[1] The Japanese giant salamander (Andrias japonicus) reaches up to 1.44 m (4.7 ft) in length, feeds at night on fish and crustaceans, and has been known to live for more than 50 years in captivity.

Clade Pancryptobrancha (Cryptobranchidae + Ukrainurus) The following phylogeny is based on Vasilyan et al. (2013):[7] †Ukrainurus Cryptobranchus †Aviturus †Zaissanurus Andrias The well-represented Cretaceous Eoscapherpeton was not phylogenetically placed.

These folds help increase the animals' surface area, allowing them to absorb more oxygen from the water as the adults lacks gills and have poorly developed lungs.

They have paedomorphic traits, meaning their metamorphosis from the larval stage is incomplete, so they lack eyelids and the adults retain gill slits (open in the hellbender, closed in Andrias).

As they have poor eyesight, they use sensory nodes on their heads and bodies to detect minute changes in water pressure, enabling them to find their prey.

Lacking the stereotypical courtship behaviors found in other species, the male fertilizes the eggs externally by releasing his sperm onto them, and then guards them for at least three months, until they hatch.

Scientists at Hiroshima City Asa Zoological Park in Japan have recently discovered the male salamander will spawn with more than one female in his den.

[12] Extant species in the family Cryptobranchidae are the modern-day members of a lineage that extends back tens of millions of years.

[15] As the fossil record for the Cryptobranchidae shows an Asian origin for the family, how these salamanders made it to the eastern US has been a point of scientific interest.

In doing so, both the genus, Andrias (which means "image of man"), and the specific name, scheuchzeri, ended up honouring Scheuchzer and his beliefs.