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June 28 (UPI) – A larger brain is not always a winning evolutionary strategy. The mountain beaver offers the latest evidence that sometimes it makes sense to sacrifice brain power for other benefits.
Today, the mountain beaver, Aplodontia rufa spends most of its time in underground tunnels. But new research suggests that his closest ancestor lived in the trees.
The 30 million-year-old ancestor of the rodent also had a smaller body and a larger brain. Over time, fossil evidence now suggests, the beaver became nocturnal and took underground layers. The mammal's vision became less important and, as a result, the neocortex of the mountain beaver narrowed.
Mountain Beavers always have a bigger brain than their parents, but they are significantly smaller. Ornella Bertrand, a postdoctoral fellow at the Department of Anthropology at the University of Toronto Scarborough, said in a press release that her metabolism is expensive, which means she needs a lot of money. Energy to work. "Parts of the brain that are not crucial for survival could have been chosen."
Mountain beavers can still climb trees, and sometimes do, but without the brain and vision, they are not as capable
"There seems to be a relationship between being arboreal – that's it. that is to say, living in trees – the size of the neocortex and a strong vision, "said Bertrand
. the size of brains in domestic animals, including dogs, pigs and chickens, but the phenomenon is rare in wild animals.
Mountain Beavers are found in the Pacific Northwest and parts of southern British Columbia. Like their more famous cousins, the North American Beaver, mountain beavers eat wood. However, they do not cut trees or build dams. Instead, they chew small trees and live in underground burrows, like marmots.
Researchers have detailed their analysis of the mountain beaver brain in the journal Palaeontology.
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