Platysternidae

Platysternidae is a family of turtles containing a single living species, the big-headed turtle, Platysternon megacephalum, found in Cambodia, China, Laos, Myanmar, Thailand and Vietnam. The species is named for its disproportionately large head, which it cannot withdraw into its shell, and it defends itself instead with an armored head and a sharp beak. Big-headed turtles inhabit fast-flowing streams and waterfalls in rocky areas, are not strong swimmers, and readily climb over obstacles using the tail as a prop; the species is listed as Critically Endangered.