Endangered Species: Large Brains May Cause Extinction Faster, Says Study

Greater brain size might not be such a terrific thing after all -- in fact, it could be one of the several factors that bring an animal closer to extinction (along with overhunting, fragmented habitats, pollution and climate change), one study says.

The study findings were recently published in the journal Proceedings of the Royal Society B.

This might come as a surprise, considering that research has generally demonstrated that a bigger mass of gray matter could help an animal solve problems in an altering environment.

And it's true that as a landscape becomes colder, certain animals might not be able to grow thicker fur but can work out other solutions -- like building a warmer nest or spending more time in the sun, noted senior author Eric Abelson, who worked on the study as a doctoral researcher, with Rodolfo Dirzo at Stanford University, in a release.

However, the tradeoff to this is that an animal needs to eat more or expend fewer calories in order to balance out the energy required to grow neural tissue.

If the animals are having to maintain such a balance, they might take a bigger one-two punch from other pressures related to extinction, including scarcity of resources. Either that, or their brains may not be able to solve all problems: Mind-power might not aid a water-dwelling animal that has a home in polluted waters, for instance.

The study looked at the measure of absolute brain size in comparison to body size (called relative brain size) for several hundred mammal species alive today. Then Abelson compared this information with the endangerment status of those mammals, according to the International Union for Conservation of Nature's (IUCN) list. In that comparison, it was revealed that species that have bigger relative brain sizes had a greater likelihood of being threatened with extinction.

In the same comparison, smaller mammals that had a bigger relative brain size were the worst off.

"Right now, conservation efforts could benefit from better predictions of which animals might become endangered in the future," Abelson said in the release. Currently he works as a researcher at the Pacific Southwest Research Station of the U.S. Forestry Service. "Understanding the role that relative brain size plays in endangerment risk might give us another tool to identify the animals that might face trouble down the road."

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