SAVANNAH (AP) — What caught the eye of researchers from the University of Georgia and Gray's Reef National Marine Sanctuary 65 feet under water was a bone encrusted in an ancient shell bed at JY Reef, an area north of Gray's Reef National Marine Sanctuary.

"I thought it was from a mammoth," said Scott Noakes, a research scientist at UGA.

Noakes and his colleagues were studying the structure of the reef, where others had previously found bison teeth and wooly mammoth rib fragments, which was why he was predisposed to think of those prehistoric beasts.

The divers knew the jawbone was old because of its placement in the shells thought to be more than 30,000 years old. The mammoth idea was nixed as more of the bone was uncovered. Its shape pegged it as a whale bone, though they figured it was from a North Atlantic right whale, a highly endangered species that still migrates to the Georgia waters to give birth.

In a series of 30-minute dives over two years, researchers painstakingly removed the bone in sections from its resting spot, first brushing aside sand then chiseling away hard-packed silt and finally cutting through the ancient scallop shells.

"It was like slowly unwrapping a present a few peeks at a time," Noakes said.

Analysis at the Smithsonian National Museum of Natural History in Washington, D.C., identified the nearly five-foot long bone as that of an Atlantic gray whale.

The find was published recently in the journal Palaeontologia Electronica.

Atlantic gray whales, which grew to 50 feet long and were known as "devil fish" for their feistiness, were sought after for their high oil yield. Whalers hunted them to extinction in the 1700s, researchers believe.

This particular animal was not killed by humans, however. Carbon dating puts the whale bone — which is technically a "subfossil" because it hadn't completely fossilized — at 36,000 years old. Humans lived then, but they weren't whaling yet, said Gray's Reef Deputy Superintendent and Research Coordinator Greg McFall, who helped to excavate the find.

The area where it was found, about 20 miles off the coast of St. Catherines Island, was likely shallow water or beach when the whale died.

Casts made of the jawbone and painted to replicate the fossil will go to the Smithsonian, the UGA campus in Athens, the Georgia Aquarium and the UGA Marine Extension Aquarium on Skidaway Island.

Noakes hopes the story of the gray whale will bring attention to the plight of the north Atlantic right whale, which has only about 400 individuals remaining and is in danger of following the grays into extinction.

"Yes, it can happen," he said.