by Terry Messmer and Forrest B. Lee
The mudpuppy is a large aquatic salamander that, unlike other salamanders, spends its entire life in water. Adult mud puppies are from 8 to 15 inches long. The background color of the upperside is gray or rust brown speckled with scattered indistinct blue-gray spots. The underside is light gray and sometimes has dark spots. The head is broad and flattened with a squarish snout, small eyes, and a large mouth. It has a stout body and tail with limbs that have four toes without claws. Three pairs of red feathery gills are on each side of the neck. These are constantly in motion. The fins of the tail are often tinged with orange. The skin is smooth, moist, and exceedingly slimy. Like other amphibians its body temperature varies with the temperature of the surrounding environment.
Most amphibians begin life in water and later undergo changes in body structure that enable them to also live on land. Mud puppies go through only part of this change. They acquire the four limbs, but retain the gills instead of developing nostrils and lungs that would enable them to five out of water.
The mudpuppy has been found in North Dakota only in the Red River near Grand Forks. Its main range in North America is farther east in the drainage systems of the Mississippi River, Great Lakes, and upper Hudson River.
The mudpuppy is a bottom dweller that spends its entire life in water. It occurs mostly in larger permanent lakes and streams and in a variety of habitats ranging from the clear waters of the Great Lakes to weed-choked bottoms of smaller aquatic environments. They have been captured at depths exceeding 120 feet. Mudpuppies are active all year long. Mudpuppies are nocturnal in clear water but are active all day in muddy water.
Mudpuppies mate mostly in late fall and winter with an elaborate strutting courtship ceremony led by the male. During the performance the male deposits jelly-like masses containing sperm. Then the female maneuvers over the sperm capsules and takes them up into her cloaca. The eggs are the size of peas and are laid in latespring or early summer. The incubation period varies from one to two months depending on the temperature of the water. The female guards the nest during the two-month incubation period. The eggs are usually laid in 2 to 4 feet of water in a cavity excavated under stones or sunken logs or boards. They are attached to the under-surface of such objects by gelatinous stalks, one per egg, in groups of 50 to 100. The larval young grow slowly and some do not mature to the adult form with limbs until the fifth year when they are about 8 inches long.
The mudpuppy has a voracious appetite and eats a large variety of foods that enables it to survive under diverse conditions. The food of the larval form is largely microscopic organisms at first, but later larger forms of aquatic life are consumed. These include worms, water insects, crayfish, mollusks, frogs, fish eggs, and small fishes.
References
Black, J.H. 1970. Amphibians of Montana. Montana Fish and Game Dept., Helena. 31 p.
Breckenridge, W.J. 1944. Reptiles and Amphibians of Minnesota. Univ. Minnesota Press, Minneapolis. 202 p.
National Audubon Societ,v. 1979. The Audubon Societ,v field guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc. New York. 743 p.