Blue whales are off California gorging on shrimp-like krill, in a summertime mission so purposeful that a single mammal can devour up to 8,000 pounds per day. But boys will be boys, as whale-watchers discovered Friday, when they enjoyed a rare and awesome sighting of two male blue whales fighting over a female (see video).

This was the assessment of veteran skipper Dave Anderson, of Capt. Dave’s Dolphin and Whale Safari, which uploaded the video Saturday under the heading “The Real Heavyweight Fight of the World!”

And it appears to be the most plausible explanation for the dramatic, explosive behavior, which occurred off Dana Point, California.

The American Cetacean Society’s Orange County Chapter posted this statement on its Facebook page, with the video: “WHALE FIGHT! A ‘competition pod,’ the kind we normally associate with humpbacks in their mating grounds, was seen yesterday off Dana Point, but with BLUE whales. Incredible, dramatic speed and agility displayed by these huge animals.”

Anderson said he had never witnessed this type of event, and added that he only caught part of the clash on video because he could not be sure where the whales would surface.

The footage shows a rare blue whale breach (at the 20-second mark) and series of violent bursts and fin-slaps, which are not typical during feeding. Blue whales are the planet’s largest creatures; they can measure up to 100 feet and weigh up to 150 tons, so breaching requires an incredible amount of energy.

“At one point one of the whales separated from the other two and everything stopped. We hung back and followed the one whale, and then he caught up to the others and it all started again,” Anderson said. “But it was short-lived. It seemed like he had had enough.”