U.S. Giant Salamanders Slipping Away: Inside the Fight to Save the Hellbender

Two-foot-long amphibian declining due to unhealthy streams, disease.

A scientist displays a hellbender in Pennsylvania's Casselman River in an undated photo.

Snot otters. Lasagna lizards. Allegheny alligators. With nicknames like these, you'd think the actual animal, a salamander more commonly known as a hellbender, would be a natural poster child for endangered wildlife.

Instead, hellbenders live quiet lives tucked away under large rocks in the mountain streams of eastern North America, from Arkansas to New York. Ranging in color from mottled olive-gray to chocolate brown with rust-colored splotches, the nocturnal amphibians can easily be mistaken for rocks, if they're seen at all.

But that rarity is what concerns researchers. There are two varieties or subspecies of hellbenders—the Ozark hellbender (Cryptobranchus alleganiensis bishop) and the eastern hellbender (Cryptobranchus alleganiensis alleganiensis)—and both have been quietly slipping away since about the 1980s.

The U.S. government currently considers the eastern hellbender a species of concern, while the Ozark subspecies was federally listed as endangered in 2011. The International Union for Conservation of Nature's Red List of Threatened Species classifies the hellbender as near threatened, although their total number is unknown. (See "'Snot Otter' Sperm to Save Giant Salamander?")

In New York State, researchers began to see small declines in their eastern hellbender population starting in the 1980s, said Ken Roblee, senior wildlife biologist with the New York Department of Environmental Conservation.

But it wasn't until a 2005 survey that scientists saw a 40 percent reduction in the number of adults at monitoring sites, perhaps due to predation or disease—researchers are still trying to figure out the causes. "That got us really concerned," Roblee said.

Declining populations have prompted conservation efforts in New York, as well as in states across the hellbender range, including Ohio and Missouri.

These programs aim to study the biology of North America's largest salamander—which can reach a length of 2 feet (0.6 meter)—as well as to try and reintroduce the animals to the wild.

Murky Future

Salamanders are vulnerable for a few reasons. First, "they are really closely tied to their environment," said Kim Terrell, a conservation biologist with the Smithsonian's National Zoo in Washington, D.C., who studies hellbender immune systems.