Five Chinese big-headed turtles (Platysternon megacephalum) have hatched at the Wildlife Conservation Society's Prospect Park Zoo. Hatched in November, this is the first time the species has successfully reproduced at a zoo accredited by the Association of Zoos and Aquariums.
The Chinese big-headed turtle can grow to be about seven inches in length. It has a skull of solid bone that is so large in proportion to its body that it cannot be withdrawn into its shell for protection.
The Prospect Park Zoo is breeding this species as part of WCS's global effort to save critically endangered turtles from extinction. The strategy draws on all of the resources and expertise across the institution – including its zoos and aquarium, Wildlife and Zoological Health Programs, and Global Conservation Programs – to take direct responsibility for the continued survival of some of the world's most endangered tortoises and freshwater turtles.
"The success we are seeing at this point in our turtle propagation work is encouraging," said Jim Breheny, WCS Executive Vice President of Zoos and Aquarium and Bronx Zoo Director. "Our work on breeding endangered turtles utilizes the expertise found throughout the entire WCS organization as well as various partner organizations with whom we work."
WCS now has 15 Chinese big-headed turtles at the Bronx and Prospect Park Zoos –the largest collection of the species in any AZA-accredited zoo. The hatchlings and most adults are housed in off-exhibit areas of the zoos, but one adult female is on exhibit at the Animals in Our Lives building at the Prospect Park Zoo.
WCS is breeding Chinese big-headed turtles and other endangered turtle species to build assurance colonies with the purpose of maintaining a genetically viable population until conservationists are able to stabilize wild populations. The development of assurance colonies, along with work in nature, are part of WCS's widespread conservation effort to save turtles.
Chinese big-headed turtles are native to China, Cambodia, Laos, Myanmar, Thailand and Vietnam. The species is classified as Endangered by the International Union for the Conservation of Nature (IUCN). Their population is declining due to trade demand across its Asian range countries. In zoos, specific environmental and climatic conditions need to be manipulated in order to stimulate Chinese big-headed turtles to breed. Zoo experts were able to successfully recreate and document these conditions in the zoo's propagation facilities, providing a road map for other organizations to propagate this species.
Additionally, complex husbandry techniques were fine tuned to promote breeding and successful incubation of the eggs. Before the breeding season, adults are isolated and placed in enclosures with environmental conditions that mimic the annual environmental cycles they would experience in the wild. These environmental cycles are important to the regular reproductive functions of the species. Room temperatures and lighting are adjusted depending on the time of year – colder and darker in the fall and winter, warmer and lighter in the spring and summer. During their "winter" the turtles hibernate. After awaking, males are introduced to females.
Said Denise McClean, Director of the WCS Prospect Park Zoo: "With so many of the world's freshwater turtles and tortoises facing extinction, these hatchlings represent significant progress for the conservation of the species. The science could help expand breeding programs to other facilities and can be useful to conservation work in the field."
There are approximately 330 species of freshwater turtles and tortoises, half of which are threatened with extinction due to illegal trade and habitat loss. WCS strives to alleviate threats to highly endangered turtles around the world by working closely with relevant governments to react rapidly in nations that are centers of turtle diversity, including the big-headed turtle's native range.
In addition to its efforts on terrestrial and freshwater turtles, WCS marine programs work to save sea turtles all over the world.
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