Previously considered a distinctfamily placed on occasion in "Kinosternoidea", it was later moved to theEmydidae. This, as well as the subfamily and thegenusPlatysternon, aremonotypic.
The big-headed turtle is named after its disproportionately large head which leads to an inability to retreat into itsshell. In order to protect itself it instead has an armored head and sharp beak.[5]
The big-headed turtle is known to readily climb over obstacles in and around rivers and fast streams, using its tail as a prop to extend the reach of its strongclaws. It also uses its beak to assist in climbing.[6] It has been reported to climb trees and bushes. These turtles generally move more during the night, and are not prone to moving long distances. They have a general daily range of 0-89.6m and males tend to move further than the females in this species.[7] They are not strong swimmers, and when swimming, this species occasionally arches its tail in the manner of ascorpion.[6] The big-headed turtle cannot pull its head in its shell. That being the case, it will not hesitate to use its powerful jaws to defend itself. Its diet consists offish,snails andworms.[8] It also tends to eatfruits like theMachilus spp., as well asinsects,crabs andmollusks.[9]
Originally assumed to be strictlycarnivorous, this appears to be anopportunistic feeder with a significant shift towardsomnivory orherbivory. Using fecal matter, big-headed turtles are found to consume fruits (Machilus andTurpinia arguta), terrestrial insect adults/larva and aquatic larva (Coleoptera,Homoptera,Hymenoptera,Isoptera,Lepidoptera,Mantodea,Orthoptera,Diptera,Ephemeroptera,Odonata andTricoptera), mollusks (Sulcospira hainanensis), frogs, rodents, and freshwater crabs. Their eating behavior changes depending on the environmental conditions, but predominantly consume fruits. Seeds partially digested were found to have increased germination success after turtle excretion, possibly connecting theirfrugivore habits to environmental conditions.[10]
The big-headed turtle is found quite frequently inillegal wildlife trade.[5] It is readily consumed inAsia and is frequently a market item. Hunters capture them on lines with baited straight pins, so this species is rapidly disappearing in the wild.[11] The species is also threatened by its use in thepet trade.[1]
