Endangered Salamanders That Can Grow to Nearly 3 Feet Released Into Tennessee Streams

In a satisfying conclusion to a conservation effort that began more than half a decade ago, wildlife experts in Tennessee have successfully released 29 eastern hellbenders into local streams.

Without a doubt one of the most colorfully named amphibians in the United States, hellbenders are massive salamanders that can weigh as much as five pounds; their size and slimy texture has also earned them the moniker "snot otter," according to the National Wildlife Federation (NWF).

One of two known subspecies of hellbender, the eastern hellbender inhabits natural water sources in Appalachia as well as Ohio, Missouri, Illinois, Kentucky, and Indiana, the NWF stated. Despite their alarming appearance, they face a host of threats to their continued survival, including but not limited to channeling, damming, and pollution, according to the Nashville Zoo. In Tennessee, hellbenders were once abundant but are now so few and far between that they are considered an endangered species.

In response to hellbender population decline, the Nashville Zoo initiated a hellbender headstart program. Staff collected dozens of hellbender eggs from waterways in central Tennessee in 2015 and raised the resulting hatchlings to young adulthood over the next six years, according to a July 16 blog post by the zoo.

Starting in June, representatives for the zoo as well as the Tennessee Wildlife Resources Agency and Tennessee State University released some of the captive hellbenders into those same waterways in the hopes the animals would be able to repopulate the region naturally. Hellbenders reach sexual maturity between six and eight years of age and can produce between 100 and 500 eggs at a time, according to the NWF. In addition, they have been known to survive for decades.

Donning goggles and snorkeling gear, the team identified submerged nooks and crannies the animals were likely to find appealing before acclimating them to the water à la pet fish, according to a July 16 Facebook video by the zoo. Between June and July, they returned a total of 29 hellbenders to the wild.

But they have dozens more waiting in the wings.

"We still have about 140 hellbenders in our Native Aquatic Conservation Center and plan to release them over the next few years as they grow up. We also plan to collect more eggs for the headstart program and further develop our breeding program," the zoo stated in the blog post.

Prior to their release, the hellbenders were fitted with microchips to help the scientists monitor their location for the remainder of their potentially very long lives, according to the video.

Two young hellbenders photographed in 2014.
Between June and July of this year, Tennessee conservationists released 29 zoo-raised hellbenders into local waters. Two young hellbenders photographed at Marion Correctional Institution in Marion, Ohio, on Dec. 3, 2014. Duane Prokop/Getty Images