Transient orcas spotted feeding on grey whale near B.C.

A whale watching tour off the coast of Washington state got a rare and gory treat this weekend when it stumbled upon a group of killer whales feeding on a small grey whale.

The Puget Sound Express tour was south of Whidbey Island on Saturday when the crew spotted the transient orcas circling their prey.

"It only took a couple seconds and I could see some of the intact skin of the grey whale, and I was like, 'wow that's a grey whale,'" naturalist and photographer Bart Rulon told CHEK News.

The group of four killer whales included a matriarch and her three large adult sons, according to the whale-watching company. They could not say definitively whether the orcas had killed the grey or if it was already dead when they began feeding.

"We did see some blood bubbling out," Rulon said.

Members of the crew said they've never seen anything like it.

Transient killer whales specialize in hunting mammals, including seals, porpoises and dolphins, and occasionally feed on the calves or juveniles of larger whale species like greys.

This season has seen an unusually large number of grey whales washing up dead along the shores of western North America. So far, more than 60 have been discovered between California and Alaska.

Dead whales examined by the U.S. National Oceanic and Atmospheric Administration have been found to be malnourished.