IE 11 is not supported. For an optimal experience visit our site on another browser.

The most social dolphins and whales have larger, more complex brains

A study of whale and dolphin brains show it's not size that matters, but socializing. The more social an animal is, the bigger its brain.
/ Source: NBC News

Dolphins and whales speak in accents. They have “hit” songs. They have names for each other and they might gossip.

A new study shows the most social dolphins and whales also have larger, more complex brains.

It’s the latest study supporting the idea that big brains evolved to handle the demands of socializing, and not for some other reason. In other words, humans may be so intelligent because we gossip.

“What we can say for sure with the dolphins and whales is that it’s the groups like the killer whales and the bottlenose dolphins that are doing the really, really interesting things and they are also the ones that have the largest brains,” said Susanne Shultz of Britain’s University of Manchester, who worked on the study.

Baleen whales, which filter tiny shrimp called krill and similar food, have smaller brains relative to their size than pack hunters like dolphins and orcas.

“Blue whales, bowhead whales have small brains. They also seem to move around in loose aggregations,” Shultz added.

“They don’t have long-term, stable relationships. They don’t have lots of complex behaviors.”

Shultz and her colleagues didn’t directly study whales, but instead dug up every scientific study they could find on whale and dolphin behavior. They found tons of it.

“Killer whales (orcas) live in societies of multiple generations and what people have been able to show recently is that older individuals are basically storehouses of information and they pass on this information to younger individuals in times of hardship,” Shultz said.

Dolphin underwater
The new study on dolphins and whales supports the idea that big brains evolved to handle the demands of socializing. In other words, humans may be so intelligent because we gossip.Stephen Frink / Getty Images stock

For instance, they know where to go when the fish disappear from favored hunting grounds.

And they communicate in very sophisticated ways. Whale songs, for instance, come in “dialects”.

“There’s good evidence that sperm whales have fads,” Shultz said.

“What’s really attractive in one year isn’t attractive in another year. It is very much like our culture and our fashion. One population invents a new song and it passes on to other populations.”

Orcas, dolphins and other cetaceans hunt in packs, form alliances, cooperate with other species including humans, babysit one another’s offspring and they eat rich, varied diets.

“In dolphins, there are specific calls that relate to a specific individual,” Shultz said. “It’s like, ‘Hi Joe!’”

And they don’t just use those names in greeting.

“They sometimes seem to use these names when the individuals aren’t there. It could potentially be something like gossip,” Shultz said.

While some whales move about in giant groups, they’re not necessarily interacting in the same way and in fact being part of a giant flock may be a sign of less complex behavior, Shultz’s team reports in the latest issue of Nature Ecology & Evolution.

“Cetaceans found in mid-sized social groups had the largest brains (in both absolute and relative terms), followed by those that form large communities (mega-pods); those predominantly found alone or in small groups had the smallest brains,” they wrote.

While studying animals is interesting on its own, it can also tell us about ourselves, Shultz said.

“For me, the most striking thing is in other animals there are these parallels with humans about how societies evolve,” she said. “If we really want to understand who we are, whales are a good example for understanding why humans became such a complex species.”

Animal studies are showing many species can show striking levels of intelligence. Several apes can use computers to communicate clearly with humans, for example. Birds can not only make use of tools, but plan ahead and store those tools for future use. Elephants recognize themselves in mirrors and seem to enjoy making art.

Scientists argue about what made humans so very much more intelligent and complex in their behavior than other animals. Much evidence points to social interaction, while some experts say it was the ability to cook food and eat meat that gave humans the nutritional edge they needed to grow big brains.

Cetaceans don’t cook, but they are all carnivores, whether their prey is seals or krill. And while some have large brains, others don’t.