Description and Distribution
The Chinese Water Dragon (Physignatus Cocincinus) is a large arboreal lizard that lives in southeastern Asia, specifically China, Vietnam, Cambodia and Laos. The exact range of the animal is unknown. They are the second largest Asian lizards, second to the sailfin lizard.
The water dragon's body is covered in fine green scales, sometimes with blue or yellow streaks on them, and often with a few black scales. Their throats have rainbow-like colour formations, with pinks, blues, whites, turquoises, yellows and the occasional black scale. It's very easy to distinguish between individual dragons, since they all have different colour patterns on their scales. While not comparable to chameleons or anoles, they can in fact change their colour, which is an indicator of the animal's emotional state. Drab, brownish green means 'bad', bright green means 'good'. There are probably many subtleties that you have to be a water dragon yourself to understand.
Water Dragon vs. Green Iguana
They slightly resemble the more well-known green iguanas of the Americas, in that both are excellent swimmers and climbers, they both live in trees, they both have very long tails (at least 2/3 of a water dragon's length is tail) that they whip at predators as a defensive weapon, and that they're both big green lizards.
The similarity ends there though. The green iguana is a herbivore or vegetarian, whereas the dragon is a pure carnivore who primarily eats small fish, insects, smaller lizards, and small mammals. Water dragons are also significantly smaller than green iguanas -- an adult male iguana grows to over 180 cm (6 ft) in length, whereas water dragons don't often exceed a meter. Their body shape is also more upright and "triangular" than that of the iguana, and they can in fact run bipedally for short periods of time. There are also many differences in behaviour, water dragons tend to be a lot less aggressive than iguanas, and are usually much easier to tame.
Water dragons tend to be bright and curious, and they love being allowed to roam free and explore, making them popular reptile pets (and as an added bonus to the keeper, they will hunt insects and arachnids, if any are nearby -- make sure your room is dragon-proofed before letting one loose though, they are more curious than they are careful). They quickly get used to human contact, and some of them even become actively contact-seeking with the humans they trust. One of the water dragons I have kept loved to sit on my shoulder while I wrote code, and sometimes nudged my neck with her snout until I stopped whatever I was doing and stroked her carefully on the back of her neck. Perhaps those sorts of little quirks are why they are sometimes likened to tiny, reptilian, not-too-smart cats, they certainly possess some of the same traits. Most captive-bred dragons are quite trusting, peaceful and docile (wild-caught ones are a lot more skittish, although water dragons are rarely aggressive -- they tend to flee or put up a show instead of fighting). Like bearded dragons and dogs, they transfer much of their social behaviour to humans if kept in captivity, although wild-caught dragons tend to retain a need for hanging out with other dragons.
The water dragon is not an endangered or threatened species.