Photo by Russ Gurley
and David S, Lee
Asian Turtle Consortium
The Spotted Pond Turtle, Geoclemys hamiltoni (Gray) is a large (up to 36 cm) rare, aquatic turtle restricted to the Brahmaputra, Ganges (Ganga) and Indus (Sind) drainage systems of northern India, adjacent Nepal and Bangladesh, and extreme western Pakistan. The Nepal record is from the India-Nepal border (Moll and Vijaya 1986) and the turtle is probably only peripheral in the latter country. The species is also known as the Black Pond Turtle, the genus is monotypic, no subspecies are recognized and geographic variation has not been reported. Little primary literature exists on the natural history of the species and most accounts are primarily taxonomic descriptions. There are no major accounts written by people personally familiar with these turtles and only a few published notes by people who have worked with t! he species in the wild exist (Smith 1931 and Das 1985, et sequel). Most general accounts do not provide references and it is difficult to identify the original sources of the scant available information repeated by various authors.
This Batagur lives
in rather clear shallow water with abundant aquatic vegetation. Pritchard
(1979) reports that these turtles live in oxbow lakes and sloughs. Their
highly domed shell suggest that this is not a turtle of swift currents so
they probably do not inhabit the main channels of large rivers on a regular
basis. While they do occur in rivers this seems to occur during seasons when
river flood plain ponds are dry and the rivers are themselves are low. In
the more arid northern portion of their range ponds and rivers may
completely dry up by the early summer. At such times the turtles migrate to
wells dug in river-beds (Das 1985). Subsequent to the original naming of the
species (Gray 1831) detailed descriptions of the turtle have been provided
by Tikader and Sharma (1985), Das (1991), Pritchard (1979), Ernst and
Barbour (1989), and others.
Here we report on the long-term captive breeding of this species as part of an on-going conservation effort for rare and endangered Asian turtles. The adult turtles are being maintained in outside enclosures in central Florida (ca. Latitude 27.5 N).
stock and current size of the breeding group : Five wild caught
juveniles were acquired in 1971. An additional two sub adult founders were
acquired in 1990. The current breeding-group consist of the original 7
founders, 26 turtles from a 1997 hatch which are now breeding adults and 4
turtles of a new blood line from a breeding loan. Offspring from the
breeding group which are now sub adults and juveniles are also part of this
collection (1998 24 individuals; 1999 31 individuals; 2000 51
individuals; 2001 67 individuals; 2002 53 individuals;! and 2004 ca 100
individuals. The eggs were not found in time to incubate them in 2003.) An
additional 25 individuals from this breeding group are held by various
members Asian Turtle Consortium (see below). This represents the largest and
most significant successful captive breeding group of these turtles known.
It also is the longest term, most consistent, and only multi-generation
program in existence for this globally endangered species.
Food : In the wild Spotted Pond Turtles are reported to feed primarily on snails. Wild caught turtles from Pakistan voided snail opercula and undigested algae. The alga was believed to have been ingested incidentally (Milton 1966). Dias (1991) reports Geoclemys feeding on the snails, Lemnaea and Gyruls, and dragonfly larvae. The large heads and! cusps and ridges in the turtle's mouths are probably adaptations for crushing snails. Their occurrence in quiet waters with abundant aquatic vegetation is probably related to the fact that this vegetation supports extensive snail populations. In captivity this species is reported to eat meat, fish, shrimp, and insects and it is not known to eat plant material. Captive animals in Florida are fed primarily on defrosted frozen whole fish and commercial fish chow. They feed while swimming at the surface on the fish that are suspended on clothespins and eat pellets floating on the surface. However, they also consume aquatic animals living in their ponds and tanks. Water hyacinths placed in the ponds and pools housing adult and sub adult Spotted Pond Turtles are gradually striped of their roots. It is assumed that this is a result of turtles gleaning aquatic invertebrates from submerged root systems of these plants and that the roots are not a food source per se . Captives in North Carolina showed a similar behavior and gradually over several months striped roots of water lettuce.
