Mud Puppy, a salamander that lives in lakes and rivers in the eastern United States. An adult mud puppy is 8 to 17 inches (20 to 43 cm) long. It is brownish or almost black above, with a dark-spotted, pale underside. The rectangular head and body are flattened. The tail fins are often reddish. Each of the four feet has four toes. Dark-red gills wave like plumes outside the gill openings on the neck.

Mud puppies feed on snails, insects, and worms on the muddy bottom. They are sometimes caught accidentally by fishermen. In the spring the female lays 60 to 70 eggs in shallow water, where they hatch in about seven weeks. The young resemble the parents.

The mud puppy is Necturus maculosus of the family Proteidae.