used nesting beach appears to be Shell Beach (also
called Kamwatta Beach) in the North-West District.
Nesting season and periodicity: In 1964 and 1965 visits were
made to Shell Beach in August, which was probably near the peak of
the hawksbill season but well after the green turtle peak; only 11
green turtles nested on Shell Beach between 6 and 27 August 1965.
Arawak turtle hunters, questioned about the peak and extent of green
turtle nesting in Guyana, stated that the earliest appear in March
and continue abundantly through July, with only stragglers there-
after. This was corroborated by a third visit to Shell Beach in April
1967, when at least five or six green turtles, often more, nested each
night. Parties of negroes and Amerindians on the beach were slaugh-
tering virtually every turtle that nested.
One green turtle, tagged while nesting 7 August, nested again
20 August, when it was caught by turtle hunters. This interesting
period of 13 days is of the same order as that at Tortuguero
(M = 12.5 days, Carr & Ogren, 1960), Ascension (M 14.5 days,
Carr & Hirth, 1962), and the Talang Islands off Sarawak (M = 10.5
days, Hendrickson, 1958).

Carapace size and egg dimensions: For dimensions of some green
turtle carapaces measured on Shell Beach see Table 1 and Figure 1.
Six clutches of green turtle eggs from Shell Beach ranged in number
from 106 to 138. Four random normal eggs had the following dimen-
sions (in mm.): 46 x 48; 47 x 49; 46 x 47; 46 x 48; one abnormal egg
measured 56 x 44 mm.



Length Width Length Width
38 30%4 421 29
38%/ 311 42 '/ 32'
383/ 32 42% 32%
40 32 421% 33
4014 29% 42% 33 1
40% 31% 42% 31
41 30% 42y 35
41 32 42% 30%
41 32% 42% 33%
41% 3214 42% 34
411 29% 42% 34%
411 30% 43 33
411/ 31 43 33/2
41 31% 43 33%
41% 32% 43% 29
41% 33 43% 32
41% 33 44% / 324
41% 33 44% 33
41% 30 45 34
42 3214 45% 34
42 32 46 32
42 34

Nesting behavior: Nesting of the green turtle in Guyana was,
as far as could be discerned, identical to that Carr and Giovanolli
(1957) describe for females from Tortuguero. According to Jerome
da Silva, turtles nesting on the populated Essequibo Coast are much
more easily disturbed than those on Shell Beach, where we were able
to watch the whole nesting procedure from the stage of digging the
body pit under continuous flashlight illumination.
Green turtles in both Guyana and Surinam have the habit of
making 'half-moons' (non-nesting exploratory emergences) as they
do at Tortuguero and on other mainland beaches. The rather charm-
ing belief was expressed to me that these half-moons are made by
male turtles in search of a suitable place for their mates to nest.
Trial nest excavation also occurs, a turtle sometimes digging in four
or five places before actually nesting.
Population structure: That the Guyana green turtle population
is composed at least in part of immature individuals is demonstrated
by my receiving third-hand a 7-pound individual with a carapace
measuring 111/" x 91/'", with no other data than 'taken by a trawler
off the Guyana coast' on 28 July. This is about as small as green
turtles are found anywhere, apart from hatchlings on nesting beaches;

Vol. 13




39 40 4 42 43 44 45 4647 4




35 36 37 38 39 40 41 42 43 44 .
Carapace length (inches)
Figure 1. Carapace lengths of mature female green turtles (Chelonia mydas)
from four selected localities; Ascension Island data from field notes
of H. Hirth; Tortuguero data from Carr and Ogren (1960).
it was probably about 1 year old and, as no turtle grass grows in this
area, had probably not yet developed the herbivorous diet of the half-


grown and adult turtles. When I released the turtle, untagged, on the
beach at Georgetown, its seaward orientation had not been disturbed
by several days in a bathtub.

Figure 2. Two types of green turtle skull from shell Beach, Guyana; left: large
bulbous-topped type; right: flat-topped, small type.

Here the local name of the green turtle is "krape". The species
nests fairly abundantly on Bigi Santi and also on the beaches near
and in the mouth of the Marowijne River (Eilanti, Tijger Bank,
Babboon Santi). Nesting occurs on Marowijne beaches far enough
upstream for the water to be fresh or only slightly brackish.
Nesting season and periodicity: On Surinam beaches green tur-
tles nest most abundantly in April and May, but a few stragglers
persist until June or early July. We tagged 30 green turtles at Bigi
Santi between 5 and 14 May, and between 24 May and 6 June 1966;
about 30 more nests were discovered after the turtle returned to the
sea. We tagged 44 more green turtles at Eilanti and Bigi Santi in
May and June 1967. During the 2 months of the peak season an
average of four or five green turtles nest each night at Eilanti. About
this number also nested each night on Bigi Santi during the 1966
season, but in 1967 considerably more, occasionally up to 15 or more
per night, and in 1968 sometimes many more than this. The follow-

Vol. 13


ing individual interesting intervals (in days) were recorded: 13, 13,
13, 15, 16, 21, 28, 29. Except for the 21 day record, these are com-
mensurate with the average interncsting period of other areas, 13
to 14 days.
Size of mature females: Surinam green turtles are unusually
large (Table 2); the average length of 60 mature females was 44.02",
nearly 2 inches longer than the average of the Ascension Island
colony, previously thought to be the largest. Lengths ranged from
391/2 to 48 inches, and weights from 266 to 493 pounds. The only
male measured had a carapace 43" long and 321/4" wide.
Evidence of migration: Only one tagged green turtle from Suri-
nam has been recovered to date, a 45-inch individual which was

Carapace Carapace Plastron Head Weight
length width length width (Lbs.)
39% 31% 33 5% 312
41/2 31% 33% 6 329
41% 32 34 51/ -
41% 33% 32 6 344
42% 321% 35% 6% 340
42%/ 32/2 34% 6 286
42% 331 34% 5% 350
43 32 34 5% 266
43 36 341 5%1/ 330
431 34% 5% -
43% 341 37 6 355
44 331 351 6 379
44 34 32% 5% -
44 34% 5% -
44% 331 34 5% 405
441 34 341 6 359
44% 36 36 6 394
44% 34 361/ 6 462
45 35 35%4 6% 450
45 34% 6
45 35% 37 6 -
4514 33 36 6 399
4514 34%/ 36 6 417
45%3 351 37 6/ 392
45% 35% 36 6 -
46 34 371'/ 6 462
461 34 3614 5% 396
46% 343 6
47 331 36% 6
471/ 34 34% 6 392
48 37 39% 61 493


found, only 6 weeks after tagging at Bigi Santi, near Siao Luis on the
coast of Brazil (Figure 3). This journey represents a swim of at
least 1000 miles against the prevailing current. It will be interesting
to see if more returns confirm this as a regular migration route. This
is the first known case of a migrating turtle crossing the Equator.

0J N


55W 500W 45 W

0W 55eW 50 W 45W
Figure 3. Recovery of tagged turtles: 1: Eretmochelys imbricata "... i it Shell
Beach; 2: Lepidochelys olicacea tagged at Eilanti; 3: C mydas
tagged at Bigi Santi (Arrows do not indicate actual routes traveled).

Some of the green turtles at Bigi Santi have rather large barnacles
on the carapace; green turtles in other areas remain almost free of
barnacles throughout life, although hawksbills and loggerheads are
often encrusted with them. The ridleys examined had only occasional
small barnacles on the head and shell, while leatherbacks were in-
variably free of them.
Clutch sizes and incubation periods: Average number of eggs in
20 green turtle nests from Bigi Santi was 142.8 (range 87-174); aver-
age for 248 nests at Eilanti and a small neighboring beach (Dapp
Island) was 141.9, the largest number in one nest being 226. This
number was rechecked, and is apparently the largest number of eggs

Vol. 13


known to have been laid by any sea turtle, or indeed any amniote
vertebrate, at one time. The average number of eggs per nest at
Tortuguero is 110.0; at Ascension, 115.5; at the Sarawak Turtle
Islands, 104.7 (Carr and Hirth, 1962). In all cases samples were
large enough for the difference in average clutch size to be highly
G. Plak gave me the following records of incubation time (in
days) for 40 undisturbed green turtle nests: 47, 52, 54, 55, 55, 55, 55,
55, 56, 56, 57, 57, 57, 57, 58, 58, 58, 58, 59, 59, 59, 59, 59, 59, 60, 60, 60,
60, 60, 60, 60, 60, 61, 61, 61, 61, 62, 63, 64, 64 (M 58.25 days).
The only definite information on fertility percentage is that a clutch of
169 eggs produced 162 viable hatchlings, 2 slow-developing embryos,
and 5 infertile eggs (i.e. 97 per cent fertility). Mr. Plak informs me
that such percentages are normal for clutches on Bigi Santi where
nests are not moved to protected sites after laying. Previously re-
corded average fertility rates are around 50 per cent (Carr and Hirth,
1962), but such data have always involved transferred nests. Their
statement that 'removal of eggs from the nest and installation in
artificial nests impose no additional mortality' is probably incorrect.
Hendrickson (1958) tried to demonstrate that transfer of eggs imposed
no additional mortality by transferring control clutches very carefully
and other clutches rather roughly, but probably any moving of the eggs
after they are laid will lower the hatching percentage.
The hatchlings from one nest of 169 eggs ranged in carapace
length from 51 to 55 mm (M = 5.35 mm; cf 5.17 at Ascension, 4.97
at Tortuguero).
Abnormal green turtle eggs were rare, but one clutch contained
a single large elongate egg and another contained four dumbell-
shaped eggs.
According to Mr. Plak, green turtles occasionally nest by day-
light on Bigi Santi; he had seen emergences at 2:30 PM and at
4:30 PM. Medem (1962) reports a nesting emergence by this species
at 10 AM in Colombia.
I once saw green turtles mating at Bigi Santi; at 5 PM on 14 May
a pair about 60 yards off the beach remained embraced for at least
an hour, but I saw neither the start nor the finish.
Population structure: Green turtles intermediate in size between
hatchling and adult are rarely seen in Surinam, but Schultz (1967)
figures a 35 cmi specimen taken near the mouth of the Surinam River,
and Brongersma (1968) mentions specimens measuring 28.8 and
37.9 cm respectively from the vicinity of the mouth of the Surinam



