Blue whales, thought to be the largest animals on earth, have been sighted feeding of the coast of Southern California - a rarity, given that they usually feed far below the water's surface.

The whales, which are blue-gray in color and can be more than 100 feet long, were sighted off the coast of Laguna Niguel, according to ABC Los Angeles station KABC-TV. The station's video shows a whale torpedoing through the water near the surface with its mouth wide open as it gulps down krill, the shrimp-like organisms it feeds on.

"They're so close," Larry Fukuhara of the Cabrillo Marine Aquarium in San Pedro told KABC, adding that they were only three miles off the coast. "A lot of times, what I hear on the East Coast you have to go miles and miles and miles. They're relatively close, which I think is, once again, fabulous and fascinating."

He said the whales usually dwell in deeper, colder waters where their food lives, but the cold water is closer to the surface right now. They could stay near Southern California for another month before migrating elsewhere.

The whales eat about 40 million krill a day during the summer months, which amounts to about 4 tons, according to the American Cetacean Society.