The mudpuppy (Necturus maculosus) is the only completely aquatic salamander in Canada. It is also the largest salamander species in the country.
Mudpuppies are grey to rusty brown on top with dark blue spots and a grey belly. They have red, feathery external gills and only four toes on both the front and hind feet. Compared to the eyes of other salamanders, the mudpuppy’s eyes are relatively small with respect to the size of its head. Juvenile mudpuppies range in colour from orange to black with longitudinal yellow stripes. The mudpuppy can grow to almost 50 centimetres in length, including the tail.
Given their large size, mudpuppies cannot be confused with any other salamander. Even larval mudpuppies are typically at least twice as large as the larvae of any other salamander.
Lakes, rivers, streams and other large bodies of water are prime mudpuppy habitat. They have been found in muddy, weed-choked streams and up to 30 metres below the surface of Lake Michigan. During the day, mudpuppies usually hide under rocks.
View an interactive map of the known ranges of mudpuppies in Ontario.
The mudpuppy breeds in the spring. In May or June, the female lays 30 to 190 eggs, one at a time, on the underside of submerged rocks or logs. The female guards the eggs until they hatch, in two months. The larvae are approximately two centimetres long when they hatch and take four to six years to transform into adult salamanders.
Mudpuppies are primarily nocturnal (most active at night). They are carnivorous and forage year-round for worms, fish eggs, aquatic insects, crayfish and small fish. Individuals that survive to adulthood have few natural enemies and can live for over 30 years.
Other names: common mudpuppy, waterdog
Threats and Trends
Poor water quality is a perennial threat to many animals, but especially to totally aquatic ones like the mudpuppy. Research on mudpuppies in the St. Lawrence River found high levels of pollutants, such as PCBs and organochlorine pesticides in their eggs. At a site along the St. Lawrence that has high levels of PCBs, over 60 percent of the mudpuppies examined had limb deformities, such as missing or extra toes.
Anglers occasionally catch mudpuppies, especially in the winter, possibly because ice-fishing for whitefish (a bottom feeder) brings baited hooks down to the mudpuppy’s domain. Other mechanical intrusions such as dredging, commercial fishing nets and boat propellers kill mudpuppies. Despite these threats, the mudpuppy is not known to be in significant decline.
Current Status and Protection
The mudpuppy is currently listed as Not at Risk by the Committee on the Status of Endangered Wildlife in Canada and Not at Risk under the Ontario Endangered Species Act, 2007 and as having No Schedule, No Status under the federal Species at Risk Act. The International Union for Conservation of Nature lists the global status of the mudpuppy as Least Concern. The species’ status was confirmed in January 2010.
Learn more about reptile and amphibian conservation and what you can do to help these species on our Reptile and Amphibian Stewardship page.