River, now in the Museum at Leiden (RMNH 13934 and 13935).
According to Lacepede (1847) green turtles used to nest in the
vicinity of Cayenne between April and June; at the end of the 18th.
century about 300 adults were taken there each year. They probably
still nest on several beaches on the lie de Cayenne, in particular Mon-
tabo Beach, Bourda Beach, and Montjoly Beach, judging by my in-
terviews with the local people in 1967, although my informants were
not very definite as to species. Green turtles are also said to nest on
the beach near the mouth of the Mana River, and an aerial recon-
naissance of this area in July 1968 showed that, although most of the
nesting is unquestionably by leatherbacks, some green turtles also
nest here. We could find no evidence of any turtle-nesting on the fine
beach at Kourou. The best beach in French Guiana for green turtles
is Silebache Beach, a few miles west of the mouth of the Organabo
River; it consists of extensive steep-sloping sandy stretches separated
by huge deposits of hard, black mud. Mud flats exposed at low tide,
similar to those at Eilanti Beach, Surinam, force the turtles to nest by
mid- or high tide. I reconnoitered this beach in early June 1967 in
the daytime and over a low tide period at night. Fresh tracks and
nests of both green turtles and leatherbacks were plentiful, and it
seems certain that at least several dozen green turtles nest on this
3-mile beach nightly at the peak of the season. I tagged one green
turtle with a 451/2 inch carapace that was nesting despite the low tide.

Lepidochelys olivacea
The ridley turtle of the Guianas has been a curiously neglected
and persistently misidentified animal. Almost a century ago Kappler
(1881) wrote: (quoted in translation from Schultz 1964) "In May
and June a smaller turtle, weighing about 60-70 Ibs, comes on shore
in such numbers (near the Marowijne River) that on some nights
about thirty can be caught. The Indians call them warana (Chelonia
corticata). These turtles come on shore not only to lay their eggs;
but still I never saw a male on land. The eggs are smaller than those
of the former (i.e. Chelonia mydas), better to eat, and with yellower
yolks. The meat is not so good, and is not eaten." The name Chelonia
corticata Strauch 1862 is customarily synonymized with Caretta
caretta, but Kappler's statement that the breeding size of the animal
is 60-70 lbs identifies the genus Lepidochelys unequivocally. As late
as 1957 Carr summarized evidence for the occurance of Lepidochelys

Vol. 13


olivacea in the West Atlantic as a single adult from Gibara, Cuba,
and rumors of the occasional capture of a turtle fitting the description
of a ridley in Trinidad. Brongersma (1961) wrote that it is "likely
that the species breeds somewhere in the Guianas, and indeed a
further search along these coasts may yield interesting results." As
proof of this, he records a hatchling collected in 1911 in Surinam, and
he received one himself from a fisherman in Surinam in 1963 (Bron-
gersma 1968). Even Schulz (1964) in his excellent and detailed
account of the sea turtles in Surinam misidentifies Lepidochelys as
Caretta (the true identity of the turtles is evident from the photo-
graphs). That same year 1 (Pritchard, 1964) was able definitely to
associate the name Lepidochelys olivacea with a breeding population
of turtles in the West Atlantic.
The ridley nests in reasonable numbers on Shell Beach, where it
is known as "tcracai" (a name used for Podocnemis in Colombia), and
also as "parrot-beak", "roach-turtle", and "hawksbill." It probably also
nests on Waini Beach, Turtle Beach, and Dauntless Point, Leguan
I found 14 ridley shells on Shell Beach in August 1964, most of
them reasonably intact, and 21 more in August 1965. Small turtles
such as ridleys are frequently removed alive by turtle hunters, and
probably many more nest without molestation. Therefore Shell Beach
seems to be a site of considerable ridley nesting activity. The peak
of the season probably lies in May and June; in August very little
nesting occurred. Only three live animals were seen during the
3-week observation period. Turtle hunters caught two of these, while
I tagged and released the third after watching it nest. Egg diameters
on Shell Beach ranged from 39 to 40 mm; those of the hawksbill were
similar (36-40 mm), but hawksbill eggs could be distinguished by the
slight pinkish tinge showing through the shell.
The local name in Surinam is "warana". The species nests in
moderate numbers on Bigi Santi; Schulz (1964) recorded 97 nesting
emergences there between 29 April and 17 August 1964. Few ridleys
nest in April and May when the leatherbacks and green turtles are
nesting in numbers, but more do so in June and July. Between 5
May and 6 June 1966, we found only six ridleys on Bigi Santi. The
first of these, an unusually heavy specimen (97 Ibs) with a 271/
inch carapace, emerged from the sea at 5 PM on 10 May and carried



out its complete nesting process in daylight. Another daytime nest-
ing record for this species is by Caldwell and Casebeer (1964), who
found a ridley emerging in mid-afternoon on the Pacific Coast of
Costa Rica.
Aggregated emergences:-At Bigi Santi I was informed that the
ridley nested in large numbers on certain days in June and July on

Figure 4. A substantial number of the ridleys nesting at Eilanti had shells and
limbs damaged, presumably by shark bites. The raw stump of the hind
foot of the lower turtle suggests that even adult turtles are vulnerable
to shark attacks.


a small beach called Eilanti, near the mouth of the Marowijne River
on the French Guiana border. On a routine visit to the area Mr.
Plak questioned the natives about this and learned that the first big

; "^ w*-,',

Figure 5. General aspect of beach at Eilanti, Surinam. Note the Indian encamp-
ments and the black vultures that eat any eggs the Indians break

Figure 6. Eilanti Beach, 8 June 1966. Note the tracks made by some of the
500 turtles that nested the night before.


,- S

Figure 7. Congestion of ridleys on Eilanti Beach. In the lower picture one
turtle crawls back toward the sea over the carapace of another; it was
restrained in that position until the camera was made ready.

arrival of ridleys was expected 10 June. Accordingly we arrived at
Eilanti a few days early, on 7 June, in the late afternoon, to find
many Indians encamped on the beach, all certain that the big group
of ridleys would come up that night.
The first turtle emerged with the rising tide by daylight at 5:30
PM. Two more came out before dusk, and after the sun went down

Vol. 13


they began to come ashore in large numbers. Nearly all the nesting
was confined to a stretch about 230 yards long at the eastern end
of the /-mile beach. By 10:50 PM we had tagged 133 turtles and
exhausted our supply of tags. At 11:10 PM 97 turtles were nesting
simultaneously on a 230-yard stretch, and 115 turtles were present on
the entire beach. By 11:45 PM only six turtles were left. By mid-
night no turtles remained on the beach, and the falling tide exposed
extensive mud flats, about 1/2 mile wide, crossed by the tracks of
many turtles returning to sea in only a few inches of water. We
estimated at least 400 turtles nested during the night. About 6 AM
the next morning we found 16 more turtles nesting by the early
morning light; 2 hours later one turtle was still pounding down the
sand on its nest site on a very small beach just southwest of Eilanti,
on which possibly as many as 100 ridleys had nested during the
night. The following night (8 June) the first turtle was found nest-
ing at 6:40 PM. At 7:30 there was again only one turtle on the
beach, but at 10:00 PM 26 were nesting, and at 11:30 PM we found
37. An estimated total of between 80 and 100 turtles nested that
night. On the night of 9 June we found four nesting at 7:45 PM,
and 84 at 1:05 AM. The total for the night was probably near 300.
Though we had to leave the beach the following day, we sub-
sequently learned that after 9 June nesting declined to fewer than

Figure 8. Eight mounds of eggs each of this size were accumulated during the
night of 7 June at Eilanti.


15 per night. We did not witness the next big arrival that took place
24 June, but I was told that the numbers were comparable to those
of 7 June. Only three turtles tagged on 7 June were reported in
the later nesting period.
The last major aggregation of the year was expected on 14 July.
We arrived at Eilanti 12 July, but learned that the big group had
nested on the 10th, and that not a single turtle had nested on 11
July. About 10 ridleys nested the night of 12 July, and also a 64-
inch leatherback, but the following night only two ridleys nested.
The next day we left the beach.

