Eastern Hellbender

Eastern Hellbender​ (Cryptobranchus alleganiensis​)

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Hellbenders were once widespread in Kentucky streams but are now in steep decline. KDFWR conducts surveys to better understand where the species still exists, though recent surveys suggest they have disappeared from many of the streams in their historic range. Hellbenders can live over 30 years in the wild, and in populations where adults can still be found, young hellbenders are not being found to replace the aging adults. KDFWR has been working on hellbender restoration projects since 2019 to help conserve this imperiled species.

Behavior, Habitat and Conservation Status

The eastern hellbender is North America’s largest salamander. Adults typically range up to 24” long, but some can reach 29” in length. Hellbenders spend most of their time in their self-excavated dens, but venture out at night to forage for food. Despite their large size and somewhat fearsome looks, they are not aggressive or poisonous. They primarily feed on crayfish, snails, small fish, tadpoles, insects, and worms.

Because they breathe through their skin, hellbenders are extremely sensitive to reduced water quality and flow, sedimentation, and other degraded habitat conditions. Dam construction, sand and gravel mining, water pollution, fungal and bacterial diseases, and illegal collection for the pet trade appear to be contributing factors to their decline.​

 ​Biologists are surveying historic hellbender sites to gain a better understanding of current population numbers in Kentucky.​

 

In December 2024, the U.S. Fish and Wildlife Service proposed that the hellbender be listed as a federally endangered species throughout its range. KDFWR is highly interested in all sightings of this rare species. If you see one, please e-mail or text Courtney Hayes (Courtney.hayes@ky.gov, 502.545.1440) with the stream name, exact location, and a photograph of the animal if possible.

Mudpuppy vs. Hellbender - Don't be fooled, they are very similar!

The following traits are key differences between the two similar salamander species. 

 

Figure 1:  The illustration shows a Mudpuppy (left) and a Hellbender (right). Look at the following traits to compare the two different salamander species:

1. ​​External Gills. Mudpuppys have them; Hellbenders do not.
2. Look for skin folds on the side of the salamander. Mudpuppies will look smooth without prominent folds, in contrast to Hellbenders, which have distinct, loose folds of skin on their sides. 
3. Number of toes on the hind (back) feet. Mudpuppies have 4 toes, and Hellbenders have 5 toes.
4. Sizes will be different. Mudpuppies average between 8 and 13 inches in length, compared to the larger Hellbender at 12 to 29 inches in length. 

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Kentucky's Hellbender Program ​

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Statewide Surveys

Statewide distribution of the hellbender salamander remains unclear. Further live trapping and snorkeling survey efforts are needed to locate subadult and adult animals. We are currently surveying known historic sites in the Licking, Green, and Upper Cumberland watersheds and will investigate additional locations with suitable habitat. While working on surveys, we occasionally collect eggs to hatch in captivity, helping to improve the species' survival rate. 

Hellbender Huts

Thirty hellbender nest boxes (‘hellbender huts’) are currently in place within suitable habitat throughout the hellbender’s historical range in Kentucky. These shelters are surveyed periodically to document hellbender use and are checked for regular cleaning and maintenance.

Egg Collection

Hellbenders reach breading age much later than most salamander species--typically 7 to 8 years old. Each fall, adult male hellbenders wait in their dens for females to come and lay eggs--typically, one female lays strands of 100-500 eggs, and multiple females can lay eggs in one den. The male externally fertilizes the eggs and drives off the female. The male will fiercely defend the eggs until they hatch in 4-6 weeks. In the wild, less than 1% of hellbenders survive from egg to adulthood. In captivity, the survival rate can be up to 100%! KDFWR, with the help of our partners at Purdue University, collects and captures some hellbender nests from egg to sub-adulthood to help increase the survival rate for the only known breeding population in Kentucky. 

Captive Rearing

KDFWR’s Center for Mollusk Conservation currently has over 100 subadult hellbenders collected as eggs from a wild nest in Kentucky. KDFWR releases hellbenders using a soft-release method that allows the young hellbenders a few days to acclimate to the exact water conditions in the stream without the threat of predators. In Indiana, this method has been shown to increase the survival rate of reintroduced young to 74%. When large enough, these animals will be tagged and reintroduced into the Licking River watershed. With the help of our partners, we are hopeful to raise additional broods from the Green and Upper Cumberland watersheds.