English name: Malayan Snail-eating Turtle (aka “Rice-field Terrapin”)
Scientific name: Malayemys macrocephala (previously Malayemys subtrijuga)
Thai name: Tao Na
Description: Shell is up to 30cm long. Shell is brown with three distinct ridges, or “keels”, along the top. Edge and bottom of shell are yellowish. Head is black with white or yellow lines that curve around the eye on top and bottom.
Similar Species: The Southeast Asian Box Turtle has a domed shell, lacks the triple shell ridges, and has yellow head stripes that go straight across the head both above and into the eye rather than curving around it.
Black Marsh Turtle is all black, lacks the light stripes on the head, and only has one keel on top of its shell.
Red-eared Slider lacks the triple shell ridges and has a red spot behind its eye.
The Mekong Box Turtle is a very similar related species found in the Mekong River Basin. It can be identified by having at least 6 nasal stripes and an infraorbital stripe that goes well past the loreal seam
Habitat: This turtle is found in slow-moving bodies of water with muddy bottoms and lots of vegetation, such as marshes, swamps, rice paddies, and irrigation canals. In Bangkok it is most often found in the slow-moving canals of city parks, but I have also found it in the ponds of undeveloped areas.
Place it the ecosystem: The Malayan Snail-eating Turtle eats snails almost exclusively. On occasion it will also eat mussels, crabs, shrimp, and insects. It is preyed upon by monitors, and the young can be preyed on by large fish, snakes, wading birds, and crows.
Danger to humans: There is a small risk of salmonella contamination if the feces of the turtle reach the mouth of a young child (most often occurs from handling pet turtles). To be safe it is recommended that you wash your hands after handling any turtle. Otherwise these turtles are completely harmless.
Conservation status and threats: The Malayan Snail-eating Turtle is subject to habitat destruction in its native river valleys and is under pressure from collection for food markets and Chinese medicine. It is also collected in smaller numbers for the pet trade and for “merit release”. Habitat deterioration, pesticides, and fishing nets may also affect populations. While it is still common in Thailand, it is becoming rare in neighboring counties and outside of Thailand it has been assessed as “Vulnerable” by the IUCN Red List of Threatened Species. It is also listed in CITES Appendix II.
Interesting facts: The Malayan Snail-eating Turtle has a large head and strong jaws, which enables it to crush the shells of snails. Due to its unusual diet, among other factors, the Malayan Snail-eating Turtle tends to do poorly in captivity and does not make a good pet.
The Malayan Snail-eating Turtle is probably the Thai turtle species most often used in the practice of “merit release”, where turtles and other animals are released into nature in order to “make merit”. Sadly, many such turtles are released into inappropriate or overcrowded habitats (such as decorative park and temple ponds) and end up dying after a long period of starvation or overcompetition. Other released turtles spread diseases that they caught in captivity into wild populations, thereby killing many more turtles. More information on turtle release and merit-making can be found at the Buddhist Merit-making Turtle Release Checklist.
IUCN/SSC Tortoise and Freshwater Turtle Specialist Group: Malayemys macrocephala
Wikipedia: Malayemys macrocephala
The Reptile Database: Malayemys macrocephala
Geographic Variation and Systematics in the South-East Asian Turtles of the Genus Malayemys
Buddhist Merit-making Turtle Release Checklist
A Field Guide to the Reptiles of South-East Asia
The Turtles of Thailand
Turtles of the World