Pictured above: These two pictures are of captive specimens owned by the National Aquarium in Duluth, MN. Look at the individual on the right (top picture). You can see the external gills protruding from the side of his head. Also, notice how small their eyes are. In fact, they are barely visible.
To view more pictures of this salamander, visit www.herpnet.net
Description: The Mudpuppy is the largest salamander species (terrestrial or aquatic) residing in Wisconsin, reaching adult lengths of 11 to 15 inches. They are also the only fully aquatic salamander species in the state (note: although the Central Newt is largely aquatic, it still has terrestrial stages). Dorsally, they are brownish or gray with many dark flecks and spots. Their heads are flat and wide, with eyes that are barely visible, while their legs are somewhat stubby. They have dorsally-ventrally wide, rudder-like tails, which aid in swimming. Mudpuppies also have large, bushy external gills, which are usually red. This can occasionally lead to them being mistaken for larval Tiger Salamanders (or vice versa), however, the gills of Mudpuppies are much bushier and brighter red in color.
Mudpuppies are incredibly slimy. Vogt (1981) describes them as very difficult to hold, comparing them to a "greased hotdog" in the hands of humans.
Habitat/Ecology: Mudpuppies are reported to favor large water bodies with moderate currents. They are frequently found along the shorelines of lakes, and in rivers among rocks and stone rubble. It has been reported that they are often found below dams and at depths of up to 30 m (Vogt 1981).
They will consume a large range of aquatic organisms including; small fish, amphibians and their larvae, as well as aquatic insects and worms. Mudpuppies breed later than any amphibian in the state (late October and November), however, egg deposition does not occur until the following spring. Females are reported to deposit eggs (approximately 100) on the lower surfaces of rocks in underwater cavities. It is said that the female will remain near the eggs for two months, guarding and aerating them.
Remarks: Occasionally referred to as "water dogs", these salamanders were once commonly used as bait by fisherman. Christoffel et al. (2001) lists them as being found throughout the state, and they are said to be common in areas where the habitat is suitable.
There are several reports of Mudpuppies being attracted to light, and fisherman can supposedly bring them to the surface with their lanterns while night-fishing. However, because they are completely aquatic, they are seldom encountered. Mudpuppies are active throughout the year, and I have received reports from ice fisherman who accidentally caught them during the winter.
I have never encountered a Mudpuppy within Wisconsin and most of the information presented here is from other sources. I know that they are relatively abundant in areas of the Mississippi River but I have not been lucky enough to find one.