In the Pacific, off the Galápagos Islands’ coast, a clever ploy leads to a hearty feast. Sea lions cannot typically catch massive yellowfin tuna—which can swim at speeds of around 40 miles per hour. But a few fishermen recently reported a peculiar hunting behavior among the Galápagos dwellers: Using teamwork, the sea lions have been chasing and trapping the tuna in coves along the archipelago’s ragged coast. Photographer Tui De Roy, a Galápagos resident, recently captured this behavior in a series of striking images. The hunting technique was also recently documented on the BBC’s Blue Planet II natural history series.
“I suspect [cooperative foraging] is a lot more common than we think, and there are many more observations that go unreported,” says Dan Costa, an evolutionary biologist at the University of California, Santa Cruz, who had not heard of the behavior before. “Sea lions are very intelligent animals and the prerequisites for social hunting [are] certainly there.”
According to De Roy, the hunt begins when a few sea lions waddle offshore and into the crisp waters around Fernandina and Isabela islands. Some chase the tuna toward coves on the shoreline; others block the fish’s exit back to the open ocean. Trapped between hungry predators and dry land, a few fraught tuna even jump ashore. And what is a feast without uninvited dinner guests? Sharks, frigate birds, pelicans and hawks swoop in for a bite.
Costa suspects sea lion cooperative hunting behavior is similar to that of wolves. When their prey is small, the wolves hunt on their own, he says. But when it is large and can be shared, they hunt in groups. After all, he notes, “In Spanish sea lions are called lobos marinos, or sea wolves!”
The captions in this slide show are De Roy’s eyewitness descriptions, edited for clarity and brevity.