At least 22 pilot whales (search) beached themselves on the coast early Saturday, and at least 17 of them died, officials said.

The whales were stranded along a five-mile stretch of land near Oregon Inlet in the northern Outer Banks, said Laura Engleby, spokeswoman for the National Oceanic and Atmospheric Administration.

"We suspect there are more than 30" stranded whales, she said. "The sea conditions have been fluctuating, making it difficult to account for all of them."

It is not uncommon for pilot whales to beach themselves, but scientists do not know why. The pilot whale is a protected species but not endangered.

NOAA's National Marine Fisheries Service was coordinating a recovery effort that involved biologists, Coast Guard crews and the National Park Service.

If biologists determine any of the whales are likely to survive, the Coast Guard will help move them back out to sea, said Petty Officer Donnie Brzuska.

Brzuska said mass strandings of pilot whales are not unusual in Florida and New England, but the stranding on the North Carolina coast was unusual.

Adult pilot whales can reach 20 feet long and weigh up to three tons.