No status assigned in Minnesota.
The Mudpuppy is Minnesota's largest salamander reaching lengths of 13-16 inches. They are also our only salamander that is entirely aquatic their whole lives. Adults are brown, reddish-brown, or gray above with varying numbers and sizes of black spots. Ventrally, they are gray with dark mottling. They have four toes on the front and back feet. Long, feathery red gills are very obvious on the sides of the head. The head is large and flattened. They have small, lidless eyes that do not bulge out from the head like our other salamanders. The tail is laterally compressed with fins above and below that give the tail a paddle-like look. This salamander is extremely slimy and it is nearly impossible to hold on to a specimen with bare hands.
The mudpuppy (Necturus maculosus maculosus) is the only subspecies found in Minnesota.
Mudpuppies are found in eastern Minnesota along the Mississippi and St. Croix Rivers and some associated tributaries. They extend west through the state via the Minnesota River and in rivers and lakes associated with the Red River in northwestern Minnesota.
Mudpuppies are found in medium to large rivers and lakes with all types of bottoms. In clear, fast moving rivers and streams, mudpuppies have small, compressed gills. In warm or slow moving rivers and lakes they have big, bushy gills. They take refuge under sunken objects such as rocks, logs, boards, and other debris. They have been taken at depths of 70 feet in large lakes.
Mudpuppies are active year round. They are mainly nocturnal. They breed in fall and early winter. 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. I have seen a mother and many newly hatched mudpuppies in a crushed minnow bucket in a lake in Ottertail County in June. 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. This may take five years (Bishop, 1941). Fishermen often catch mudpuppies while they are fishing. Many believe them to be poisonous and will cut their line before touching them. This is false; mudpuppies are not poisonous, but large specimens may give a good bite if handled roughly.
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.