Animals With Bigger Brains Are Better Problem Solvers, Study Confirms

It seems like a no-brainer: Animals with bigger brains, relative to their body size, are better problem solvers. That's the consensus from University of Wyoming researchers who recently devised a test of problem-solving skills for carnivorous animals that involved freeing food from inside a metal box.

For their study, researchers from the University of Wyoming and colleagues presented their novel puzzle boxes to 140 carnivores from 39 species in North American zoos. The animals – ranging from polar bears to arctic foxes, tigers and river otters, among others – were given 30 minutes to extract the food, according to a news release. To open the box and access the food, animals had to figure out how to slide a bolt latch. Each box was baited with a favorite food. For instance, red pandas received bamboo, while snow leopards got steak.

On the whole, animals with larger brains relative to body mass were better at opening the boxes and retrieving the food than those with relatively smaller brains. Larger animals were less successful than smaller-bodied individuals.

Interestingly enough, manual dexterity did not seem to correlate with problem-solving success.

"Overall, 35 percent of animals (49 individuals from 23 species) were successful in solving the problem," Ben Dantzer, study co-author from the University of Michigan, explained in the release. "The bears were the most successful, solving the problem almost 70 percent of the time. Meerkats and mongooses were the least successful, with no individuals from their species solving the problem."

"This study offers a rare look at problem solving in carnivores, and the results provide important support for the claim that brain size reflects an animal's problem-solving abilities – and enhance our understanding of why larger brains evolved in some species," Sarah Benson-Amram, lead author and an assistant professor in the Department of Zoology and Physiology at the University of Wyoming, added in the university's release.

Researchers also examined whether or not living in large groups factored into problem solving – what is known as the social brain hypothesis, which suggests that intelligence evolved to enable animals to anticipate, respond to and even manipulate the actions of others in social groups, researchers say.

"If the social brain hypothesis is correct, then we would expect that species that live in larger social groups would be more intelligent. However, we did not find any support for the social brain hypothesis in this study," Kay Holekamp, co-author and professor from Michigan State University, said. "There was no indication that social group size influenced problem-solving abilities."

The study was recently published in the Proceedings of the National Academy of Sciences.