According to a study published on Oct. 16 in “Nature Ecology and Evolution,” cetaceans, like whales and dolphins, grew larger brains much like humans in order to better live in societies.
This process is known as encephalization and “has given [humans] the big brain we need to communicate, cooperate, reach consensus, empathize, and socialize.”
Our brains have evolved and expanded over millennia to accommodate our developing, complex needs and those of our societies. Apparently, we aren’t the only mammals who have experienced this biological evolution.
Michael Muthukrishna, an economic psychologist at the London School of Economics and co-author of the study, noted that two related theories, the Social-Brain Hypothesis and the Cultural-Brain Hypothesis, were used to predict various relationships between brain size, societal organization, and behaviors displayed by the cetaceans. They then compiled a comprehensive list of the unique behaviors observed in 90 different species of dolphins, whales and porpoises, and found that the bigger the species’ brain, the more complex (and “human-like”) their lives tend to be.
The cetaceans have intricate networks of communities with their own unique ways of communicating. They work together and play together. They’re even able to work with other species, namely humans. They can look after friends’ children and teach each other how to use tools. Some have unique regional group dialects, or songs, and can mimic the sounds of others.
The study also showed that killer whales, otherwise known as orcas, live in societies consisting of multiple generations where the older individuals are able to pass on information they learned over time to the younger individuals. An example of such knowledge is passing down the knowledge of where an individual should go when the fish disappear from favored hunting grounds.
Susanne Schultz, an evolutionary biologist at the University of Manchester and lead author of the study, pointed out that the killer whales and the bottlenose dolphins groups exhibited the most interesting behavior in addition to having the largest brains.
“The apparent co-evolution of brains, social structure, and behavioral richness of marine mammals provides a unique and striking parallel to the large brains and hyper-sociality of humans and other primates on land,” she said.
Although there are plenty of exciting behaviors and correlations to be found in these animals, Schultz does bring up a good point. As cetaceans have obvious physical limitations, there are major differences between their own development and humans. While cetaceans have both complex behaviors and an advanced society, they are without “simple tools and rudimentary architecture.” Therefore, although they are quite evolved as a species, they may never reach the evolutionary status that humans have.
However, Muthukrishna enjoys studying them for this exact reason. He says that because cetaceans are so alien to us, they are capable of offering unique insights to us and our society. He studies the evolution of and the processes that underlie human culture. Because of this, he believes learning more about this nature in other creatures can allow us more insight into human behavior.
Muthukrishna indicates that the problem with using primates as a comparison is that he doesn’t know if what he finds is because of proposed evolutionary logic or because these features just happen to be present in an ancestor. For instance, human ancestors and chimp ancestors may have lived in communities and had large brains for entirely unrelated reasons; but because cetaceans are evolutionarily distant from humans, they are a unique marker for this type of behavior.
Studying the processes that underlie the evolution of whales and dolphins can ultimately aid researchers identify the correlations between physical circumstances such as living on land or being similarly built, and what factors directly influence prosocial and cultural behaviors.
Featured image via Wikimedia Commons