Table 3. NUMBERS OF Lepidochelys olivacea NESTING EACH NIGHT DURING

15 May
1 June


24 Junt
1 July

In 1967 we carried out a more protracted study of ridley nesting
at Eilanti; Table 3 shows the numbers of turtles nesting each night.
These accurate figures were made possible by the cooperation of
the Carib Indians of Christiaan Kondre village on the Marowijne
River; each man occupied a few yards of the beach each night,
marked all nests as they were made, and brought the eggs to our
camp in the morning, where we bought them and re-buried them in
an artificial hatchery.
The Indians told me that the 1967 nesting was more diffuse than
normal, and the periods of aggregated nesting occupied several days
each instead of one or two days. Nevertheless a fairly well defined

Vol. 13


periodicity is evident, with peaks of nesting at approximately 14-day
intervals. Thus the mid-point of the first small wave on 30 May was
followed by a major aggregation centering on 13 June, another on
27 June, another on 11 July, and a small, tail-end peak centering
around 25 July. It was noticeable that, even when a large group of
turtles was expected, none materialized unless the wind was fairly
strong onshore. A big group was expected 12 June, but there was
no wind at all that night and relatively few turtles nested; these few
were abnormally skittish and were easily frightened back into the
sea. On the other hand, during a night of intensive nesting activity
turtles could sometimes be tagged as they came out of the water;
after a momentary flinching as the tag perforated the flesh, they
continued up the beach and nested normally.
On all nights of aggregated nesting in 1967, the tide was rising
at dusk and falling at midnight. It was not unusual for one or two
turtles to nest before dark, and moderate nesting took place until
high tide was reached, but the turtles did not emerge en masse until
much later, and indeed many were so late returning to the sea that
they had to struggle through /2 mile of 2-inch deep water over the
mud flat.
Interesting intervals (in days) are shown in Table 4. It may

Table 4. INTERESTING INTERVALS (IN DAYS) Fon Lepidochelys olivacea AT

Interval Frequency Interval Frequency Interval Frequency
1 19 21 6 41 0
2 7 22 6 42 0
3 5 23 4 43 2
4 3 24 1 44 2
5 6 25 22 45 1
6 3 26 9 46 0
7 1 27 15 47 1
8 0 28 17 48 0
9 0 29 17 49 0
10 0 30 68 50 1
11 4 31 14 51 0
12 4 32 3 52 0
13 4 33 12 53 0
14 11 34 5 54 0
15 6 35 2 55 0
16 12 36 0 56 0
17 41 37 1 57 0
18 23 38 0 58 0
19 18 39 0 59 0
20 10 40 2 60 1


be seen that the most usual intervals occur around 17, 30, and pos-
sibly 44 days, with a lone recovery after 60 days. Our immediate
conclusion that the 30-day renesters had merely been missed the
second time, and recorded the first and third times, is not supported
by the small number of turtles found three times. Altogether 1060
turtles were tagged, of which 389 were found nesting twice in the
same season, but only 11 were found three times (except for a few
cases in which one of the intervals was less than 7 days, when we
assume that the turtle did not nest on its first appearance). These
eleven nested at the following intervals (in days): 20 & 11; 12 & 17;
12 & 30; 17 & 16; 17, 3 & 28; 18 & 19; 11 & 19; 17 & 16; 17 & 16;
18 & 16; 14 & 16.
It seems most likely that Lepidochelys olivacea normally nests
twice in a season, at intervals controlled more by external factors
(tide and weather) than by the internal factors that seem to control
the green turtle's nesting.
A particularly interesting finding was that no less than 39 of the
130 turtles tagged 7 June 1966 renested in 1967 between 31 May
and 12 July, and 59, including 28 of the 39 from 1967, renested in
1968. Nine of these nested twice in 1967, on the following dates: 30
May and 28 June; 3 June and 9 June (presumably disturbed the
first time); 11 June and 11 July (three individuals); 13 June and 9
July; 13 June and 11 July (two individuals); 14 June and July 10.
I have since heard from Rene Marquez that Lepidochelys kempi also
sometimes nests in successive years, and recently these results have
been published (Chavez, 1968). On rare occasions Caretta caretta
may nest in successive years on the coast of Natal (Hughes et al,
The local Carib Indians can predict with reasonable accuracy
when large nesting aggregations of turtles are expected, and many
of them move down to the beach to collect the eggs for the market.
The village headman told me that he had been coming to Eilanti
to raid ridley nests for 50 years, and that the numbers did not seem
to be reduced from former times. This is hard to understand, as I
estimated that fewer than 10% of nests on nights of aggregated
nesting remained intact, and relatively few individuals nest on other
nights. Possibly most of the turtles nesting today are old individuals
hatched before systematic nest raiding began. Killing sea turtles
is forbidden by Surinam Law, and indeed the Indians showed a
solicitous regard for them and feared that I might damage or pos-

Vol. 13


sibly kill them by leaving them on their backs overnight to photo-
graph in the morning.
One of the ridleys tagged 7 June 1966 was recovered 17 Sep-
tember 1966 near Cape Cassipore, Brazil, by a shrimp trawler. The
turtle was taken in water 35 fathoms deep, having traveled about
300 miles upstream. Another was recovered 75 miles offshore from
Paramaribo on 20 January 1967. Three of the 1967 group have been
recovered, one from near the Orinoco Mouth, one off the coast of
Surinam, and one from Brazil between the mouths of the Oyapoque
and the Amazon (see Figure 3).
Nesting process. Several writers have hinted at the possibility
that Lepidochelys olivacea makes massed nesting emergences on
Pacific shores of the Americas. Carr (1961) found the apparent
scarcity of nesting ridleys on the Pacific coast of Mexico hard to
reconcile with the large numbers of sexually mature individuals
seen offshore, and concluded that they must be grouping up to nest
in some remote, overlooked place. Caldwell (1966) mentions un-
corroborated reports of large numbers of turtles nesting in the
vicinity of Bahia Banderas, Jalisco, Mexico. Proof of aggregated
nesting by the ridley of the East Pacific was not forthcoming until
late 1967, when Carr received photographs from Antonio Montoya
showing huge numbers of ridleys nesting together on a few kilometers
of beach in northern Gucrrero, Mexico. Montoya estimated that on
one occasion 15,000 turtles nested in a 24-hour period, and on another
occasion 30,000 nested in 18 hours. Nesting thus took place both by
daylight, as is almost invariable with L. kempi, and by night, as is
normal with Surinam L. olivacea. Similar large aggregations have
since been found on the coasts of Jalisco and Oaxaca.
Two questions arise: how do the turtles manage to synchronize
and localize their nesting in this fashion, and why do they do it?
The first question touches upon the larger and as yet unsolved prob-
lems of sea turtle navigation, discussed at length by Carr (1964,
1967). The problem of synchronization of nesting, peculiar to the
genus Lepidochelys, has yet to be discussed in the literature. It seems
unlikely that eggs ripen within the body of the gravid female ridley
in such perfect synchrony that the urge to lay, brought about by pres-
sure of eggs from within, comes upon the whole population simul-
taneously. It is more likely that the eggs ripen in approximate but
not perfect synchrony, and that the female can hold the shelled eggs
for a reasonably long period until the right combination of tide,
moon, and wind brings about an independent urge to lay in all the


local turtles simultaneously. This theory must be viewed in the light
of the common observation that a turtle frightened back to the sea
before it nests will usually try to nest again either later the same
night or the following night. It seems likely that, once a turtle
comes voluntarily from the sea to nest, the eggs start moving towards
the cloaca and produce a pressure that can be relieved only by laying
the entire clutch. If the turtle has not yet tried to leave the sea,
apparently the eggs may be held much longer.
The advantage of massed nesting (arribada formation) is simi-
larly not obvious; some benefit must be gained, as the arribada is a
highly organized trait, certainly not the result of random chance,
and must require constant selective pressure to maintain. One of
the reasons most commonly given is to overwhelm predators, par-
ticularly predators on the eggs and hatchlings, with such a bewilder-
ing abundance of prey, available for such a short time, that even
though the predators eat all they can, large numbers will still sur-
vive. It has now been shown that arribadas in Surinam, Tamaulipas
(Carr 1963) and Guerrero all take place only during strong onshore
winds and, even in Honduras where arribrda formation is yet to be
demonstrated, more turtles nest on windy nights than on calm nights.
This too must have a reason, and it has been suggested that strong
winds may in some way help the turtles to "ride the waves" and be
speeded on to the beach. Much more likely to me is the fact that
a strong wind will help cover up the tracks and nests of the ridley
and thus render them less conspicuous. Little short of a tornado
will obliterate the tracks of a green turtle or leatherback, but the
track of a ridley is so shallow that wind-blown sand can erase it
quickly. William Greenhood has suggested that a strong wind helps
to dislodge the mosquitoes that descend in clouds upon ridleys nest-
ing in Surinam, and this reason too may have some substance.
As no detailed account of the nesting of Lepidochelys olivacea
in the Atlantic has been published, the following description of the
nesting process of an Eilanti individual may be of interest.
The turtle, found crawling up the beach with its carapace still
wet, paused occasionally as she walked straight to the vegetation line,
turned back a short way, and immediately began digging the body
pit. Using rather disorganized strokes of all four flippers, the front
ones usually working together (Figure 9), the rear ones alternately,
she completed the pit in 4 minutes. She started digging the nest
cavity at the rear of the body pit with great energy, but soon be-
came rather sluggish. Her shell moved from side to side through

Vol. 18


Figure 9. Ridley digging body pit with simultaneous strokes

of the front flippers.

a wide angle as she dipped her flippers alternately in the cavity.
She jerked each flipper forward sharply before re-inserting it in the
hole. As the cavity deepened her shell dipped lower to let the
flipper scrape sand off the bottom. At first she moved the rear part
of her carapace in a simple down-up movement, but towards the

Figure 10. Position of ridley during oviposition. Note the fore-flippers anchored
in the sand and the widely-spaced hind flippers.


