When it comes to brains, size matters!
Scientists have found that carnivores that have larger brains relative to their body size perform better in problem-solving tasks.
The researchers travelled to nine different zoos in US and presented 140 animals from 39 different mammalian carnivore species with a novel problem-solving task.
The study included polar bears, arctic foxes, tigers, river otters, wolves, spotted hyenas and some rare, exotic species such as binturongs, snow leopards and wolverines.
Each animal was given 30 minutes to try to extract food from a closed metal box. To access the food, an animal had to slide a bolt latch, which would allow a door to open.
The box was baited with the favourite food of the study animal, so red pandas received bamboo and snow leopards got steak.
The main result is that species with larger brains relative to their body size were more successful than species with relatively smaller brains.
"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," said lead author Sarah Benson-Amram, assistant professor at the University of Wyoming in US.
"Overall, 35 percent of animals (49 individuals from 23 species) were successful in solving the problem. The bears were the most successful, solving the problem almost 70 percent of the time," said Ben Dantzer from the University of Michigan.
"Meerkats and mongooses were the least successful, with no individuals from their species solving the problem," Dantzer said.
Interestingly, larger animals were less successful overall than smaller-bodied animals. The study also shows that manual dexterity did not affect problem-solving success.
In addition to examining the influence of brain size on problem-solving abilities, the researchers also studied whether species that live in larger average group sizes are more successful problem solvers.
"A hypothesis that has garnered much support in primate studies is 'the social brain hypothesis,' which proposes that larger brains evolved to deal with challenges in the social domain," said senior author Kay Holekamp, from the Michigan State University.
"This hypothesis posits that intelligence evolved to enable animals to anticipate, respond to and, perhaps, even manipulate the actions of others in their social groups," Holekamp said.
"If the social brain hypothesis is correct, then we would expect that species that live in larger social groups would be more intelligent," he said.
"However, we did not find any support for the social brain hypothesis in this study. There was no indication that social group size influenced problem-solving abilities," he said.
The study was published in the journal PNAS.
