Chinese Crocodile Lizard

No, despite the name and the resemblance. It is a true lizard, and its common name comes purely from the two rows of large, raised, ridged scales running along the top of its thick tail, which give the tail a knobbly, armoured, crocodile-like profile, and from its semi-aquatic, ambush-hunting lifestyle, which superficially recalls how a crocodile lurks in water. Crocodilians are a completely separate group of reptiles, more closely related to birds than to lizards, so the similarity is a case of convergent appearance rather than any close evolutionary relationship.

It is the sole surviving species of the family Shinisauridae, a lineage of lizards whose fossil relatives are known from tens of millions of years ago across a much wider area including Europe and North America, all of which have since gone extinct. Because this single species is the only remaining representative of an otherwise vanished branch of the reptile family tree, and because its body form has changed relatively little from those ancient relatives, it is often described as a living fossil, and it is of particular interest to scientists studying the early evolution and relationships of lizards.

It regularly enters a state of near-total stillness, remaining motionless on a branch or rock for long periods, often with its eyes closed, sometimes even during daylight hours, which can make it appear to be deeply asleep. This behaviour, combined with its slow, deliberate movements when active, gave rise to a Chinese common name that translates roughly as the lizard of great sleepiness. Biologically, these long periods of inactivity are an energy-conserving strategy suited to a cool-climate ambush predator that does not need to move much to feed and benefits from staying still and inconspicuous both to avoid predators and to wait for prey.

Its wild population has fallen to only a few thousand mature individuals scattered across a handful of isolated forest-stream sites in southern China and northern Vietnam. The main pressures are the loss and degradation of its very specific habitat, cool, clean, shaded streams in intact subtropical forest, through logging, agriculture, dam and reservoir construction, and water pollution, together with heavy collection of wild lizards for the international exotic pet trade and for use in traditional medicine. Because populations are small, fragmented, and slow to grow, the species has been assessed as Endangered and is legally protected, with captive breeding programmes established as an insurance against extinction in the wild.