end of the excavation this movement became a little more compli-
cated; she lowered the rear part of her shell to the full extent, the
front of the shell raised high on the forelimbs and the neck lowered;
then she raised the rear a little, lowered it the same amount, and
finally raised it fully before switching to the other flipper. When
the egg cavity reached its final flask shape, she continued to jerk
the flipper sharply forward as if about to re-insert it in the cavity,
but instead she merely curled the flipper and drew it under the
overhanging rear margin of the carapace. There was no obvious
reason for this movement, which she made about three times with
each flipper.
Oviposition commenced with the foreflippers still braced in the
sand and the hind flippers splayed outwards (Figure 10). The
sequence of movements preceding each deposition of one, two, three,
or four eggs was as follows: 1) humeral region drawn slightly in-
wards and head simultaneously slightly extended, 2) above move-

Figure 11. As the eggs are laid the rear margin of the hind flippers curls

Vol. 13


ments reversed, 3) rear part of shell moved up and down through
a few millimeters with rear margins of hind flippers raised simultan-
eously (Figure 11), 4) eggs deposited. From time to time during
oviposition she raised her head considerably and took a deep breath.
About a minute after laying the last egg, she pulled sand into the
egg cavity by alternate movement of the hind flippers. As soon as
the hole was filled she pounded the loose sand down with alternate
sides of the carapace. During this movement she braced her front
flippers in the sand with her head pointed down and almost resting
on the sand but providing no anchorage. She thumped down the side
of her carapace and the hind flipper on the same side almost simul-
taneously (Figure 12). After a few minutes she stopped pounding

..... ...... .... .....

a ,.- .4

Figure 12. The sand over the nest site is pounded down with side-to-side
movements of the shell; the turtle has just tilted sharply to the left,
compressing the sand with the shell margin.

and with the hind flippers drew more sand into a small pile under
the rear of her carapace. She then resumed thumping, always with
a side-to-side rocking movement, never with the whole plastron. Then
she began to throw sand backwards with one foreflipper and the
opposite hind flipper (Figure 13). This movement generated a slight
turning effect and a slight motion away from the nest site. After four
or five swipes she counteracted the turning movement with a single
quick step and repeated the maneuver with the opposite flippers. This


W. It~ w
t&%.i- -
I 1,

-, -..&.*t C

Figure 13. Sand is swept over the nest site with strokes of one foreflipper acting
in conjunction with the opposite hind flipper.

continued for a long time, while she moved about 5 feet away, then
turned round and returned toward the nest, possibly disoriented by
the light. Into this movement she interposed a few simultaneous
swipes of her fore flippers. Gradually the movement became the stand-
ard walking which carried her part way to the sea. Shortly before she
reached the sea she turned a tight circle and thereafter seemed
completely disoriented, again possibly by the flashlight. Eventually
it was necessary to help her into the sea.
I timed another turtle as she went through the same motions as
1:24 AM Emerged from sea.
1:26 Selected nest site and started body pit.
1:30 Started excavating nest cavity.
1:45 Changed digging movement to flipper-curling move-
ment (see above).
1:46 Starting ovipositing.
1:55 Began to fill egg cavity.
1:56 Commenced sand pounding.
2:00 First front flipper movement.
2:09 Started moving towards sea.
2:10 Reached sea.

Vol. 13



o I-

25 26 27 28 29
Figure 14. Overall carapace lengths of mature female ridley turtles (Lepidochelys
olivacea) from Shell Beach, Guyana; Bigi Santi, Surinam; and Eilanti,

Although the Indians warned me that a flashlight would disturb
the turtles, I found them remarkably oblivious to disturbances of
this or other kinds, even before they had begun to nest. The whole
process from emergence to reentry seemed completely automatic.
Impatient Indians frequently dragged the turtle away from the nest
as soon as the last egg was laid; the turtle went through the cover-
ing-up and sand-pounding motions as if it had not been removed.
Carapace measurements. Mature female ridleys fall in a rather
narrow size range, the vast majority having a carapace length
between 26 and 28 inches. The smallest of 241 individuals measured
had a carapace length of 24.5, the largest 29.125 inches. Figure 14
shows the carapace length distribution for 120 random adult female
ridleys; Table 5 gives more detailed measurements for 21 individuals.
Carr (1952) found the carapace length of mature female Lepido-
chelys olivacea from Pacific Honduras to range from 25.4 to 27.2
inches. My own studies in this area show that some females reach
maturity at as little as 23 inches, while the largest of 100 individuals
measured was 29.5 inches, which is larger than any known from
Surinam. The species may reach a slightly larger size in the Indian
Ocean than elsewhere; the record for the species is apparently held
by a 31.1 inch Ceylon female (.Deraniyagala, 1939).
Clutch size.- Clutch size for 928 Surinam ridley nests ranged
from 30 to 168 eggs; average was 116.072 eggs per nest, and only 4

. 1969




26 *

o *o* *

S25- 0 0

0 0*

o o

24- 2 27 2*8 2

Figure 15. Carapace width plotted against carapace length for 59 mature female
Lepidochely, olivacea fromn Guyana and Surinam and 5 mature female
Lepidochelys kempi from the Gulf of Mexico. Closed circles: L.
olivaLea; open circles: L. kempi.

nests contained less than 70 eggs, and only 4 more than 155. No
data are available for Surinam ridleys for correlating shell length
with clutch size, but out of 45 randoin Honduras ridleys the 20 that
exceeded 26.25 inches in carapace length laid on average 123.8 eggs,
while the remaining 25 turtles averaged only 95.9 eggs each.

Carapace laminae. Lepidochelys olivacea is unique among living
turtles in showing a striking polymorphism of the carapace laminae.
The lateral laminae average about 7 on each side, but vary from
10 to 18 or more for both sides. The central laminate also vary from
23. 0


24 25 26 27 28 29


Figure 15. Carapace width plottugd against carapato e length for 59 mature femaleation
between high central counts and higuyana lateral counts (Figure 16).female
Lepidochelys kempi from the Gulf of Mexico. Closed circles: L.
olivacea; open circles: L. kempi.

nests contained less than 70 eggs, and only 4 more than 155. No
data are available for Surinam ridleys for correlating shell length
with clutch size, but out of 45 random Honduras ridleys the 20 that
exceeded 26.25 inches in carapace length laid on average 123.8 eggs,
while the remaining 25 turtles averaged only 95.9 eggs each.
Carapace laminate. Lepidochelys olivacea is unique among living
turtles in showing a striking polymorphism of the carapace laminae.
The lateral laminae average about 7 on each side, but vary from
10 to 18 or more for both sides. The central laminate also vary from
5 to 9 in number, although there seems to be only slight correlation
between high central counts and high lateral counts (Figure 16).

Vol. 13


Carapace Carapace
length width
251/ 23
26 24/4
261/4 231/4
261 23%
26% 28%
261/, 221/4
261/ 23
26% 231/2
27 23%/2
27 24
27 241/4
27 24%
271A 23
271 241/
271/ 24%
271/2 23%
271/2 24 4
27%/2 24 /2
271/ 251/
28 24 /
28 25'
281 233/

FEMALE Lepidochelys olivacea FnoM

20 Y
20 4
21 4







*All weights taken after oviposition.

The marginals are reasonably constant at 12 on each side. The
plastral laminae are much more stable than those of the carapace,
but the intergular scute may be absent, single, or double.
The lateral laminac of Lepidochelys olivacea are clearly divisible
into whole laminue and half laminac, the whole laminae being homo-
logous to the five laterals of L. kempi. Displacement of the homo-
logues of the seams of L. kempi is usually slight, though in cases
of extreme splitting to 8 or 9 laterals the seams become displaced
to lessen the size of the small first lateral and the large last central.
In almost every case division took place in the rearmost laterals;
for example a 6-6 count is produced by division of the 5th laterals
on each side, or an 8-8 count by division of laterals 3, 4, and 5. One
exception is a shell with a 7-6 count in which only lateral 4 on the
right hand side was divided. It seems impossible to rationalize this
multiscutate condition in terms of function; the extra seams in no
way alter the hydrodynamic form of the animal, and the laminae
are so thin that their precise arrangement could have no effect on
the overall strength of the carapace. Nor could it have any signifi-
cant disruptive or other effect on the animal's appearance, as one


8 9 20 7

9 8 7 3


5 3 6 4 1 2

II 12 13 14 15 16 17

Figure 16. Number of central laminac plotted against total number of lateral
laminae for 88 sibling hatchlillg Lepidochelys olivacea from Bigi
Santi, Surinam.

usually has to look very closely at adult ridleys to see the lamina
boundaries at all (Figure 19).
Carr (1957) suggests that the number of lateral laminae in
Lepidochelys olivacea is geographically correlated. The present data
suggest that this may be true on a broad, statistical basis, but cer-
tainly no more than this (Figure 17). It is nonetheless interesting
to compare the frequency of occurrence of turtles with only five
lateral scutes on each side in the Surinam and East Pacific popula-
tions. This lamina count is of course the normal (and very stable)
one for the Atlantic ridley, Lepidochelys kempi and is the feature
most commonly used for distinguishing the species. The only speci-
mens of L. olivacea with this count mentioned in the literature are
two sibling hatchlings from the Cameroons (Loveridge and Williams,
1957) and 3 out of 378 Ceylonese specimens (Deraniyagala, 1939).
Also an adult ridley shell from the Pacific coast of Mexico (Chiapas)
in the Chicago Natural History Museum las only five laterals on
each side. In Surinam this low count was found to be rare indeed,

