General Description: This is a large, fully aquatic salamander with adults averaging 30 cm total length. Adults and juveniles possess external gills along the sides of the head. Unlike tiger salamanders that eventually lose external gills and undergo metamorphosis to become terrestrial adults, mudpuppies remain fully aquatic. A dark stripe extends through the eye to the gills. Adults have dorsal patterning consisting of mottled black spots on a gray or tan background. Juveniles have a dark dorsal band down the length of the body which is bordered by a light yellow stripe on either side. The ventral side is light and may have slight mottling. The tail is laterally compressed. This species is often misidentified as juvenile tiger salamanders (also confusingly called mudpuppies or waterdogs) due to the presence of external gills; however, mudpuppies only have four digits on the hind limbs while tiger salamanders have five. Diagnostic characters include the presence of external gills and hind limbs with four digits (Eastern Tiger Salamanders and Western Tiger Salamanders have five digits on hind limbs).
Behavior: This is a nocturnal salamander, often spending much of the day under cover and emerging at night to forage. Diet consists of a variety of aquatic invertebrates, crustaceans, and fish.
Reproduction: Females may lay 75–100 eggs per season. Fertilization is internal and females will construct and guard nests with eggs.
Habitat: Large, permanent, water bodies such as canals, bays, large streams, and lakes.
Species Range: This species is found across a large region of North America west of the Appalachian Mountains, through the Great Lakes region, and as far west as eastern North Dakota and Oklahoma.
South Dakota Range: This species has been reported from the northeast corner of South Dakota in Day, Marshall, and Roberts counties. Observations of this species have been reported in the 1920s from Waubay Lake (Day Co.), and Big Stone Lake (Roberts Co.) and in 1972 from Buffalo Lakes (Marshall Co.). The most recently collected individual was from Hartford Beach State Park on Big Stone Lake in 1984 (see photo below). This individual now represents the only known vouchered specimen of this species from South Dakota. It is unclear if the records from Day and Marshall counties are of a Mudpuppy or were misidentified larval tiger salamanders.
South Dakota Status: This species is listed on the South Dakota Natural Heritage Program. Any sightings of this species should be reported to South Dakota Game, Fish and Parks (report observation). This species is classified as SH (historically known) because it has not been observed in over 30 years. Renewed efforts to determine if this species is still present in South Dakota began in 2013 and are ongoing.
Account written by Drew R. Davis