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Tuesday, June 15, 2010

Red squirrels adopt young of relatives

From Africa Geographic via their facebook page

Red squirrels found adopting young of relatives

At first glance, this picture of a red squirrel tenderly cradling a baby seem incredibly touching, but according to research in Canada this is more about survival than altruism.

University of Alberta’s Jamieson Gorrell had been watching a red squirrel population in Yukon when he came across a female that had adopted a newborn squirrel abandoned by its biological mother.

The adoptive mother had taken the baby from its nest back to another in a nearby tree where she then cared for it.

Squirrels are among the most solitary animals, having little to do with one another, so the adoption of a foundling struck Gorrell as an anomaly. But while checking through nearly 20 years of research gathered by the university on the squirrel population, he made a breatkthrough discovery.

On four other occasions, over the life of the study, female red squirrels had adopted abandoned baby squirrels and, in every case, Gorrell found that the foundling was related to its adoptive mother.

Unlike social animals such as chimpanzees, the solitary, anti-social squirrels were able to identify kinship without making contact with one another.

The researchers think that before the biological mother disappeared the adoptive mother to be, recognized a genetic link between them. Gorrell’s team theorized that the constant vocalizing *or* chattering a squirrel uses to mark its territory and ward of intruders contains signals describing its genetic history. The adopting mother knew the biological mother was family and after it disappeared she recognized her genetic connection to the abandoned baby.

This research is significant because it proves a long-accepted theory of evolutionary biology is correct for a solitary, non-social animal. Hamilton’s Rule, dating back to 1963, explains that despite the so-called law of the jungle and survival of the fittest, altruistic behavior can exist. But this altruism is restricted to family members only.

Female red squirrels will only adopt an abandoned baby it shares common genes with and will pick only one lucky squirrel from an entire litter.

Gorrell says that having an extra family member helps the adopting mother ensure a continuation of the gene pool. But adopting more than one would be out of the question because the costs to the adoptive mother and her own biological offspring outweights any potential benefit.

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