Sperm whales in the 19th century taught each other how to attack whalers by ramming the boats with their head, scientists have found.
Hal Whitehead, research professor in the Department of Biology at Dalhousie University, made the discovery while delving into log books kept by whalers in the early 1800s.
Whaling, which refers to the hunting and killing of whales, was a thriving industry in 19th-century America. Ships would set sail from ports in New England and travel across the globe, capturing and killing the marine mammals to make whale oil.
The oil, derived from a whale's blubber, was used for lighting and lubricating purposes. Even a whale's bones would be used to make a wide variety of products such as children's toys and corsets.
Sailors would take down whales with harpoons attached to a heavy rope. Dead whales would then be tied and stowed to the ship. Ashore, the whale's skin and blubber would be peeled off in long strips and boiled down to make the oil.
However, a particular group of whalers sailing in the North Pacific in the 1820s began having trouble with sperm whales, according to Whitehead, as their harpoons were not taking down the whales as effectively. This piqued Whitehead's interest.
The logbooks included anecdotes and descriptions of how the whales began to evade the harpoons within a few years of the sailors being there.
Whitehead told Newsweek: "What it strongly suggested was that the whales changed their behavior very quickly, within two or three years of meeting whalers. They were behaving very differently."
To protect themselves against predators, such as killer whales, sperm whales usually cluster together in a large group, forming a tight circle of defense. But this didn't work against man, as it formed a perfect target. And so they changed their strategy, Whitehead said.
Within just a couple years, when attacked by the sailors, the whales began swimming fast upwind and doing deep dives out of range. Whitehead found that they even began attacking the whalers directly in their boats by ramming them with their huge heads. There was only one explanation for this: the whales were talking to each other and learning from each other, according to Whitehead.
"When the whales would do a deep dive and come up somewhere very different, it would really throw the whalers off. Because the whalers would wait for the whale to come back up to the surface but it would pop up miles away. And that was no good to them, the whale had escaped," Whitehead said.
"They have great big jaws and teeth, and the whale boats were floaty little things so they could smash them up and sometimes they did. The way they defended themselves is very different to how they protected themselves against other predators."
Whitehead said even one encounter with the whalers gave them enough information to pass it on rapidly across large areas of the North Pacific.
"They depend a lot on the information they learn from each other, and what they learn changes their behavior, and that's whale culture. It's the same as how we learn things from parents or teachers," Whitehead said.
Sperm whales communicate to each other through "clicking" sounds and patterns, Whitehead said.
"Those clicks are the loudest sound made by any animal. The sperm whales can hear each other and they can probably identify each other from their sounds too. In that sense, they are aware of where everybody is and what they're up to," he said.
