The so-called water dragons are large diurnal arboreal agamid lizards in the genus Physignathus, which includes Physignathus cocincinus, the Green or Chinese Water Dragon, and Physignathus lesueurii, the Australian Water Dragon. They are sometimes kept as pets, especially P. cocincinus, though a full-grown male of that species will measure about three feet (1 meter) total length and thus requires a fairly large enclosure for proper care.
P. cocincinus is found throughout South-East Asia, in Thailand, Cambodia, Vietnam and south China. These lizards are semi-aquatic, using their laterally-compressed tails to propel them when swimming. They are able to remain submerged for long periods of time. Like many lizards, Physiognathus have a parietal eye, a light-sensitive “third eye” located in the top of the head.