What is a mud puppy?

A mud puppy is a salamander, specifically an aquatic salamander commonly known as the mudpuppy. The best-known species is the common mudpuppy, Necturus maculosus, a member of the salamander family Proteidae.

Unlike many salamanders, mudpuppies spend their entire lives underwater. They retain feathery external gills into adulthood, a condition associated with paedomorphosis, so they do not transform into a typical land-dwelling adult form. Their rusty-brown bodies are often marked with dark spots, and they are mainly active at night in lakes, rivers, streams, and ponds.

Mudpuppies live in parts of eastern North America, including southern Canada and areas of the United States. They eat aquatic prey such as insects, worms, mollusks, crayfish, and small fish. The name can cause confusion because “mudpuppy” is also used in the common name of the salamander mussel, a separate bivalve whose larvae use mudpuppy gills as a host. In ordinary zoology trivia, however, “mud puppy” refers to the salamander.