Whale watchers off the coast of Orange County recently witnessed firsthand the hunting prowess of killer whales when a pod, believed to belong to a population from the Eastern Tropical Pacific that is rarely seen in waters around California, dispatched a dolphin calf after a high-speed chase. Photographer Matt Larmand witnessed the hunt from a Dana Wharf Whale Watching boat and used a drone to capture amazing aerial footage of the action.

The orcas were initially spotted cruising up the coast towards Orange County, but things heated up when they narrowed in on a pod of common dolphins. "It was surprising to me with what persistence they chased this dolphin pod,” Newport Coastal Adventure owner Ryan Lawler told The Mercury News. "They chased it for two miles at a constant pace – like wolves chasing down their prey, trying to tire their prey out."

Killer whales are among the world's fastest-moving marine mammals, capable of clocking speeds over 30 miles (48 kilometres) per hour (an impressive feat when you consider that they can weigh up to 11 tons!). The black-and-white predators are armed with a mouth full of large, interlocking teeth and are highly intelligent and social – which makes them particularly efficient killers.

Hunting tactics are typically defined by what's on the menu: schools of fish are snared in a net of bubbles from below, while sharks are likely rammed and then their bodies torn open just below the pectoral fin so the orcas can hoover up their nutrient-rich livers. But when it comes to nippy and agile common dolphins, the hunt often sees killer whales teaming up in a coordinated attack and pursuing their quarry at high speed.

"They went after that [dolphin] baby. I guess that was an easier target," Larmand recalls. "They’d come from different directions, they were corralling it and getting it to go in the direction they wanted it to go. They knew exactly what they were doing and how to do it. It was crazy to watch."

Whale-watching guides and marine researchers identified the orcas as belonging to a group usually found in the Eastern Tropical Pacific (ETP) and – according to Alisa Schulman-Janiger, co-founder of the California Killer Whale Project – it's unusual to encounter them at this time of the year. ETPs usually hang out in waters off Mexico or Costa Rica and turn up occasionally in California from November through January when the water is a bit warmer, she explains.

Schulman-Janiger will be analysing photos in an attempt to identify the individuals, but she suspects that this group is not the same one that turned up in town late last year. Not much is known about ETP orcas, but marine mammals do seem to make up, at least, part of their diet. 

Orca Launches Dolphin 2015 10 26

Top header image: timnutt, Flickr