Scientists Discover How Killer Whales Learn to Hunt

Feb. 1, 2006 — -- When he first saw a young killer whale swimming with a sea gull in its mouth, Michael Noonan didn't realize the giant sea mammal was demonstrating a mental ability once thought to be exclusively human -- "cultural learning."

In recent years, scientists have documented a number of examples of animals learning how to do something differently by mimicking other members of their species who have figured out a better way. It's called cultural learning or cultural transmission, and it is the literal embodiment of "monkey see, monkey do."

Except as Noonan says, this is a case of "whale see, whale do." But they weren't supposed to do that sort of thing. That was supposed to be our routine, not theirs.

"In general, humans have long pictured themselves as separate from nature, but one of the lessons that we repeatedly learn when we study animal behavior is that animals are much more like us than we ever imagined, and we are much more like them than we had thought," says Noonan, a psychologist at Canisius College in Buffalo, N.Y., and a specialist in animal behavior.

Noonan came across his discovery through a bit of serendipity. He was studying acoustic communications among killer whales, technically known as orcas, at Marineland of Canada in Niagara Falls, Ontario, and he visited the park nearly every day.

"Since I'm there on a daily basis I get to observe whatever the whales are doing while going about my formal data collection processes," he says. "When things happen that are out of the ordinary I usually make a note of it, and that's how I came to discover this."

What he discovered was a 4-year-old male orca swimming around the pool with a sea gull in its mouth. That wasn't a terrible surprise since animals of all sorts fall prey to others when they wander into the wrong territory.

The surprise came when Noonan learned how the whale caught that gull. During feeding time, when lots of gulls are in the area in hopes of snatching a stray fish, a young whale decided to share part of its lunch with the gulls.

"The whale spit fish at the surface of the pool and then sank below and waited," Noonan says. "The gull came down to get the fish, and the whale grabbed it."

Pretty interesting, but what really got Noonan's juices flowing came a few weeks later. Another young whale, the half-brother of the inventor, copied the technique.

"Both whales were pretty good at it," Noonan says. "They caught a sea gull once every 20 days or so."

Still later "one of the adult females started doing it, and then within another year the other adult female started doing it." And not long after that a baby orca was born and started copying mom.

"That was amazing because the baby took fish and spit it at the surface, and it doesn't even eat fish and it doesn't eat gulls. It was very young, and still nursing, so it was clearly just copying its mother."

Still later the ultimate test came. The old male in the pod was the last to get with the program, but eventually he even tried to lure a gull within his reach. It was too old to pull it off, Noonan says, but at least it tried.

"So it spread through the entire community," Noonan adds, and the pattern was the same as observed among some other animals. There is the famous case of wild monkeys in Japan, who were fed sweet potatoes by members of a religious order.

Monks from the order would toss the potatoes onto a beach, and the monkeys would scarf them down, sand and all. But one day a female monkey took her sweet potatoes to a nearby stream, dunked them in the water and washed off the gritty sand. Over the course of several years the others followed, first the youngsters, then the females, and finally the old men of the colony.

Other experimenters, notably researchers at the Yerkes National Primate Research Center of Emory University, have shown that chimps can learn by watching other chimps that have been taught by humans how to use a tool to retrieve food. In time, all the chimps were doing it, so it had become part of their culture, to be passed on to others.

Scientists point out that none of the animals is actually teaching the others how to do something. Instead, animals are learning by simply observing others who have been successful at doing something, usually getting food.

What is different about Noonan's work, however, is it involves something that is rare in the animal world. The orcas in the aquatic park had learned how to set a trap, and that knowledge had been acquired by other members of the pod.

Their culture had expanded, as well as their diet, through a bit of clever innovation that eventually was shared by all.