Sperm Whale Communication: What All the Chatter Means
Sperm whales are very social marine animals. They travel in close groups and communicate by using a pattern of clicks, also known as codas. Similar to humans, the whales use varying dialects worldwide. A recent study of two sperm whale clans living in fairly close proximity off the Galápagos Islands, sheds light on animal cultures.
"Culture in animal societies is a highly debated topic," Mauricio Cantor, a Ph.D. candidate in biology at Dalhousie University in Halifax, Canada, said in a news release. "Some experts think it's clear enough, while others don't think the word 'culture' should be used describing anything but humans."
Cantor explained that it is rare to observe two clans of the same species that live so close to one another, but communicate differently. This segregation, common in human populations, comes as a result of cultural evolution. Cantor has been studying these sperm whales since 2013, with the help of Professor Hal Whitehead from the university's department of biology.
Together, Cantor and Whitehead used an underwater microphone to listen to the sperm whales' clicking sounds, and located differing codas. To associate codas to specific sperm whales, they would photograph their tails when they surfaced to breathe every 40 minutes. From this, the researchers were able to create virtual populations of whales using computer simulations and by incorporating additional whale data that dated back to the 80s.
"We try to backtrack the patterns we observe in the wild to infer how the clan segregation could have evolved," Cantor explained in the release. "The computer will simulate the life of several sperm whale populations that acquire codas in different ways over thousands of years. At the end, we see which case could produce clans with different dialects."
In order to further understand how the different dialects were created, Cantor simulated three varying scenarios within the virtual populations. This included individual learning, genetic transmission and social learning.
"Our findings show that biased social learning is a required ingredient for the segregation of clans of sperm whales with different 'dialects'," said Cantor in the release, further explaining that these findings suggest that whales are learning how to communicate from each other. Also, he said, they conform to those most similar around them. This is very similar to how humans learn in varying cultures.
"This gives us evidence that key features of human culture -- which we think makes us so different from everything else in nature -- might be at play in populations of other animals," Cantor added in the release. "Maybe we're not as different as we thought."
Their findings were recently published in the journal Nature Communications.
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