The female lays up to 100 eggs in late spring and summer. She digs a cavity under an object such as a rock or log and turns upside down to attach her eggs to the roof of her nest. She guards them until they hatch and may stay with the young a while after they hatch. The young are very small and are marked with one yellow dorsolateral stripe down each side of the back. The pattern changes relatively slowly until they look like adults.
Fishermen often catch mudpuppies while they are fishing.
Many believe them to be poisonous and will cut their line before touching them. Sightings of mudpuppies should be reported to the IA DNR or us. Food Mudpuppies will eat anything they can catch. Crustaceans, insects, worms, fish, fish eggs, salamanders, and crayfish are all reported foods. Mudpuppies probably do not have keen eyesight and rely heavily upon olfactory cues to find their prey.