Social learning and not genetic inheritance explains sperm whale groupings

A team of biologists and physicists from universities in Canada, the United States and the Philippines revealed that it is biased social learning and not genetic inheritance or pure social learning that accounts for the groupings of sperm whales. 

Their discovery, published recently in the high impact international journal Nature Communications, drew the attention of over 30 news outlets including Time, Washington Post, Newsweek, Nat Geo, Discovery, Smithsonian, BBC News, CBC News, NBC News, Nature, and Science.

UP’s own Dr. Reniel Cabral of the National Institute of Physics is part of the team.

“I am proud that a Philippine institution is included in a paper published in one of the world’s top [academic] journals,” he said in an article on the GMA Network website. “I hope that the Philippines will continue fostering international collaboration by supporting the research of students and academic institutions.” 

Three distinct social levels were seen within the Pacific sperm whale society – individuals, social units and vocal clans – during yearly field work in the Eastern Pacific Ocean from 1985 to 2003.

With data from these 18 years, the researchers then trained an algorithm to determine the origin of sperm whale clans. They tested genetic inheritance, individual learning and social learning as possible reasons for their emergence.

They saw that the algorithm, an agent-based modelling, gives distinct clans when social learning with homophily and conformism were factored in. These clans possess the same acoustic repertoires.

Specifically, they observed that a combination of two modes of cultural transmission is needed to match empirical evidence: when calves copy adults in social units that have similar repertoires (homophily) and when these calves copy the most common repertoires (conformism).

Neither genetic transmission (i.e., the transfer of acoustic repertoires from mother to calves) nor the copying by calves of acoustic repertoires from each other was sufficient to produce distinct clans. 

The authors suggested that the clans emerged as a result of cultural segregation and put into spotlight the debate on whether the processes that drive culture and social structure in humans also happen in non-human societies.

This debate is “a crucial step towards evaluating the contrasts and convergences between human and non-human cultures,” they said.