Skin ranges from brown to gray to almost black. There may be irregular, light mottling on its back. The belly is lighter in color. The coloration makes the Hellbender very difficult to see against the rocks and debris found along the bottom of streams. A large salamander, 30 - 69 cm (12-27 in) long. Adult males are smaller than females.
A Hellbender reaches sexual maturity in four to seven years. The male defends a territory in the stream throughout the breeding season and evicts other male competitors. Hellbenders breed in early fall, laying 300 - 500 eggs in gelatinous strings under larger rocks or logs in the stream. Fertilization is external. The male usually guards the eggs, which hatch in six weeks. The young lose their external gills when their length reaches 10 - 13 cm (4 - 5 in), but a Hellbender's lungs are not very effective. Breathing is primarily by means of the folded skin on either side of the body. Capillaries in the folds diffuse oxygen into the blood. The Hellbender is completely aquatic and is nocturnal. It eats crayfish, salamanders, snails, aquatic insects, and fish captured by suction. The Hellbender needs ample habitat including large rocks, logs and other debris in large, fast-flowing streams, for shelter. The Hellbender is in the same family as the largest salamanders in the world, two species of salamanders in the genus Andrias which are found in China and Japan and reach lengths of 150 cm (5 ft). Despite its size, the Hellbender is harmless and its bite is not poisonous. It can live for many years in captivity; the record is 29 years.
The Hellbender is found in extreme North Georgia in streams that flow north into the Tennessee River drainage.
The Hellbender is listed in Georgia as Rare and is being considered for Federal listing. It is not abundant anywhere in its range, although in certain streams it may be common. The major threat is habitat destruction. The large, clear, fast-flowing streams in which it lives are particularly vulnerable to degradation through siltation, pollution, and impoundment. These habitats must be protected.
The Mudpuppy is the only other giant salamander found in north Georgia. Adult Mudpuppies have external gills and lack folds along the body.