The Family Proteidae is a group of salamanders that are commonly referred to as "waterdogs" or "mudpuppies". Other slang names for these aquatic amphibians include "water puppies" and "mud eels". The Proteidae family includes five different genera: Necturus, Proteus, Lissotriton, Laotriton, and Paralichthys. While different members of this family can vary in terms of their appearance and behaviors, all Proteidae have several qualities in common, including external gills and four toes on their front legs. Some species in this family are found worldwide, while others are found only in certain parts of North America and Europe.