Conservation Corner: Amphiuma

Published 3:16 pm Tuesday, July 8, 2025

This curiously ugly, snake-like salamander is a genus of aquatic salamanders and can be found in the southeastern part of the United States. There are three different species of amphiuma that can measure anywhere between 8.5 inches to 46 inches in length. Although incorrect, amphiuma are often referred to as “Congo snakes,” or “conger eels” because of their elongated bodies and four very small, unseen legs.

Amphiumas have a lateral line visible on the sides of their bodies which aids in detecting movement and hunting their prey. Interestingly, amphiumas have one of the largest amounts of DNA in the living world–nearly 25 times that of a human.

Residing in the stagnant waters of swamps, ponds, lakes, wetlands, and bayous, amphiumas often hide in heavy vegetation and burrow during the day and come out at night to hunt. Although the amphiuma is known to eat nearly anything they can catch, some of their most common prey include worms, snakes, snails, crustaceans, small fish, tadpoles, frogs, and even other amphiumas.

Predators are the largest threat to amphiumas. These include mud snakes, cottonmouths, and alligators.

Though the courtship and reproductive process of the amphiuma is not well documented, we do know that internal fertilization occurs through the direct transfer of the spermatophore. The female lays a clutch of 40 to 350 eggs in a burrow or under debris near the edge of water, in wet mud. Oftentimes, she remains coiled around them for the 4- to 5-month incubation period. Once hatched, the larvae have external gills that will disappear after 4 months when the lungs begin to work. However, one pair of gill slits is retained and never disappears.

Although most amphiumas share many of the same traits, there are three different amphiuma species–distinguished by the number of toes on their feet.

The one-toed amphiuma has one digit on each foot and has limbs and a cone-shaped head that are proportionately shorter than the other two species. Additionally, the one-toed amphiuma lacks costal (rib) grooves while the other two species have 55 to 65 costal grooves. These amphiumas are typically dark gray or purplish brown on the back and belly. It is the smallest of the three species.

The two-toed amphiuma has two, and sometimes three, toes on each foot. The two-toed amphiuma, unlike other salamanders, is not mute. They give a clear whistle when disturbed. Bluish black in color, the two-toed amphiuma is the largest of the three species. They have a double row of razor-sharp teeth that can deliver a savage bite.

The three-toed amphiuma has three toes on each foot and sports the most contrast between the dorsal and ventral coloration. The three-toed amphiuma is also sexually dimorphic.

Because of their ability to adapt, if the body of water in which they reside dries up, they will burrow into the mud where they can usually survive until the next rain.