Vol. 13


8 9 10 11 12 13 14 15 16 17 18

8 9 10 11

15 16 17 IS

S'9 10 II 12 13 14 15 16 17 18
Figure 17. Histogram showing the lack of correlation of total number of lateral
laminac of Lepidochelys olivacea with locality; A: miscellaneous
West African localities (data from Carr, 1957); B: Shell Beach,
Guyana; C: Eilanti, Surinam; D: Ceylon (Data from Deraniyagala,

shown by only 3 out of 762 individuals, but approximately 1 out of
5 adult Honduras ridleys had five laterals on each side, and one
group of 126 hatcllings included 26 5-5 counts.
Deraniyagala (1939) writes that a low average lamina count is
a tendency of certain broods of hatchlings. This seems borne out







9 10 11 12 13 14 15 16 17 IB




9 10 11 12 13 14 15 16 17 18

Figure 18. Histogram showing variation in total lateral lamina counts within two
complete clutches ot Lepidochelys olivacea fiom Big Santi, Surinam.

by an analysis of three clutches of hatchlings from Isla de Ratones,
Honduras, shown in Table 6, which were not hatched under natural
conditions: brood I was hatched in Florida after the eggs had been
brought back by car, and broods 2 and 3 were hatched in artificial
nests 20 miles from the place of deposition. The extreme counts
shown by broods 1 and 3 could well have been produced by trans-
porting the eggs. Lynn and U11rich (1950) produced hatchlings
Chrysemys and Chelydra with similar abnormalities experimentally
by subjecting the eggs to suboptimal moisture conditions.
The central laminae of L. olivacea show a variation in number
in the same way as the laterals; of 474 Surinam specimens 72 had 5
centrals, 200 had 6, 185 had 7, 16 had 8, and 1 had 9. The marginal
are less variable, about 90 per cent of specimens having 12 on each
side (not counting the paired supracaudals); other counts recorded

Vol. 13


Figure 19. Adult Lepidochelys olivacea from Eilanti, Surinam, showing the
indistinct lamina borders frequently found in this population. This
individual has only five lateral laminae on each side.

were: 11-11, 11-12, 13-11, 12-13, 13-13, 14-12, 15-15. Out of 259 spe-
cimens 120 had no intergular lamina, 66 had one, and 73 had two.
Asymmetry in the number of lateral laminae is nearly as frequent
in L. olivacea as symmetry; of 208 Surinam hatchlings 86 were asym-
metrical. Of these, 51 had more laminae on the left than oi the
right, and 35 had the reverse. This agrees with Carr (1952) "In
East Pacific specimens (at least) the higher number is usually found
on the left side."
Adults of L. olivacea with the 5-5 lateral count are still distin-
guishable from L. kempi by the high, flat-topped carapace (Figure
21) and also by the olive-green rather than gray colouration. Also
kempi averages a little wider than olivacea (Figure 15), the mar-
ginal laminae in the region of greatest width being wider than long,
instead of the reverse. One commonly finds specimens of kempi,
particularly young ones, in which the carapace as a whole is wider


Figure 20. Shell of adult Lepidochelys olivacea from Shell Beach, Guyana, (right)
with five lateral laminae on each side; shell of hatchling (left) for
comparison. Note overall retention of carapace outline, but marked
narrowing of central laminae with growth.


Lateral laminae


Brood 1


Brood 2 Brood 3


- 1

Vol. 13


Figure 21. Anterior profile of Lepidochelys olivacea from Eilanti, showing the
elevated, flat-topped carapace.

than long, a condition I have never found in olivacea. Skulls of the
two species are very similar, but the alveolar surface of kempi has
a definite bony ridge while that of olivacea is practically flat. Other
skull differences include the relatively larger orbit of olivacea, as
well as the greater minimum width across the pterygoids. For these
reasons I believe maintaining kempi and olivacea as distinct species
is well justified, although olivacea overlaps with kempi in three
characteristics formerly considered peculiar to kempi viz.:
1) L. olivacea shows some aggregated nesting emergences.
2) It sometimes nests by daylight.
3) It sometimes has only five lateral laminae on each side.
Many of the female ridleys at Eilanti had the thin horny laminae
in the rear third of the carapace missing, exposing a layer of thin,
tough, black tissue with the consistency of hand rubber. Possibly
the laminae in this region were eroded by friction with the male's
plastron during copulation.
Hatching percentages for ridley nests on Bigi Santi are strikingly
high. All the eggs in a clutch of 88 hatched normal offspring. Of
another clutch of 126 eggs, 3 opened before hatching all contained
living embryos. Of the remainder 118 hatched, 2 were infertile, and
3 were slow developers. The following incubation periods were
recorded by Mr. Plak (timed from laying of eggs to emergence of
young at surface, in days): 49, 50, 51, 51, 51, 51, 53, 53, 54, 55, 55, 56,
57, 58, 58, 59, 59, 59, 61, 62, 62, 62. All clutches were allowed to hatch
where they were laid. The hatchling ridleys were uniform gray-black
in color with a small white mark at each side at the supralabial scale,
another on the hind part of the umbilical protruberancc, and more



where the ridges of the plastron cross the abdominal and femoral
laminae. The extreme border of the carapace and a very thin line
along the trailing edge of both fore and hind flippers were also
white. This coloration is similar to that of hatchling kempi described
by Carr and Caldwell (1958), except that olivacea lacks the thin
white mark in the anal region.
Apparently the ridley is rare here, and I have no positive evi-
dence of nesting, although local Indians told me that a few nest on
the beaches on the French Guiana side of the mouth of the
Marowijne River. There is little doubt that these merely represent
a spillover from the large ridley rookery at Eilanti. Shrimp trawlers
quite frequently catch ridlcys in deep water off the coast of French
Guiana, and this area is probably an important feeding ground for
the ridleys that nest at Eilanti. I saw shells of two adult ridleys
which had been caught at sea in a fisherman's camp between the
mouth of the Organabo River and Sil6bache Beach.
At present I can offer no opinion on the probable length of time
the ridley has been established in the Guianas. The fact that its
presence there was overlooked until so recently is irrelevant, as the
species has been familiar to locals, if not to scientists, for many
years (Kappler, 1881). Nevertheless the restriction of the species to
a relatively small part of the coast of South America does suggest
that the population there was "seeded' by gravid individuals drifting
from West Africa, where they breed over a wide area. In future
studies the writer hopes to ascertain whether the Guiancse ridley
shows stronger morphological and behavioral affinity with the West
African or with the East Pacific population. No ridley of either
species has ever been found in the Caribbean. Pope (1939) records
a ridley from Jamaica, but Caldwell (1961), refutes its occurrence
there. Some sort of ridley, presunibly kenmpi, is reported to nest in
small numbers in Quintana Roo (Carr, 1957); and the fishermen of
Isla Fuerte, near the mouth of the River Sinu in Colombia, express
familiarity with a ridley-like turtle (Medem, 1962).

Dermochelys coriacea
In Guyana, the leatherback is called matamala, a curious use
of this name which possibly refers to any turtle with a strikingly

Vol. 13


ridged shell. It nests on Shell Beach, probably in rather small num-
bers. I have seen no living specimens there, but I found remains
of two leatherbacks slaughtered in August 1964 and four more in
August 1965. Meat-hungry Amerindians kill these turtles, usually con-
sidered inedible, with vigorous machete blows on the head and neck,
and carve them up for food. Three more or less intact carapaces I
found had lengths of 55, 61, and 65 inches. N. O. Poonai tells me
a "fair amount" of leatherback nesting also occurs at Punta Playa,
on the Guyana/Venezuela border.
The following data may help establish the nesting season of the
leatherback in Guyana: two leatherbacks were found freshly killed
on Shell Beach in mid-May by Dennis Joaquin, a settler on the
Waini River who gave much help with the project; two independent
witnesses agreed that a large scuffed-up area of sand was a leather-
back nest that had been made 'about a month ago', i.e. early July;
a leatherback nest almost ready to hatch, probably 6 or 7 weeks
old, was exposed by wave action on 6 August and the young des-
troyed by vultures. From these data we may infer that leatherback
nesting in Guyana occurs from at least early May to early July,
the same as the nesting season of the species in Trinidad (Carr
1956) and in Surinam. According to Jerome da Silva, a local turtle
hunter and egg collector, an occasional individual nests as early
as January, earlier than any other species.
The local Carib name is couana. The species nests in fair num-
bers on Bigi Santi; in early May 1966 about three nests were made
each night on the 3-mile stretch of beach cast of the research camp,
but after 24 May the leatherback season seemed to end abruptly.
We found one specimen nesting at Eilanti on 12 July. In the 1968
season it was not rare for 9 or 10 leatherbacks to nest in one night
at Bigi Santi.
An interesting belief in Surinam is that two kinds of leatherbacks
nest in the country, known respectively as sixikanti and aitkanti
(6-sides and 8-sides). Schulz (1964) gives nesting data for the two
forms separately. When I wrote him for details of the difference
between the two he replied "I have never had the opportunity to
ascertain the difference between 8- and 6-kanti, as I did not per-
sonally see the last one; I hope you will have more success in the
project." All the 25 leatherbacks that I examined in Surinam were
aitkanti, possibly because we arrived late in the season and the
6-kanti supposedly nests earlier than the 8-kanti. I asked Mr. G. Plak,


the chief game warden in Surinam, if he could elaborate on the
differences. According to Plak, they are as follows:
The terms aitkanti and sixikanti refer to the number of flat sides
visible when the animal is resting in the normal position on its
plastron. Thus the aitkanti has six sides on the carapace, bounded
by the seven ridges, and the outermost side of the plastron on each
side is also visible when the animal is on its belly, giving a total of
eight. The aitkanti is reportedly a little longer and substantially
heavier than the sixikanti, having a much more massive shoulder
region. In addition, the sixikanti lacks the vertebral ridge, while
this is very well defined in the aitkanti. Completed nests of the two
types may also be distinguished, as that of the sixikanti is relatively
smooth, and the imprints of the foreflippers in the sand do not show
turned-over tips, while the completed aitkanti nest includes piles
of sand thrown up by the foreflippers, and the imprints of the fore-
flippers show the last 4 inches or so of the flippers to be folded
back. The normal egg complement of the sixikanti is reportedly
50-65, while the aitkanti lays upwards of 70 normal eggs. Hatch-
lings of the two forms are said to be indistinguishable. Any dis-
cussion of the significance of this apparently dichotomous popula-
tion must await the description of the sixikanti by a competent
Size of mature females: Mature female leatherbacks from
Surinam had the dimensions shown in Table 7. These are very