Captive Breeding Facilities: Initially the adult turtles were housed outside in a circular pool with a 6-meter diameter containing about 1 meter of water. Floating aquatic vegetation and a few sunning logs were provided. A ramp leading to a covered, sand filed nesting box was attached to one side of the pool. Turtles were fed daily. In the summer of 2002 the adult turtles and two large f1s from the 1997 hatch were moved to a large fenced out door pond. An electric fence runs along the sides of the enclosure. The open pond encompasses about two-thirds of the 50 x 100 meter enclosure and averages about 1.5 meter in depth. Aquatic vegetation covers a small percentage of the total surface area, and Tilapia were introduced to the pond. The land portion of the enclosure is maintained in mowed grass with a few open sandy area! s for nesting. The 28 f1s from the 1979 hatch were moved to the out door pond housing the seven founders in September of 2004. Hatchlings and juveniles are housed in large plastic tubs with each year class housed separately with the older groups living outdoors. All age classes are fed daily. Eggs are incubated in damp vermiculite a walk in temperature controlled incubation room. Each clutch is kept in a separate covered container. The turtles are not housed with other species of chelonians.
Activity Periods: Das (1991) states that Geclemys are crepuscular, and we see some evidence of this in our captive population. However, a few turtle heads can be seen throughout the day, they respond to food whenever they are fed, and turtles bask in the heat of the day, during the cool months of fall and winter, whenever sunning sites are exposed to direct sun. Turtles maintained out doors are shy and hide from view when approached. January temperatures in Central Florida average about 63 F, and the number of frost days average less than 5 per year.
Breeding: As recently as the mid 1980s nothing was known regarding the breeding habits of Geoclemys (Tikader and Sharma 1985). Subsequently Indraneil Das has assembled antidotal information from local people familiar with the turtles, Rotmans and Rotmans-Zwaal (1984) report on information from a captive group in Europe, and Basu and Singh (1998) describe various aspects of the breeding biology based on a small captive breeding group in India.
Breeding season: Summaries of literature state that nesting extends from May to October but the original sources for this statement are unclear. Das (1991, 1995) reports he was told that nesting corresponding with the monsoon season, with laying both prior to and just after the monsoons in February and again in October. Basu and Singh (1998) report courtship in February and March and discuss five nests laid in April and May. They mention that there is variation in the breeding season in different portions of the turtle's range. The breeding group discussed here lays from 13 April through 7 June with the majority of the eggs produced in May.
Mating: Basu and Singh (1998) describe courtship in February and March with males mounting and biting the back of the head females. The breeding group discussed here mate in Florida in January and February as opportunity allows.
Nest : With rare exception the Florida breeding group chooses the west bank of the pond to nest. The soil in the nest hole is first wet with body fluids from the laying female. The nest holes are as deep as the turtle can reach with the back legs, so they vary in depth with the size of the turtle. All observed nesting was from 4 pm to midnight .
Eggs/clutch size : Egg size is reported in literature at 41-45 x 25-37 mm (various sources). Information on the Florida group is as follows: Eleven eggs from a single clutch laid on 7 June 2004 measured 36-43 (38.5) x 21.0-23.0 (21.97) mm and weighed 9-15 (11.78) grams. The weight of the total clutch was 129.6 grams. Eggs from seven other 2004 clutches which had not hatched by 24 June when they were examined were all of similar sizes and weights. Eggs with weights that dropped below 10 grams failed to hatch. Adults produce two (Das 1991, 1995) to three (Rotmans and Rotmans-Zwaal 1984) clutches per year. Multiple clutches in our captive group are suspected but not confirmed. Clutch size is reported by several authors to be from 26-36 eggs. Basu and Singh (1998) describe clutches of 13 to 24 eggs. From our fi! rst successful reproduction in 1997 clutch size has increased each year as the turtles increased in size. Turtles laying clutches of 10-12 eggs in 1997 are now producing up to 23 eggs per clutch.
Incubation: Rotmans and Rotmans-Zwaal (1984) report an incubation period of 74 days, while Basu and Singh (1998) state the incubation time is 32-48 days. At 82 F eggs from the captive group reported here hatch in 60-64 days. Hatching success for fertile clutches varied from 50-95%, and was typically above 80%.
Hatchlings: Size of hatchlings is reported to be 35-37 mm (Rotmans and Rotmans-Zwaal 1984, Ernst and Barbour 1989, Das 1991). Information on the Florida group as follows: Nineteen young from a single clutch were weighed and measured by us on the day of hatching (24 June 2004). Their lengths were consistent in size with what has been reported in the literature. Total carapace length ranged from to 34.6 to 38.5 (37.0) mm. Width ranged from 26.5 to 29.7 (28.7) mm and height was from 19.0 to 21.2 (20.2) mm. Weights ranged from 10 to 12.6 (11.89) grams. In overall appearance the young resembled adults in coloration, although they were move vividly marked. The interpreted keels were pronounced and the posterior marginals were more serrated than those of the adults.
