Eastern Hellbender

Cryptobranchus alleganiensis alleganiensis

Eastern Hellbender: North America's Giant Skin-Breathing Salamander

The eastern hellbender is North America's largest amphibian, a flat, wrinkly giant salamander of clear, fast streams in the eastern and central United States. It breathes mostly through its skin, hunts crayfish at night, and the males guard the eggs under big rocks.

Habitat

Cool, clear, fast-flowing streams and rivers with large flat rocks

Size

Adults 30-74 cm long, up to about 2.2 kg

Diet

Mostly crayfish, plus small fish, snails, worms and aquatic insects

Range

15 eastern and central US states, from New York to Georgia and Missouri

Conservation

Vulnerable (IUCN); Missouri population federally Endangered

Lifespan

Up to about 25-30 years in the wild

Habitat & range

Eastern hellbenders live in cool, permanent streams and rivers in 15 states of the eastern and central United States, from New York and Pennsylvania south to Georgia, Alabama and Mississippi and west to Missouri (US Fish & Wildlife Service; Federal Register 2024). They need swift, well-oxygenated, unpolluted water with riffles and plenty of large flat rocks or logs for cover and nesting (Smithsonian's National Zoo). They are homebodies. Left undisturbed, a hellbender may spend almost its whole life in a stretch of river about 200 feet (61 m) long (Smithsonian's National Zoo). Missouri is the only place where both the eastern hellbender and its cousin, the Ozark hellbender, are found (Missouri Department of Conservation).

How to recognise it

A hellbender has a flattened head and body, four short, stout legs, a long rudder-like tail and very small, beady eyes without eyelids (Smithsonian's National Zoo). It is greyish to olive brown, sometimes all black, usually with dark mottling. Adults are 30-74 cm long and weigh up to about 2.2 kg, making it North America's largest amphibian and the third-largest salamander after its Asian cousins, the Chinese and Japanese giant salamanders (Smithsonian's National Zoo). The loose, wrinkled skin folds along its sides earned it the nickname 'lasagna sides', and its slime gave it 'snot otter' (Missouri Department of Conservation).

Diet & hunting

Adult hellbenders mostly eat crayfish, plus small fish and the occasional snail, worm or aquatic insect, and they will scavenge (Missouri Department of Conservation); the Saint Louis Zoo puts crayfish at about 90% of the diet (Saint Louis Zoo). They hunt at night, finding prey by smell and touch (Saint Louis Zoo). To crunch through crayfish shells they have two rows of small teeth in the upper jaw and one row in the lower (Missouri Department of Conservation).

Behavior & adaptations

Hellbenders breathe mainly through their skin, absorbing up to 95% of their oxygen through it, mostly via the wrinkled side folds. Their lungs are largely non-functional for breathing and mostly help with buoyancy (Smithsonian's National Zoo). That is why they need cold, clean, fast water. Males are rare amphibian dads. Each digs a nest chamber under a rock; a female lays two strings of 200-400 eggs, which he fertilises and then guards alone for 68-75 days until they hatch (Smithsonian's National Zoo). He fans the eggs by rocking his body, though hungry fathers sometimes eat some of their own eggs (Smithsonian's National Zoo).

Conservation

The hellbender is listed as Vulnerable by the IUCN, with an estimated 30-50% decline over about 30 years due to disease and habitat loss (IUCN Red List). Of 626 known historical eastern hellbender populations, 41% are believed to be gone and another 36% are declining, mainly because of sediment, poor water quality, habitat destruction and disease (US Fish & Wildlife Service). Zoos help by head-starting young hellbenders, raising larvae until they are big enough to escape most predators and releasing them into occupied streams, and several states use artificial nest boxes (US Fish & Wildlife Service). If you find one, leave it and its rock where they are: hellbenders depend on large flat rocks for shelter (US Fish & Wildlife Service).

Fun facts about Eastern Hellbender

• A hellbender can absorb up to 95% of its oxygen through its skin (Smithsonian's National Zoo).
• Nicknames include snot otter, devil dog, grampus and lasagna sides (Missouri Department of Conservation).
• Male hellbenders guard their eggs for 68-75 days, but may eat some if hungry (Smithsonian's National Zoo).
• An undisturbed hellbender may spend nearly its whole life in about 200 feet of river (Smithsonian's National Zoo).
• Pennsylvania named the eastern hellbender its state amphibian in 2019 (Philadelphia Zoo).

Eastern Hellbender vs Japanese Giant Salamander

The Japanese giant salamander wins on size; it is about ten times heavier.

These two are cousins in the giant salamander family, but they live an ocean apart: the hellbender in streams of the eastern United States, the Japanese giant salamander in the rivers of western Japan. In a made-up showdown, size decides it. A big hellbender is about 74 cm and 2.2 kg (Smithsonian's National Zoo), while the Japanese giant can reach about 1.5 m and 25 kg (Animal Diversity Web). Both are slow, slimy ambush hunters with wide mouths, so this would be a short wrestle. Our verdict: the Japanese giant salamander wins on sheer bulk.

Read more about Japanese Giant Salamander.

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