Females lay long, paired strings of several hundred eggs which are fertilized externally by the male. Males guard the eggs until they hatch in 2-3 months after laying. Fossils indicate that Cryptobranchus formerly occurred also in western North America. Asian salamanders of the genus Andrias are used for food and are now considered highly endangered. These large, aquatic salamanders have dorsoventrally flattened bodies except on the tail, which is laterally compressed and finlike.
Limbs are short but massive and sturdy.
Folds are present in the skin, which forms flaps along the lateral margins of the body. Eyes are small and lack eyelids. Larvae have caudal fins and short, external gills. They live under rocks on the bottoms of fast-flowing streams and rivers. The morphological characters given below are the ones standardly used to diagnose the salamander family Cryptobranchidae and to assess its phylogenetic relationships to other salamanders.