In spite of this giant salamanders are significantly less known by the large public than their analogous in reptiles' world, the Komodo Dragons. The family Cryptobranchoide has two genus with one (Cryptobabranchus alleganiensis) respectively two species (Andrias davidianus, A. japonicus). A. japonicus is restricted to Japan, A. davidianus in China while C. alleganiensis lives in North America. A. japonicus lives in the cold fast flowing mountain streams and smaller rivers of Kyushu Island and western Honshu in Japan. Thirty million years old fossilized Giant Salamanders have been found in Europe as well. The giant salamanders are considered true "biological relicts". Leading scientists admit that they did not evolve in the last 20-30 million years. For scientist these rather primitive salamanders are clues to the understanding of the roots of Earth's biodiversity. As their way of life has not changed significantly students of Giant Salamanders may provide insightful information on the ecosystems that existed million years ago.
In spite of their relatively large body size and somewhat frightening looks they are totally harmless to humans. Unfortunately the opposite is not true. Both A. japonicus and A. davidianus are threatened with extinction. Until the early 50's Japanese Giant Salamanders were an important protein source for the local population. They were caught by fishing rod and were considered a true delicatessen. Accelerated degradation of natural habitats represents today a bigger threat to the Giant Salamanders that hunting, or illegal killing by fishermen. Being old species Giant Salamanders might lost their genetical plasticity. It is well known that the older a species is the harder it adapts to new conditions.
