Slaves to fashion: Canadian researcher uncovers the secret life of sperm whales
Posted April 14, 2016 2:56 pm.
Last Updated April 15, 2016 8:40 am.
This article is more than 5 years old.
HALIFAX – New research reveals there’s more to being a sperm whale than deep diving, eating giant squid and being as big as a city bus.
These lumbering behemoths may have their own distinct dialects and cultures — and prefer other whales that are most like themselves, according to a marine researcher at Dalhousie University in Halifax.
After analyzing 30 years of underwater recordings, PhD candidate Mauricio Cantor has found sperm whales learn to communicate from their peers and relatives, in much the same way that humans do.
“They prefer to interact with those that communicate using the same sounds that they do … and we call these vocal clans,” he says.
“Even though they are very different from us, they have key similarities with our society, in terms of having families, having social preferences and also communicating using similar sounds.”
When near the surface of the ocean, typical sperm whales emit clicking noises that sound like a stick being raked across a series of metal bars — a kind of staccato Morse code.
Researchers have long known that these sounds have patterns associated with separate populations of sperm whales.
Cantor’s research, however, goes much deeper than that.
Using recordings that date back to the 1980s, Cantor created computer simulations of whale populations spread over many centuries. The technique generated evidence suggesting communication within these large groups is the product of social learning.
“The most likely scenario is that they are learning from their peers. They are conforming to the most common sounds they hear, just like us. They tend to copy what is in fashion.”
The fascinating result, he says, is segregated whale cultures that are not unlike the various human cultures around the globe.
“We usually interact more with those who are similar to us. I hope that finding the similarities with other animal societies can improve our relationship with the natural world — with the whales and other animals.”
Among the tropical Galapagos Islands off Ecuador, Cantor studied two clans that shared the same area but were segregated because they didn’t share the same dialect — a phenomenon that is rare in the animal kingdom but easy to recognize among people.
“One (clan) has very regular clicks, very evenly spaced, and the other has clicks that include long pauses … with one click at the end,” says Cantor, a 32-year-old biology student who is originally from Brazil.
“It’s the same way for us. It’s more likely for me to interact with someone who speaks English or Portuguese, which is my native language, than someone who is Russian or another language.”
The clicks, produced in the whale’s large forehead, are also used to find food through a process known as echolocation — the same radar-like method bats use to find prey.
Cantor, under the direction of renowned marine biologist Hal Whitehead, helped record sperm whale sounds between 2012 and 2014.
Typically, he would spend three weeks aboard a 12-metre sailboat with up to five other researchers, working in shifts 24 hours a day — tracking, listening and recording.
“We’ve had some very exciting encounters. A whale came about a half metre from the boat and checked us out, rolling on its side. You could see it looking at our faces.”
Other sperm whales tried to bite the underwater microphones trailing behind the boat.
He’s not the only Dalhousie researcher trying to learn more about sperm whale culture.
Christine Konrad, a 24-year-old Dalhousie student who is also preparing a thesis on the marine giants, says her own work is focused on how different groups behave when hunting squid and travelling, among other things.
“I think a better understanding of the social structure of sperm whales helps us put ourselves and our own society and culture in context,” the student from Burnaby, B.C., said in a recent email from the Caribbean, where she was conducting field research near the island of Dominica.
“It makes us realize we aren’t the only ones with complex relationships that extend beyond simply who you are related to. And I hope that realization helps people relate to a species other than our own.”
Cantor says he’s aware that his findings will fuel a simmering debate over the notion that cultural evolution is exclusive to humans.
Still, he says the evidence is there, based on the idea that culture — in its simplest form —is behaviour that is learned from other individuals.
“I’m not saying that whale culture is as complex as human culture, but at least the (sperm whales) have these two main features.”
– with files from Melanie Patten