Giant salamanders have an interesting life cycle. They lay large clutches of sizable, yolky eggs under rocks in the headwaters of clear water streams. Eggs hatch after a several month incubation into stream-adapted larvae that have well developed limbs, a depressed body, and a tail fin that extends only to the base of the tail. The larvae live for at least 2 and perhaps as long as 4 years. They grow to a large size, some as large as the largest known adults. Occasionally larvae become reproductive, but more typically they metamorphose into the adult form.
Diet is most likely similar to related Pacific giant salamanders that feed on aquatic invertebrates, with a shift towards larger prey items with growth. Pacific giant salamanders have an arched posture and will release toxins when disturbed.