Whale watchers in California's Monterey Bay got a double dose of action this week when a pod of orcas came inland to feast on the carcass of a gray whale. 

The footage of Monterey's mammal-hunting ("transient" or "Bigg's") orcas foraging in this way is thought to be the first of its kind – and it holds clues about the hierarchy within the pods.


It's tough to say with certainty whether or not this particular pod killed the gray whale, but the group has been enjoying its fill of the spoils.

"Over 35 hours and [they were] still feeding as we left!" the team at Monterey Bay Whale Watch (MBWW), who captured the event with a drone, said after the initial sighting. "This is a perspective we could not get from our boat. It's very useful for our behavioural research to learn more about how the orcas share their prey and what individuals are involved."

"Meal sharing" has also been observed in mammal-hunting killer whales off the coast of Norway, so it will be interesting to see how the group dynamics differ in the two locations. 

It might seem odd that a top predator would hand over its hard-earned meal to fellow pod members, but sharing ensures that all of these pack hunters stay healthy, giving the pod the best chance of taking down prey in the future. 

You might notice that two adult whales barge towards the feasting orcas in the video. MBWW co-owner and marine biologist Nancy Black explains that – contrary to some suggestions online – the animals are actually a pair of humpbacks. 

"[They] approached the orcas and began trumpet blowing, rolling, and became surface active among the killer whales," the team said.

It's not that unusual for humpbacks to interfere in situations like this, but the exact reason behind the behaviour is still up for debate. Some suggest this is an example of interspecies altruism, with the humpbacks coming to the aid of their not-so-close kin. Others suspect it's merely a move to protect their own. 

While Bigg's orcas tend to eat smaller prey like seals and dolphins, it's possible that we'll see more interactions like this one during the coming months: as winter approaches in the Southern Hemisphere, filter feeders such as gray and humpback whales are migrating north to warmer waters. 



Top header image: Gilad Rom/Flickr