The U.S. Fish and Wildlife Service is conducting an assessment of the eastern hellbender — one of two subspecies — to determine if it should be added to the federal endangered species list. The other subspecies, the Ozark hellbender, found only in Missouri and Arkansas, was declared endangered in 2011 after a 75 percent decline.

Such a designation could free up federal money to protect their habitat and aid in their recovery.

Hellbenders — the origin of the name isn't known — have been present on this continent for at least 10 million years and are found in hill-county rivers and streams in the area stretching from New York to Missouri to North Carolina.

"There's nothing else like them in North America," said federal biologist Jeromy Applegate, who's leading the eastern hellbender assessment.