Eastern Hellbender
- Status
- Critically Endangered
- Endangered
- Least Concern
- This animal is currently Near Threatened
- Vulnerable
Eastern Hellbender
Cryptobranchus alleganiensis
Named Pennsylvania’s State Amphibian in 2019, the Eastern Hellbender is a large, aquatic salamander found in cool, clear streams across 15 states in North America. Growing to over two feet long and weighing more than four pounds, they are North America’s largest salamander and the third largest salamander in the world after the Chinese and Japanese giant salamanders. Hellbenders breathe entirely through their skin, which has numerous fleshy folds along the sides of their bodies to increase oxygen absorption; they do have lungs, but they are used for buoyancy instead of breathing.
Hellbenders are classified as Near Threatened by the International Union for Conservation of Nature (IUCN). Many different anthropogenic sources have helped to create this decline, including the siltation and sedimentation, blocking of dispersal/migration routes, and destruction of riverine habitats created by dams and other development, as well as pollution, disease, and overharvesting for commercial and scientific purposes. Members of the Pennsylvania State Senate voted to approve the Eastern Hellbender as the official state amphibian in an effort to raise awareness about its endangered status.
When breeding, males excavate a large nest chamber beneath a rock in preparation. Pregnant females are either attracted to or corralled into the nest sites by the males. Egg laying typically happens in the late summer or early fall, depending on the elevation. Females deposit two long strings of 200 to 400 eggs in a softball-sized, yellowish mass onto the nest bed. Males fertilize the eggs externally as the female deposits them. Males then drive out the females and stay in the nest cavity to brood and safeguard the eggs until they hatch 68 to 75 days later. At hatching, the larvae are about 1–1.25 inches (25 to 30 millimeters) in length. It is thought that the larvae suffer high mortality during the first years of life, often falling prey to fish and other predators. Males and females become sexually mature in about 5 to 7 years.
What are they like?
Physical Description: With a flattened head and body, four short, stout legs, a long rudder-like tail, and very small, beady eyes, Eastern Hellbenders are well adapted to their swift, flowing stream habitats. They vary in color from grayish to olive brown and occasionally, entirely black. They range from 3.3–5.5 pounds in weight and 12–29 inches in length.
Life Span: In the wild, Hellbenders can live 30-35 years. In zoos, they typically live 30+ years.
Diet: In the wild, Hellbenders eat insects, tadpoles, crayfish, small fish, snakes, and other hellbenders and their eggs. At the Zoo, they eat a diet of insects.
Social Structure: Hellbenders are solitary creatures except for during the breeding season when they have been known to congregate, sometimes during the day, in groups of ten or more individuals.
Habitat: Hellbenders live in freshwater streams with large, flat rocks at the bottom used for shelter and avoiding predators. Free-flowing streams provide more dissolved oxygen and prey, namely freshwater invertebrates. Hellbenders prefer streams with gravel substrates as opposed to mud, allowing larvae more protection.
Where do they live?
The eastern hellbender’s North American range extends from southwestern and south-central New York, west to southern Illinois, and south to extreme northeastern Mississippi and the northern parts of Alabama and Georgia. A separate population occurs in east-central Missouri. In New York, the hellbender is found solely in the Susquehanna and Allegheny River drainages, including their associated tributaries.
North America
Did you know?
- Hellbenders are nocturnal animals, seeking cover by day under large rocks and logs and becoming active at night to hunt.
- Eastern Hellbenders have a wide variety of aliases! Vernacular names for Hellbenders include snot otter, devil dog, mud-devil, mud dog, grampus, and Allegheny alligator.
- Hellbenders have tiny eyes located on the tops of their heads that can detect light but are not very good at forming images. They also have light-sensitive cells located all over their bodies, especially on their tails. This might help them keep their whole bodies hidden under rocks and logs. When hunting, they likely use their keen sense of smell and their lateral line, which detects vibrations in the water.
Pennsylvania's State Amphibian