Scientific Classification
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Reptilia
ORDER: Testudines
FAMILY: Cryptodira
GENUS: Platysternon
SPECIES: Platysternon megacephalu
Conservation Status
The name says it all, the big-headed turtle is most famous for its unusually large head. It is so large that it cannot pull it into its shell for safety like most other turtle or tortoise species.
To protect against danger, they have developed an armored head. Plates called scutes on the top of their head that are made from keratin. It’s the same protein that makes up fingernails and is also the same material that covers their shell. Underneath the keratin plate is a heavily armored skull. To top it off, as an added defense, they have incredibly strong jaws much like a snapping turtle and will use them to defend themselves.
When it retracts its head it wont fit into its shell like normal turtles but its neck tucks nicely away only exposing their armored head and shell.
They also have a very long tail and a relatively flattened body. The reason for the flat shell is so they can keep a low and streamlined profile in the water so they aren’t swept away with the current.
Their extraordinarily long tail sometimes measures as long as their shell and can act like an extra limb. They use it to help them balance and navigate through the terrain while they use their heads and strong jaws to bite objects like roots or plants to move them throughout their surroundings.
The big-headed turtle is found in all of Southeast Asia and China, which includes Cambodia, Hong Kong, Laos, Northern Burma (Myanmar), Northern and Western Thailand, and Northern Vietnam.
They are found in clean, cool mountain brooks or steams that are unpolluted and usually 5-6 feet wide and less than a foot deep. In Thailand, some of the streams dry up seasonally and the turtles will travel over land to find new sources of water.
As of now, the population of big-headed turtles is unknown. What is known is numbers are declining due to intensive and unregulated hunting. And there is much need for research too since surprisingly few scientists are studying these amazing turtles.
The reason behind that huge skull lies in what the big-head turtle eats. They are nocturnal and feed primarily at night on hard-shelled creatures like crayfish, snails, and mussels, and also fish. It is unknown whether or not they have always been nocturnal, as some other endangered animals like the big-headed turtle were originally active by day, but due to pressure from humans, changed their habits to avoid detection at night.
In order to crush the hard shells of their prey, they have developed immensely strong bites and massive heads much like snapping turtles to support well-developed muscles and a hooked beak. The main difference between them and a snapping turtle is their bodies are much smaller.
Almost nothing is know about the reproductive habits of big-headed turtles in the wild. Like most turtles, they are likely long-lived. The only documented age of a captive specimen is roughly 15 years, though it’s expected they live longer in the wild.
Despite knowing very little about their reproduction some successful captive breeding programs have sprung up in recent years. The Wildlife Conservation Societies Prospect Park Zoo with a partnership with the Turtle Survival Alliance successfully bred a pair of big-headed turtles which gave rise to 13 hatchlings as of 2013.
They discovered since most of this species lives in temperate areas that experience seasonal variations, they needed to replicate these settings as close as possible to stimulate the turtle’s natural reproductive cycle.
They carefully controlled ambient temperature, lighting, and diet. Five weeks away from the hibernation period, they withheld food and started reducing the temperature and light to stimulate hibernation in the turtles around November. Five weeks may sound like a long time, but ectothermic or cold-blooded animals like turtles can go very long without food.
After several months of hibernation. They slowly reversed the settings in April and increased the light and temperature and the turtles slowly emerged. They then introduced the male and female turtles together and they began to mate after several different sessions.
After about a week the female was seen digging and burying herself in preparation to lay eggs. She laid about 5 small white eggs that were closely monitored until they were ready to hatch about 100 days later.
Interestingly, the gender of turtles is determined by temperature and not genetics from the mother and father like humans. It is officially called temperature-dependent sex determination. If the temperature is just right, it produces an equal number of males and females, but if it is too hot or too cold, then it will produce more females.
Since they are poor swimmers and the streams where they live can dry up during parts of the year, they are also good climbers and use a combination of tools to help them get across rocky terrain in the forest.
