Restoring North America’s largest salamander

Snot otter, lasagna lizard, devil dog—whichever nickname you prefer, the hellbender certainly has a unique charisma. Averaging more than a foot in length and recorded at up to 29 inches, eastern hellbenders are the largest salamanders in North America. Their dark brown skin fits loosely along their bodies, creating folds that adults use to get oxygen. Hellbenders are fully aquatic and breathe entirely through their skin.

“A hellbender is a strictly North American salamander, found only in the eastern part of the United States,” explains Peter Petokas, a research associate at Lycoming College in Williamsport, Pennsylvania, who has spent the last 13 years working with hellbenders.

Though these stocky critters are still found in streams or rivers throughout parts of the Chesapeake region, you’re unlikely to spot one along your walk. Hellbenders are nocturnal, spending most of the daytime hours in burrows underneath large rocks. Even while hunting, they tend to sit just at the edge of their rocks and wait for prey, usually crayfish, to come by.

“It just blew me away that we had a salamander this large right in our backyard. You know, they’re so secretive, you may use a stream your entire life and never see one,” says Michelle Herman. Herman worked with Petokas as an undergraduate at Lycoming and continues to work with hellbenders as a graduate student in conservation biology at the State University of New York (SUNY) College of Environmental Science and Forestry in Syracuse, New York.

Adult hellbenders get oxygen through their loose, folded skin. Hellbenders also have a single pair of hidden gill slits, explaining the scientific name Cryptobranchus: it's Greek for hidden gills. (Photo by Will Parson/Chesapeake Bay Program)

The decline of the hellbender

These secretive creatures are difficult to find for another reason: population loss. Over the past 30 years, the species has declined due in large part to water pollution, habitat degradation and disease.

Hellbenders breathe through their skin, making high-quality streams incredibly important to their survival. They prefer cold, clear, fast-moving waters, which have higher oxygen levels, and a rocky stream bottom for shelter. Unfortunately, this kind of habitat has become harder to come by.

The Susquehanna River watershed has a long history of forest removal, motivated by timber industries, promoting agriculture and increasing development. This led to increased erosion and allowed sediment to wash into waterways, creating cloudy waters and smothering the river bottom. A lack of stream-side trees also means less shady waterways, which leads to warmer water. Dam construction can slow the flow of water, which makes the water warmer and less oxygenated, and block hellbender migration, which is important for gene flow and recolonization. In addition, people have removed large rocks that provide shelter to hellbenders to make room for recreational activities like kayaking or rafting.

Petokas notes that the problem has been somewhat overlooked because of the hellbender’s reclusive nature. “Because it’s such a secretive animal living under these really large rocks, when it disappears, people don’t recognize that it is no longer present.”

Disease is also a potential factor in the hellbender decline. “One of the things that we’ve learned about the hellbender is that it currently harbors a disease called the chytrid fungus,” says Petokas. “Up to 40 percent of the hellbenders in the wild are actually infected with the fungus.”

This fungus is one of the causes attributed to the decline of amphibians globally, as it interferes with the ability to get oxygen and water through the skin. However, it’s still unclear exactly how the fungus affects hellbenders and the role that it might have played in their population decline.

Raising hellbenders

Hellbenders can live for 20 to 30 years, but many don’t make it to adulthood. They are most vulnerable in their egg and larvae stages, when they are potential prey for smallmouth bass, rainbow trout, brown trout and even adult hellbenders. One strategy researchers are implementing is to raise juveniles in captivity to try to get them past this vulnerable stage and increase their chances of survival in the wild as adults.

“We have collected some eggs from the wild, from both New York and Pennsylvania in the Susquehanna watershed, and we’ve taken those eggs to the Bronx Zoo for rearing for several years to have them reach an age at which they are large enough to avoid predation when they’re released back into the wild,” explains Petokas. “Our plan is to release these animals at three and a half years of age back to the wild, into habitat that has also been enhanced and restored.”

Herman also says that the program provides a chance to research different rearing approaches, to see whether different strategies increase their ability to survive later on. “We’re going to be subjecting these animals to various water treatments and different diets, and we want to monitor their growth and health throughout this process.” She will follow up with the young hellbenders, which were released this August, to determine whether certain groups do better in the wild.

Going forward, rearing programs will need to be coupled with habitat restoration efforts to give hellbender populations their best chance, says Herman.

“I think to ensure that hellbenders have a bright future, we would want to continue with some best farming practices.”

Best farming practices refers to conservation strategies like planting forest buffers, which can reduce sedimentation and other pollution, as well as keep the stream shady and cool.

Though hellbenders still have a long way to go, Herman is hopeful for their future and is enjoying the opportunity to work with them. “I’ve always loved water, I’ve always loved being outside, so getting to be a biologist and try to restore habitat for animals and aquatic life—it’s just been my dream job,” she says.

“I think we can do this together. I would love to see the day that [researchers] are able to go out and find 20 or 50 animals in an outing.”