Table 7. DIMENSIONS OF MATURE FEMALE Dermochelys coriacea FHoM BTCI
Caiapace length Carapace width Head width Plastron length

58%/ 31 9 43
59% 35%/2 10
60 -
60 -- -
61 92 -
62 33 10
62 36 10
63 9
631/ 1 -
64 33 8% 48
64 10
64 -
64 9%
65 10
661 41 101A
67 10%

Vol. 13


z 3-
cy 2_

58 59 60 61 62 63 64 65 66
Figure 22. Carapace lengths of adult female Dermochelys coriacea from Surinam.

similar to those found by Hughes et al (1967). Substantially larger
leatherbacks have been found in Florida; Caldwell (1958) mentions
two with carapace lengths of 74" and 79" respectively. The method
of measurement was not stated, but over-the-curve and straight-
line measurements for leatherbacks differ by only a couple of inches.
Most of the Surinam leatherbacks we found were too big to turn -
hence the dearth of measurements of plastral lengths but we
managed to turn and weigh the smallest one found. Its carapace
length was 58.5 inches, its weight 651 pounds. Even severely
molested leatherbacks made little show of pugnacity but the sheer
force of their movements on land and the vigor of their flailing
flippers when turned make one treat them with caution. None of
them emitted the loud sounds that have been reported for disturbed
leatherbacks; their stomach gurgling and their deep, throaty breath-
ing were the loudest sounds we heard them make.
Leatherbacks nesting on Bigi Santi start digging the egg cavity
a few minutes after selecting the nest site. They excavate no deep
body pit, which contrasts sharply with leatherbacks in Costa Rica,
where they dig a pit so deep that the top of the carapace is level
with the surface of the sand. Dr. Carr tells me that a Costa Rican,
returning home drunk along Matina Beach, fell into a leatherback
pit and had his wrist broken by a slap from the turtle within. No
such accident is possible in Surinam, where the turtle's plastron is
hardly lowered below the surface of the sand, and the nests are
correspondingly so much shallower than those in Costa Rica that
the eggs are much easier to find with a probe. Whether or not a
body pit is dug probably depends on the depth of the dry surface
sand; the turtle must reach moist sand before it can scoop out the
flask-shaped nest cavity.
I made the following field notes on Bigi Santi 11 May 1966:
The turtle was found facing towards the sea. After a number of


Figure 23. Left, above and below: leatherback turtles from Surinam. The range
of the spotted pattern of these two turtles encompasses that of a
Florida leatherback (above right), and a Costa Rica leatherback
(below, right), as well as that of the Indo-Pacific leatherbacks shown
in Figure 24.


Figure 24. (above): a Tongaland Leatherback; (below): a Trengganu, Malaya,

movements involving the front flippers, not observed closely because
of the dark, she reversed her position, facing inland. She then sprayed
a considerable amount of sand on her back and began to dig the
egg cavity. Using her hind flippers alternately, she scraped two or
three times with the leading edge of each at the opposite side of
the hole before lifting out a quantity of sand, which she pushed
away with a sharp forward jerk just before reinserting the flipper in
the cavity, much as do other species of sea turtle. When she was
scraping at the cavity with one flipper, she pressed her tail against
the opposite side of the mouth of the cavity, smoothing sand away
with an active muscular movement of the tail and cruro-caudal fold.


Figure 25. Position of flippers of leatherback during oviposition. The left flipper
is inside the nest cavity.

She shifted the rear part of her carapace through about 15 inches
between each excavation, the force for this movement being gen-
erated by the fixed hind flipper (i.e. the one which had just been
removed from the nest cavity). Her foreflippers remained anchored
throughout the operation. The maximum depth of the cavity was
reached fairly quickly, but enlarging the base to give the cavity
its flask shape took a long time and was carried out very thoroughly.
Then with one hind flipper still in the nest cavity (Figure 25)
she started to lay the eggs. The flippers overlapped each other slightly,
so that a little sand had to be cleared away to see the eggs. The
first ones were all of normal size, but she produced a quantity of
undersized eggs towards the end of the clutch. During each depo-
sition she tilted her carapace very slightly just before actually drop-
ping the eggs. From time to time she raised her head sharply. Some
contraction of the muscular surface of her hind flippers was noticed
during deposition, but no actual movement of the limbs.
When she presumably had laid all her eggs, she swept sand
into the cavity with her hind flippers. After each sweep the flipper
flattened the sand down with up to about eight slaps. When the
cavity was full and a pile of sand had formed over it, she swept the
pile left and right with alternating movements of her hind limbs.
She continued this movement for some time until the nest spot was

Vol. 13


Figure 26. Carib Indians at Eilanti waiting to collect leatherback eggs.

completely hidden, then the hind limbs stopped and she swept
sand back with a powerful simultaneous movement of her forelimbs.
The alternation of these two movements carried her about 5 yards
from the nest site. After about 3 yards she laid a few more under-
sized eggs on the ground. Gradually she changed the sand-sweeping

Figure 27. Close-up showing unusually copious, viscous 'tears' of nesting leather-


movement to a humping-forward movement that carried her back
to the sea.
Another turtle watched 6 June started digging the egg cavity
with the trailing edge of her hind flippers. This gradually became
the normal movement using the leading edge, but her left flipper
seemed injured and, although she went through the normal digging
motion with it, she moved it awkwardly and could not remove sand
with it. Another turtle nesting in deep dry sand spent more than
70 minutes digging the nest cavity. Since she was unable to reach
moist sand layers she was unable to give the cavity a flask shape.
Still another turtle not only nested well below the high tide mark
but also was unable to dig the nest cavity because of some hind
flipper malfunction. I had both to dig the egg cavity for her by
hand and then move the eggs higher up the beach out of reach
of the tide.
Leatherbacks occasionally leave the sea by day on Bigi Santi.
I saw emergences at 4:15 PM and 6:15 PM (still light) on 7 May,
but although we watched from a safe distance the turtle returned
to the sea without nesting in both cases. I was told that earlier in
the season leatherbacks had been seen emerging at 8:00 AM and
4:15 PM.
Interesting period, clutch size, abnormal eggs, and incubation period:
Leatherback nests on Bigi Santi invariably include a proportion of
undersized eggs, as they do elsewhere. We found no true dumbbell-
shaped eggs, but some of the undersized ones had knob-like swell-
ings. I recorded the following egg complements: 58 normal + 40
undersized, 69 + 11, 70 + 1, 83 + 23, 100 + 35, 101 + 39, 120 +
12, 126 + 40. Some other nests, in which only normal eggs were
counted, contained the following numbers of eggs: 57, 65, 66, 70,
72, 72, 72, 75, 76, 79, 81, 83, 84, 86, 87, 90, 92, 98, 100, 102, 106,
113 (M for Natal leatherbacks: 106 normal (SD 22), 30 undersized
(SD 27), Hughes et al, 1967; 6 nests from Matina and Tortuguero
Beaches, Costa Rica, contained respectively 66 normal I 38 under-
sized; 45 + 7, 73 34, 80 1 41; 74 4 ?, 66 + ?, Carr and Ogrcn
One turtle laid 10 undersized eggs, then was apparently disturbed
by the flashlight and she returned to the sea without covering up.
In several of the clutches examined a small minority of the eggs had
green flecks. Deraniyagala (1939) records the same phenomenon
in Ceylon leatherback eggs. Intervals recorded (in days) between
nesting emergences of tagged individuals are 32, 29, 28, 21, 11, 11,

