What Are Hellbenders?

An eastern hellbender held by a researcher.
An eastern hellbender held by a researcher. USFWS / Jill Utrup

The hellbender is not a beast haunting Harry Potter’s world, but a stream salamander that probably got the unfair name from its looks and size. Adults can exceed 24 inches in length and weigh 5 pounds. The species boasts a wide, flat head and body, tiny beady eyes, unusually wrinkly skin, and a large swimming tail. Despite its appearance, the hellbender is harmless to humans. Conversely, we have found many ways to damage its habitat and threaten its populations.

Ecology

Hellbenders are aquatic salamanders which live in the fast-moving sections of shallow rivers. The species range is centered on the Appalachian Mountains, extending west to Missouri with a north-south spread from New York to northern Alabama. Hellbenders require rivers with well-oxygenated, clean water and large rocks under which they take cover. Crayfish constitute around 80% of the food items captured by hellbenders, and the rest is mostly fish with the occasional snail and aquatic insect.

It takes 5 to 7 years for hellbenders to be sexually mature, and they probably can live to 30 years. Interestingly, it is the males that guard the eggs in a burrow tucked under a large rock. The eggs will hatch in a month and a half to two months.

Juvenile hellbenders have gills, but when they become adults they absorb oxygen through their skin. Despite the salamander's large size, this method of respiration is sufficient due to the high oxygen concentration in the water and the large folds of skin it possesses - it also makes them very vulnerable to water pollution.

That skin can produce slimy secretions when a hellbender is handled, giving it the unfortunate nickname of snot-otter in some locales.

Taxonomic authorities generally recognize two subspecies, the eastern hellbender, and the Ozark hellbender. The latter is found in a few rivers in Arkansas and Missouri.

Threats to Hellbenders

Given how striking these animals are, their secretive nature and a long-held disdain for amphibians mean that there have been surprisingly limited studies on their ecology and conservation needs. A decline in hellbender populations over much of their range is readily apparent, with numbers down significantly almost everywhere. The causes are mostly related to its need for clean, cool, well-oxygenated water. Reasons for the degradation of river habitat include:

  • Hydroelectric dams turn fast flowing rivers into still reservoirs, which do not have the qualities needed by hellbenders.
  • Road construction, logging, mining, and any other activity that kicks sediment into streams, smothering gravel beds and making them unsuitable for the hellbenders and their prey items. Any activity that removes vegetation from the stream sides will result in a reduction in shade and warmer water. As water temperature increases its oxygen holding capacity decreases, pushing hellbenders out of those areas.
  • Acid mine drainage will change the pH of the streams, killing eggs, larvae, and adults.
  • Running livestock next to streams contributes nutrient pollution, which ultimately decreases oxygen levels in the water.
  • Intentional killing is still common among anglers, who wrongly believe that hellbenders are dangerous, or that they compete with them for fish.
  • Illegal collection has been a problem in some parts of their range.
  • The Ozark hellbender seems to be particularly affected by heavy recreational use in the rivers it occupies. Hellbenders tend to respond poorly to large numbers of anglers, boaters, and other types of intense human activity.

In a worrisome development, the chytrid fungus threatening frogs worldwide has recently been found on hellbenders. It is currently unknown how much of a threat the fungus is to hellbender populations.

The St. Louis Zoo has a conservation program centered on the Ozark hellbender, with captive breeding activities.

Federal Government Protection?

Since 2011 the Ozark Hellbender has been listed as endangered under the United States Endangered Species Act, providing it with much-needed protection.

Petition to list the eastern subspecies have been filed, but for now , it has no federal protection. Several states including Ohio, Illinois, and Indiana have hellbenders on their protected species list.

Sources

Center for Biological Diversity. Hellbender.

IUCN Red List of Threatened Species. Cryptobranchus alleganiensis.

USFWS. Eastern Hellbender Status Assessment.