Eastern hellbender

Physical features

• Hellbenders are large, fully aquatic salamanders that are characterized by flat heads and loose folds of skin located along the lower sides of their bodies.

• Adults average about 12.5 ounces (3/4 of a pound) but can reach 16 ounces (two pounds) and vary in length between 11-29 inches.

• Although hellbenders can swim they prefer to walk along the bottom of the rivers in which they live. Their flattened shape allows them to move especially well along the bottom of fast-moving streams.

• Hellbenders are nocturnal except for some diurnal activity during the breeding season.

• Hellbenders are solitary animals outside of the breeding season and violent conflicts often occur during meetings between two hellbenders. However, recent observations have shown multiple adults cohabitating for periods of time under the same rock.

• Hellbenders suck their prey into their mouths.

• Hellbenders are sexually dimorphic with females being somewhat larger than males.

Diet: Carnivore

• Wild – Crayfish, insects, fish, worms, other salamanders, and even water snakes

• Zoo - Crayfish, fish, worms, rodents

Reproduction

• Adult hellbenders typically only come together to breed. Males stake out territories under large rocks to provide a nesting area to attract females. These rocks are highly sought after by other males and fights often occur over nesting rocks.

• Female hellbenders lay 100-500 eggs which are then fertilized by the male. The eggs hatch 68-84 days after fertilization. Hellbender larvae begin life approximately 1 inch long and have external gills until they reach approximately 2 years of age.

• Hellbender eggs are guarded by their father until they hatch. He will use his tail to fan the eggs to help increase oxygenation.

• The larvae may remain under the cover rock with their father for weeks or months after hatching.

• Hellbenders become sexually mature between 5 and 8 years of age.

• Hellbenders are one of the few salamanders to exhibit external fertilization.

Interpretive Information

• Fish, minks, otters, raccoons, snakes, owls, turtles and humans are some of the main predators of hellbenders. Larger hellbenders may also eat smaller hellbenders.

• Hellbenders are usually solitary animals outside of the breeding season and violent conflicts often occur during meetings between two hellbenders.

• The hellbender is the largest species of amphibian in North America.

• The genus name Cryptobranchus loosely translates to "hidden gills." This is a reference to them having tiny gill slips as adults that are covered by a flap of skin.

• Hellbenders utilize the increased surface area of the flaps of skin along their sides to absorb more oxygen from their underwater environment.

• Hellbenders have lungs, but their primary function is more for buoyancy than for breathing.

• The closest living relatives of hellbenders are the giant salamanders (genus Andrias) found in China and Japan.

• No one is fully sure why they're called hellbenders, but it is mostly believed to be based on their unusual appearance. One investigator has proposed that it may be based on the "Americanization" of the German word for alligator, which is what hellbenders were often called in the late 1700s and early 1800s.

• They have many colorful colloquial names, including devil dog, lasagna lizard, grampus, and snot otter.

Updated July 2024