Growth and Sexual Maturity: Considerable variation occurred in the growth rates of all classes. Turtles hatched in 1997 reached breeding condition in 2004, thus in this year the founder stock, f1s and f2s are all represented in this captive breeding group. It is possible that a few of the 1997 f1s nested in 2003 and eggs were overlooked because of the shifting of housing. At any rate captive raised turtles reach sexual maturity and produce viable eggs within seven years. Size at first breeding is 216 to 250 mm and 1135 to 1515 (1385.4) grams. Standard carapace length increase averages about 28 mm a year and weight increase is about 198 grams/year during the first seven years needed to reach sexual maturity.
Conservation Status: This is a Red List species of the IUCN (1996) and it is considered low risk-near threatened. Listed as Endangered in the Bangladesh 1999 Red Data Book. The turtle is nominally protected by legislation in all range countries. It is protected by Schedule I of the Indian Wildlife Protection Act of 1972 and by Schedule III of the Bangladesh Wildlife Protection Act of 1974. Populations seem to have benefited by the creation of several sanctuaries created in northern India, but over all the species is declining in both numbers and in over all distribution. Geoclemys is protected under the USFWS endangered species act and has been protected from exp! ort since July 1975 by CITES as an Appendix I species. The pet trade is not a conservation issue in the United States market but it does appear in the pet trade in countries where CITES is not carefully enforced. They are eaten by Hindus and exported to the food markets in China from Bangladesh. In India some international trade exist but most are eaten locally. The species was fairly abundant through the early 20th century but it has now been depleted drastically throughout its range. Tikader and Sharma (1985) list the following conservation concerns: over exploitation of eggs and adults for food; habitat destruction; loss of nesting areas by commercial removal of sand; clearing of riparian and aquatic vegetation resulting in loss of cover for the turtles, food for aquatic snails, and soil erosion; and construction of hydro-electric dams and other barrages restricts the movement of adults to nesting sites. Many of the conservation issues are the result of extensive river f! lood plain agriculture in the region.
This breeding program reported here is but one of a number for rare and endangered Asian turtles under captive management by the Asian Turtle Constrain. This Consortium consists of about 100 active members all of which are in the private sector. These captive breeding groups serve as assurance colonies in case at some future date repatriation of various species is needed within their natural range. For many of these turtles little is known regarding their biology. So, in addition, various aspects of the natural history and captive husbandry of individual species are being learned and reported by Consortium members. To learn more about this Consortium visit www.asianturtle.org .
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Das, I. 1985. Indian turtles a field guide. World Wildlife Fund, Calcutta.119 pages
Das, I. 1991. Colour guide to the turtles and tortoises of the Indian Subcontinent. R & A Publishing Limited, Avon England.133 pages.
Das, I. 1995. Turtles and tortoises of India. Oxford University Press, Bombay. 179 pages.
Ernst, C. H. and R. W. Barbour. 1998. Turtles of the World. Smithsonian Institution Press. Washington, DC. 313 pages.
Gray, J. E. 1831. Synopsis Reptilium or short descriptions of the species of reptiles. Part 1. Cataphracta, tortoises, crocodiles, and enaliosaurians. London 85 pages.
Milton, S. A. 1966. A contribution to the herpetology of ! West Pakistan. Bull. American Mus. Nat. Hist. 134:27-184.
Moll, E. O. and J. Vijaya. 1986. Distributional records for some Indian turtles. Jour. Bombay Nat. Hist. Soc. 83(1):57-62.
Pritchard, P. 1979. Encyclopedia of Turtles. T. H. F. Publications, Neptune, New Jersey. 895 pages.
Rotmans, H. J. and A. C. Rotmans-Zwaal. 1994. Eengeslaagde kweek van de driekielstraalschildpad ( Geodemys hamiltoni ). Lacerta 53(1):11-17.
Smith, M. A. 1931. The Fauna of British India, including Ceylon and Burma. Reptilia and Amphibia. Vol. I, Loricata, Testudines. Taylor and Francis, London. 185 pages.
Tikader, B. K. and R. C. Sharma. 1985. Handbook Indian Testudines. Zoology Society of India, Calcutta. 156 pages.
(Hill) P. O. Box 3838, Winter Haven, Florida email@example.com ;
(Lee) P. O. Box 7082, White Lake, North Carolina 28337 firstname.lastname@example.org