At 25-30 cm, this is Ontario's largest salamander.
The mudpuppy has a reddish-brown back, with black spots scattered over the body. Juveniles have brightly colored yellow stripes on their body that fade with age.
This salamander retains its external gills throughout its life. These red gills are feathery and are most obvious when fully opened.
This salamander is very slippery and is almost impossible to hold with bare hands.
The mudpuppy is always found in water and frequents the bottom of riverside marshes, weedy ponds, and lakes.
Because oxygen is absorbed from the water through external gills, the mudpuppy is restricted to permanent bodies of water. The lungs are poorly supplied with blood and have a minor role in respiration. They are used mostly for gulping air at the surface of warm, muddy water that is low in oxygen.
The mudpuppy hides in weeds or under rocks during the day and emerges at night to feed on crayfish, tadpoles, worms, fish, and aquatic insects.
Breeding occurs in the fall, but the eggs are not laid until April or May of the following year.