Vol. 13


9, suggesting an interesting period of about 10 days. Hughes et al
(1967) report a similar period for leatherbacks in Natal. One in-
dividual, disturbed before nesting, returned about 11/' hours later
a mile up the beach.
I obtained no data myself on incubation, but Mr. Plak recorded
the following periods (in days) in 1964 for eggs allowed to hatch
where they were laid: 60, 60, 60, 61, 63, 65, 68. The only informa-
tion I have on fertility percentage is that, of a clutch containing 70
normal eggs and 1 undersized, all 70 normal eggs hatched and pro-
duced viable offspring. A random 25 of the hatchlings ranged in
length from 5.6 to 6.0 cm, and in width from 3.9 to 4.4 cm; 12 from
another nest ranged from 5.91 to 6.39 cm, and 27 from a third nest
from 5.46 to 6.06 cm. In appearance they were indistinguishable
from photographs of West African hatchlings in Villiers (1957).
When released on the beach they turned in the orientation circles
Carr and Ogren (1959) describe for Costa Rican leatherback
hatchlings; some of the circles were very small and complete, but
others were large and rambling or incomplete. Tracks of adults too
frequently showed tight circles.
Injuries Several of the adult leatherbacks had notches in the
hind flippers, possibly from shark bites. All the adult turtles of this
species seen in Surinam had a curious pink area on the crown of the
head. At first we assumed that this was the site of an old injury,
in which the skin had healed but to which pigment had not returned,
but its constancy suggests it is more likely caused by friction with
the chin or mouth of the male during copulation.
Kappler (1881) mentions that the leatherback, though seldom
found in Surinam, is plentiful in those parts of French Guiana where
rocks are plentiful in the sea. Geyskes (1945) makes similar re-
marks. According to Indian reports, nesting occurs from early May
to July and August, both near Cayenne and near the mouth of the
Organabo River. Extensive nesting in the latter area was proved
by my visit to Sil6bache Beach 6 June 1967; although I was only
able to explore the beach during a low tide period, when mud banks
prevent the turtles from emerging, this beach is clearly one of the
principal leatherback nesting grounds in the hemisphere and indeed
the world. For 3 miles along the beach we were rarely out of sight of
a fresh leatherback track and some sections were so cut up with tracks
and nests that walking along the beach was difficult. A local fisherman
told me that during offshore shark fishing, he usually caught during



the 2- to 3-month season about one leatherback per day, which he
killed and cut up for shark bait and for any shelled eggs it might
contain. It seems certain that at least several dozen leatherbacks
nest each night at Silebache during the peak of the season, compared
with about 80 per night on the 71/2-mile beach in Trengganu, Malaya,
which is considered the largest known leatherback colony. Silebache
Beach is known to the Marowijne Indians, who occasionally make
the difficult journey by sea and fill their boats with eggs. One
Indian to whom I spoke reported collecting 2000 eggs on a recent
trip, finding about 100 normal eggs in a nest, with the usual under-
sized ones always present as well.
We found small pieces of leatherback shell on the beaches of
Montabo, within the Cayenne city limits, and according to reports
nesting also occurs at Montjoly Beach, Bourda Beach, and Kourou
It is interesting that the coastal Indians in French Guiana also
recognize the two types of leatherback described to me in Surinam;
the local Carib names for the two types are tukutubuking for the
8-kanti and tibisibisiching for the 6-kanti. The latter was reported
to nest earlier in the year than the former, an observation corrobor-
ated by Surinam informants.

Some authors still follow Garman (1884) in recognizing the
Atlantic and Indo-Pacific leatherbacks as distinct subspecies coriaceaa
and schlegeli). Garman published no description of the differences
between these forms, but it has been suggested that the difference
lies in the size and number of the light spots on the carapace and
the extremities. Figure 23 shows two leatherbacks from Surinam,
not particularly chosen to show the extremes in coloration. Leather-
backs from Tongaland (Figure 24), Florida (Figure 23), Costa lic-a
(Figure 23), and Trengganu (Figure 24) can be seen to lie well with-
in the range of variation of spotting of those from Surinam. Some
Atlantic leatherbacks (photos in Carr, 1952 and Villiers, 1957) are
almost without spots on the shell. Carr (1952) remarks that the
spots are more pronounced in small adults than in large ones, and
I believe Surinam leatherbacks bears this out, though I did not
think of checking it at the time. Possibly the spots become smaller
and less distinct as the turtle grows older and larger.
It is often stated that the leatherback is the rarest of the sea
turtles, and that it may be on its way to extinction. Fitter (1961)

Vol. 13


estimated the world leatherback population to be possibly as low
as 1000 mature females, of which 850 nested at Trengganu, Malaya.
I cannot accept these estimates. While leatherback populations are
probably smaller than green turtle populations, this is almost cer-
tainly because the equilibrium numbers in undisturbed habitat are
smaller. In fact it may be the least seriously threatened of the sea
turtles. It is of little commercial value, its meat being oily and to
most people inedible, (though a sample I ate in French Guiana was
very tasty), and its shell is not utilized. These factors combine to
make human predation on the adults small. The eggs, though edible,
are buried deep in the sand, and thereby gain a certain immunity
to discovery by the usual mammalian and reptilian predators, and to
some extent humans (though eggers are a serious problem in the
Malayan and Costa Rican rookeries).
Leatherbacks are hardly ever found at sea in the tropics, and
specimens of intermediate size are almost unknown. A possible rea-
son for this is that the leatherback may be able to remain at great
depths at all times except when breeding, and to obtain enough
oxygen for its needs by pharyngeal respiration without having to
surface to breathe. The curious papillose structure in the leather-
back's throat may serve as an oxygen exchanger, though it has also
been suggested that this structure serves to prevent the jellyfish
on which this turtle feeds from sliding back up the throat (Bleakney
1965). Another possibly significant fact is that healthy, active leather-
backs are encountered in cold northern waters with a frequency
that seems to preclude accidental drifting; 30 leatherbacks are re-
corded from the British Isles, while numerous records also exist for
Japan, Siberia, Norway, Nova Scotia, Maine, and Newfoundland
(Bleakney 1965). Leatherbacks from the latter areas are active and
have stomachs full of jellyfish (Cyanea capillata artica), suggesting
that the habitat is not so hostile as to inhibit feeding. MacAskie and
Forrester (1962) report vigorous activity in a leatherback in water
as cold as 53F (11.7C) in the Queen Charlotte Islands, a tempera-
ture at which most reptiles are extremely sluggish. Perhaps the
leatherback has achieved a degree of endothermy; its large size,
barrel-like shape and 2-inch layer of oily connective tissue under
the shell would certainly help retain metabolic heat. In an attempt
to shed some light on this problem, Nicholas Mrosovsky and I tried
to get deep-body temperatures of adult female leatherbacks and two
other species of sea turtle by taking the temperature of the interior
of just-laid eggs. Four leatherbacks gave temperatures of: 30.0, 30.0,


30.5, 31.250C. Two green turtles gave temperatures of 29.0 and
30.250, while three ridleys gave 28.0, 29.0 and 29.500. Sea tempera-
ture was approximately 280C.
A drawback to the above argument is that no other animal is
known that combines the features of pharyngeal respiration with
endothenny. A possible explanation, without a shred of direct evi-
dence but which at least fits the facts, is that the leatherback is
ectothermous in tropical waters and lives at great depths, respiring
by pharyngeal oxygen exchange, while in cold northern waters it
becomes endothermous and breathes atmospheric oxygen; the latter
habit would account for the relatively frequent sighting and capture
of leatherbacks in the north. No small leatherbacks have been found
in northern waters; perhaps the young turtles remain in the tropics
until they reach adult size, possibly feeding on more substantial food
than the jellyfish that apparently form the principal subsistence of
the adult leatherbacks caught around Nova Scotia.
An alternative hypothesis is that the leatherback has developed
a fishlike metabolism, in which cold ambient temperature is not in-
compatible with moderately high degrees of activity. Much progress
will be made towards a solution to this problem when deep-body and
cloacal temperature measurements are available for leatherbacks in
northern waters.

Eretmochelys imbricata
Called "carey" in Guyana, I found hawksbill turtles nesting in
fair numbers on Shell Beach in August. Although the relative abun-
dance of their shells and skulls on the beach suggested that nesting
had been in progress for some months, I saw 14 nesting emergencies
and found 12 other fresh nests during the 3-week observation period.
The mean carapace length of 33.1 inches is close to that for Tortu-
guero hawksbills (M = 32.72, n 62; Carr et al., 1966).
The heaviest specimen I found (165 pounds after oviposition)
was unusually heavy for a hawksbill, though a long way short of the
record held by a 280-pound turtle from the Cayman Islands (Lewis,
1940). This record hawksbill, unless unusually fat, must have been
about 42 inches long, as big as a big green turtle. The shells of most
hawksbills found had large barnacles, as they do at Tortuguero (Carr
et al., 1966). On the other hand the green turtles and ridleys on
Shell Beach were practically free of them.
The hawksbills usually completed nesting within an hour, but

Vol. 13


31,5 32 32-5 33 33-5 34 345 35
Figure 28. Overall carapace lengths of adult female Eretmochelys imbricata from
Shell Beach, Guyana.


Eretmochelys imbricata, SHELL

Empty carapaces: Length



26 %

givingg specimens: Plastral length Weight (Lbs.)

