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Mudpuppy © Scott Gillingwater

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, although lengths of approximately 30 cm are more typical.

Mudpuppy © Nick Cairns

Similar Species

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.

Mudpuppy © Joe Crowley


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 reach sexual maturity. These salamanders do not undergo metamorphosis into a terrestrial form, and instead remain aquatic throughout their lifespan.

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

Mudpuppies © Nick Cairns

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.

Mudpuppy © Nick Cairns

Current Status and Protection

The mudpuppy was assessed as Not at Risk by the Committee on the Status of Endangered Wildlife in Canada in 2000, and has not been assessed by the Committee on the Status of Species at Risk in Ontario.. The species has No Schedule and 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 August 2015.

Learn more about reptile and amphibian conservation and what you can do to help these species on our Reptile and Amphibian Stewardship page.

Mudpuppy © Scott Gillingwater

What You Can Do

  • Report a sighting
  • Get involved in reptile and amphibian conservation on your property, on the road and in your community
  • Donate to support reptile and amphibian conservation
  • Watch for reptiles and amphibians on the road
  • Don’t release pet reptiles and amphibians into the wild
  • Read more about the mudpuppy in the Ontario Reptile and Amphibians Atlas publication.
Mudpuppy © Ryan Wolfe