Researchers reason why sperm whales have different dialects
Dialects is something that has long been associated with humans with very few direct observations of groups of same animals having differing dialects. However, that has changed in a new study that examines this aspect in sperm whales.
Mauricio Cantor, a PhD candidate in biology, at Dalhousie University claim through a new study that sperm whales not only have different dialects, but these dialects are governed by their cultural inclination. Cantor notes in the study that despite sharing the same geographical area, sperm whales develop unique communication signals or “dialects” composed of patterns of clicking sounds called coda and that the difference in dialects can be attributed to culture.
Culture is seen as human-only feature by many scientists and is said to influence development of different dialects across the globe. There is a fraction of scientists who believe that animals also have culture and that’s what governs their behaviour and development. A debate is raging on between the two sides of the aisle in this regards.
According to Cantor, development of different dialect in the same geographical area has been seen in humans and broadly speaking, comes as a result of cultural evolution. To check if this is the case with sperm whales as well, he carried out a study of the ocean dwelling creatures to find out what might be at play.
Cantor and others in the research team first conducted a field trip wherein they listened for the whales’ clicking sounds with an underwater microphone to nail down their locations and study their coda repertoires. The team also photographed each of the sperm whale’s tails as they came to the surface to breathe, about every 40 minutes. This is because the ridge of the tail is a sperm whale’s equivalent to a fingerprint. Using all this information, they matched codas and behaviours to individual sperm whales.
Post the extensive field work, the team combined the data with previous Whitehead Lab data dating as far back as the ‘80s to create virtual populations of whales using computer simulations.
Using the actual data and results of computer simulations, Cantor and the team backtracked patterns they had observed to infer how the clan may have segregated and evolved over the last three decades.
“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”, Cantor said.
The researchers simulated several scenarios with virtual populations of whale to see how the two clans observed during the field work would have developed the different dialects. They examined the data to look for answers to how the dialects would evolve if the whales created codas by themselves; how the dialects would evolve if they innately knew which codas to produce; and when whales could listen and copy the codas they hear from other whales.
Cantor and team found that biased social learning is a required ingredient for the segregation of clans of sperm whales with different dialects. This is says based on the computer simulations that made it clear that whales are learning how to communicate from each other. The whales in each clan are conforming to those most similar around them, they found.
“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,” says Cantor. “Maybe we’re not as different as we thought.”
Other experts are of the opinion that Cantor’s findings will effectively fuel the ‘culture in animals’ debate and even make tourists more aware about the debate too.