32 22%1 231% 98
32 25 26 -
322 22 24 139
321/2 22 / 25% 134
32% 241/2 25 133
321/ 241/2 251 130
33 22% 25 118
33 23 26 -
33 24% 241 134
33 25/ 25/ 165
331/2 24 25 145
35 24 26 139

one turtle produced a clutch of broken and deformed eggs according
to the following prolonged schedule:



2:00 AM Turtle found digging nest cavity.
2:23 Cavity completed
2:29 First egg laid, after several minutes straining, with occa-
sional raising of the margins of the hind flippers. The
next egg was squashed and broken in the cloaca. She
went on to lay a totally deformed clutch; many eggs
were broken before laying, some were small and ovoid,
and others were in long strings. She also produced a few
apparently normal eggs. Each deposition was accompanied
by a curling-up of the margin of the hind flippers, an in-
variable stereotype of the nesting of this species. Some-
times two eggs delivered side by side caused abnormal
distention of the cloaca.
3:10 Last egg laid. The turtle did not seem to realize when the
eggs stopped coming, and she went on straining for several
minutes. This waiting period was not observed for other
hawksbills, but it is a frequent practice for green turtles.
3:27 Turtle, still straining, was deliberately disturbed by blows
on head and shell, and she finally started covering.
3:35 Nest cavity filled. Turtle left without filling in body pit.
Two turtles were accidentally disturbed before they had started
nesting; they were tagged and allowed to return to the sea. One re-
turned later the same night, the other the following night.
Clutch size and egg dimensions: Clutches of the following sizes were
found: 139, 145, 152, 159, 167, 169, 176. (M = 158; ef M 161.1
at Tortuguero, Carr et al., 1966).
Egg diameters ranged from 36 to 40 mm. I found no abnormal
eggs other than those mentioned above. Hawksbill turtles on Shell
Beach were no more pugnacious than the green turtles, and never
attempted to bite. Turned hawksbills slapped for a time, but soon
quieted down, and they could be left until the following morning
without injuring the edges of their flippers.

The local name here is carett. It is rare and the only one I saw
was an empty shell at an Indian encampment near Eilanti. Four
nests were recorded by the Surinam Forest Service in 1964, on 16
June and 4, 5, and 25 July. Ten hatchlings from one of these nests
preserved by Forest Service personnel ranged in carapace length from
4.13 to 4.37 cm, in width from 2.79 to 3.17 cm, and in plastral length

Vol. 13


from 3.33 to 3.60 cm. No laminar variation was evident within this
series; all ten had 11 marginals and 4 laterals on each side, 5 verte-
brals, 2 supracaudals, 1 nuchal, I intergular and 1 internal. Derani-
yagala (1939) also found no laminar variation in 18 sibling hatchlings,
but in another clutch laid by a clearly senile female with completely
closed carapacial fontanelles half of the 22 young examined showed
deviations from the typical laminar condition.
Kappler (1881) wrote the following notes on the hawksbill in
Surinam (in translation from Schulz 1964): "Very seldom, and never
earlier than June, the caret turtle (Chelonia imbricata) comes on
land. She weighs about a hundred pounds, and the upper jaw is
beaked just like a parrot. The meat is not eaten, and the people even
say that it is poisonous. This is the source of true tortoiseshell, and
one turtle sometimes yields l1/2 to 21/2 kg. of the material. It is
very beautiful, but people do not value it as highly as that of the
East Indies. The caret is called waroa by the Indians. Another one,
Chelonia onychochelys kraussi (Gray) is similar in form and color
but the shell is thinner and has no value at all."

The hawksbill is reportedly seen often in the waters around Devil's
Island, and nesting probably occurs abundantly on several beaches
in the country. According to local reports hawksbills nest on all three
beaches of the Ile de Cayenne, and I found hawksbill tracks and
nests at Silebache Beach 6 June. I also saw quite a number of
mounted hawksbill heads and shells in hotels and restaurants in
St. Laurent and Cayenne.
An Indian I spoke with told me that two types of hawksbills occur
in French Guiana, one small enough for one man to lift off the ground,
the other a heavy load for two people. He stressed the point that the
two were distinct and that the small kind does not grow into the
big kind. Possibly the larger ones are loggerheads, and represent an
interesting outlying breeding enclave of this species. In the hope of
shedding some light on this problem I recently examined the type
material of Gray's Onychochelys kraussi, a sea turtle from French
Guiana, in the British Museum. The material, consisting of a large
stuffed adult with a 36-inch carapace and the skull of another indi-
vidual, is unquestionably referable to Eretmochelys imbricata. Gray
was probably familiar only with immature hawksbills, and did not
realize that adults could reach this size.


Caretta caretta
The true loggerhead, Caretta caretta, has never been found nest-
ing in the Guianas, but Carr (1956), reports it occurs in deep water
off Trinidad perhaps 150 miles from Guyana, and Brongersma (1968)
records three specimens, at least two of them about half grown, from
Surinam waters. The species occurs occasionally in Southern Brazil
(a large adult skull in the British Museum is from Itapema Beach,
Northern Santa Catarina State, Brazil), but the only South American
nesting grounds appear to be on the coast of Colombia.

At present no laws protect sea turtles in Guyana. The principal
nesting area, Shell Beach, was until recently partially protected by

Figure 29. In Guyana sea turtles are exploited for their meat as well as their
eggs; this large hawksbill turtle was taken while nesting on Shell

its remoteness. Today parties of hunters make their way to Shell
Beach during the nesting season, camp there for a few days, collect
as many eggs as they can find, and usually carry off, dead or alive,
one or more of the nesting turtles (Figure 29). These hunters, Portu-
guese, Negro, or Amerindian, come either from the North-West Dis-
trict or from the Pomeroon area, and travel in small sailboats, some
of which are power-assisted. In 1967 we found that an offshore oil


prospecting company had established a shore radio base on Shell
Beach, and the two full-time caretakers were killing almost all turtles
that nested for their meat, which they preserved by sun-drying. Fol-
lowing Venezuela's claim to the entire North-West District in the
summer of 1968, I read in the Guyana "Graphic" that the oil com-
pany was ceasing operations in the Shell Beach area.
Apparently a live adult hawksbill sells for only $5 ($3 US) in the
North-West District, but will fetch $15 in the Pomeroon, where an
adult green sells for $35-40. The higher price of the green turtle
merely reflects the greater amount of meat obtainable from it; no
preference for the flavor of the green turtle was expressed. The
leatherback is considered inedible by all except Amerindians, who
kill them and cut them up where they find them. Turtle eggs fetch
1 cent to 5 cents BWI each, according to temporary scarcity; about
3000 were removed during my stay. As a rudimentary conservation
measure I reburied 1518 eggs within 12 hours of their being laid,
in a series of carefully disguised artificial nests; these probably
hatched, though egg destruction by sand crabs as Caldwell (1959)
describes is possible. Some eggs are lost by being laid too close to
the sea where the beach is being eroded.
Estimating the number of nesting turtles killed on Shell Beach
each year is very difficult, but it is probably at least 100, and possibly
many more. Even in the large green turtle colonies of Ascension,
Aldabra, Tortugucro, and the Talang Islands, the total number of
breeding individuals is only of the order of a few thousands, and
small colonies such as that of Guyana probably number only a few
hundred mature individuals. Two independent informants, Harold
Hirth and Jack Frazier, inform me that the Aldabra nesting colony
has now been virtually exterminated by overhunting of the nesting
females, either on the beaches or in the lagoon. Offshore harpooners
and beach veladores have also made a serious dent in the Tortuguero
population, where the 1968 season was by far the poorest on record.
Ample evidence now demonstrates that slaughter of nesting
females is the surest way to decimate the population, and for this
reason governments in many countries have passed laws protecting
turtles on nesting beaches. It is highly desirable that such laws be
passed and enforced in Guyana, and recommendations to this effect
have been made several times in the last 4 years, though up to now
they have been ignored. If laws are not passed, increased turtle
exploitation will follow increased population pressures, and the inevi-



table result will be the extermination of the Guyana turtle nesting
The Surinam Government has been commendably alert to its
responsibilities to protect its relatively newly discovered sea turtle
populations. Killing sea turtles is strictly prohibited everywhere in
the country, and so far as I could judge this ban is rarely infringed.
It is also illegal to take eggs anywhere in the Wia-Wia Nature
Reserve, which includes Bigi Santi, an important nesting ground for
the green turtle and the leatherback. Egg taking is legal on beaches
near the Marowijne River, and the Indians in this region resent any
attempt to interfere with their rights to this resource. The Indians
can predict quite accurately when the massive aggregations of nest-
ing ridleys are due to arrive on the beach at Eilanti. They move
down to the beach and endure two or three sleepless nights in order
to collect as many eggs as possible, and very few escape them. The
exploitation is highly organized, and the village captain allots each
man a small section of the beach on which to collect eggs. Huge
piles of turtle eggs accumulate in the Indians' huts on these arribada
nights (Figure 13); they are taken to Paramaribo by boat and sold
wholesale for approximately 15 guilders ((en. $8.50 US) per thousand.
The retail price in Paramaribo is about one guilder for 30.
Apparently the best way to ensure the continued existence of these
spectacular aggregations of turtles would be to prevent exploitation
of eggs on Eilanti completely in certain years. This was done in
1967 and 1968 by purchasing the entire season's production of eggs
with funds from the World Wildlife Fund. In 1967 these were
transferred to an artificial hatchery, and a hatching percentage of
60-70 per cent was achieved; in 1968 they were allowed to hatch in
No laws protect sea turtles in French Guiana at present, and the
consequences of killing leatherbacks for shark bait at the present
rate will eventually be serious. Large numbers of eggs are collected
at Sil6bache Beach, but as the beach is quite long and remote it
suffers nothing like the 100 per cent loss normal at Eilanti. Fair
numbers of turtles, probably mainly ridleys, are caught at sea by
shrimp trawlers. Sometimes these are killed and eaten, sometimes
they are released alive.
Recommendations have been made to l'Inscription Maritime at
Cayenne that laws protecting the turtles must be passed and enforced,
and promises have been received that these will be acted upon. But
the remoteness of the main nesting beach from any center of civili-

Vol. 13


nation and the energy with which the Indians and creoles hunt
turtles and their eggs will continue to make turtle conservation
in French Guiana extremely difficult.

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Loiden. 51: (2) + 46, 9 figs., 1 pl.
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