Bronx, NY – Sept. 1, 2021 The Wildlife Conservation Society’s (WCS’s) Bronx Zoo is working with partners on a multi-year program to save the eastern hellbender, an aquatic amphibian species and one of the world’s largest salamanders. As part of this conservation effort, 124 eastern hellbenders raised at the Bronx Zoo were released into streams in the Upper Susquehanna River Watershed on Saturday, August 28.

For this story, the headlines write themselves – Raising Hell(benders); Head-start to Hell(benders); Hell-Bent on Hellbenders – there are almost as many pithy headline opportunities as there are nicknames for this species of giant salamander. Eastern hellbenders are also known as devil dogs, Allegheny alligators, snot otters, and old lasagna sides.  Native to New York State and much of the northeastern United States, they are a species of giant salamander that can measure nearly two feet in length as adults. Only two larger salamander species are known – the Japanese giant salamander and the Chinese hellbender – both can grow up to six feet long.

New York State lists the eastern hellbender as a species of Special Concern. Populations are declining due to several factors including disease, pollution, and habitat destruction. The Bronx Zoo is working with partners from Lycoming College in Williamsport, PA; SUNY College of Environmental Science and Forestry in Syracuse, NY; and The Wetland Trust based in Burdette, NY to increase the number of hellbenders in the Upper Susquehanna River Watershed.

In October 2017, the 124 hellbender eggs were collected from various streams in the watershed and brought to the Bronx Zoo. There they hatched, and were raised and cared for in the zoo’s Amphibian Propagation Center until they matured to a size that would minimize risk of predation in the wild. This “head start” conservation program gives the animals an opportunity to grow beyond their most vulnerable life stage and offers an increased chance of survival.  The hellbenders were released in the same streams in which the eggs were collected.

“Young hellbenders are vulnerable to predation by fish and other wildlife that share their habitat,” said Don Boyer, Curator of Herpetology at the Bronx Zoo. “By raising them at the zoo they are able to grow to a size that greatly increases their survival rates. In turn, they are more likely to reach maturity and propagate naturally in the wild.”

During their time at the Bronx Zoo, the zoo’s herpetology department staff oversaw the husbandry and management of the species to ensure their health and development. The off-exhibit Amphibian Propagation Center at the Bronx Zoo is a facility with a custom built water purification system that keeps the water chemistry at optimal conditions for the species. This facility and the zoo’s animal care protocols ensure that no novel pathogens are introduced to the watershed when the hellbenders are released.

On August 10, the hellbenders were transported from the Bronx Zoo to the Amphibian Conservation Laboratory in New Berlin, NY for a short lay-over before they were reintroduced to the Upper Susquehanna Watershed. Before being returned to their streams, each animal was tagged under the skin with a tiny microchip that can be used to identify individuals during future surveys and health assessments. They were successfully reintroduced to the watershed on Saturday, August 28.

“The collaboration between Lycoming College, SUNY-ESF and the Bronx Zoo has made significant headway in our effort to restore the Eastern Hellbender to a historic hellbender stream in the Upper Susquehanna River Watershed,” said Peter Petokas, Ph.D., Research Associate, Dept. of Biology and Clean Water Institute, Lycoming College. “Our partnership has enabled the collection of fertile hellbender eggs, long-term rearing of hellbenders for release, restoration and enhancement of hellbender habitat, and regular electronic monitoring of released head-started hellbenders since its inception. As we progress toward our goal of a restored, self-sustaining Eastern hellbender population, we continue our collaboration with partners and community volunteers to ensure that the head-starts attain significant growth and a robust, healthy physical condition.”

The zoo expects the program will continue with a new group of hellbender eggs in the fall.  Previous group of Bronx Zoo-raised hellbenders were released in 2013 and 2017.

Hellbenders are an indicator species. Their presence in a river system can be a sign that the ecosystem is healthy and largely free of pollutants. They absorb oxygen from the water through their skin, which has folds and wrinkles along the sides that increases its surface area and is an adaptation to this unusual “breathing” process.

Hellbenders are usually found in rocky, swift-flowing streams. They hide under large rocks, have flattened heads and bodies, small eyes, and slimy, wrinkly skin. They are typically a brown or reddish-brown color with a pale underbelly. A narrow edge along the dorsal surface of their tails helps propel them through water.

In 2017 the Bronx Zoo opened a specialized exhibit in the World of Reptiles building to showcase these rare and elusive salamanders and tell the story of this important conservation program. The exhibit is a recreation of the river ecosystem where hellbenders live in the wild.