EAST LANSING, Mich. --- The brains of wild cats don't necessarily respond to the same evolutionary pressures as those of their fellow mammals, humans and primates, indicates a surprising new study led by a Michigan State University neuroscientist.
Arguably, the fact that people and monkeys have particularly large frontal lobes is linked to their social nature. But cheetahs are also social creatures and their frontal lobes are relatively small. And leopards are solitary beasts, yet their frontal lobes are actually enlarged.
So what gives? Sharleen Sakai, lead investigator of the National Science Foundation-funded research, said the findings suggest that multiple factors beyond sociality may influence brain anatomy in carnivores.
"Studying feline brain evolution has been a bit like herding cats," said Sakai, MSU professor of psychology and neuroscience. "Our findings suggest the factors that drive brain evolution in wild cats are likely to differ from selection pressures identified in primate brain evolution."
Sakai and colleagues examined 75 wild feline skulls, representing 13 species, obtained from museum collections, including those at MSU. The researchers used computed tomography (CT) scans and sophisticated software to digitally "fill in" the areas where the brains would have been. From that process, they determined brain volume.
Sakai's lab is interested in uncovering the factors that influence the evolution of the carnivore brain. One explanation for large brains in humans and primates is the effect of sociality. The idea is that dealing with social relationships is more demanding than living alone and results in bigger brains, especially a bigger frontal cortex.
"We wanted to know if this idea, called the 'social brain' hypothesis, applied to other social mammals, especially carnivores and, in particular, wild cats," Sakai said.
Of the 13 wild feline species examined, 11 are solitary and two - lions and cheetahs - are social.
Here are some of the key findings of the research:
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The study, published online in the journal Frontiers in Neuroanatomy , was co-authored by MSU researchers Ani Hristova, Elise Yoon and Barbara Lundrigan; and Bradley Arasznov of Minnesota State University.
Frontiers in Neuroanatomy