Squirrels adopt orphaned relatives

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London, June 2 (ANI): Like humans, squirrels too have a softer side-the critters adopt orphaned relatives, says a new University of Guelph research.

Led by Andrew McAdam, along with researchers from the University of Alberta and McGill University, the study revealed that red squirrels would adopt pups that have lost their mother.

The finding is significant because while such adoptions are typical among species that live in extended family groups, it is much less common among asocial animals, such as squirrels.

"Social animals, including lions and chimpanzees, are often surrounded by relatives, so it's not surprising that a female would adopt an orphaned family member because they have already spent a lot of time together. But red squirrels live in complete isolation and are very territorial. The only time they will allow another squirrel on their territory is the one day a year when the females are ready to mate or when they are nursing their pups," Nature quoted McAdam, an evolutionary biologist, as saying.

But the study also found that squirrels have their altruistic limits.

They will adopt only if the orphans are related, and even then it's a rare occurrence.

Over two decades, the research team has come across only five cases of adoption.

"That's five cases out of the thousands of litters that have been born since the project began. Adoption does happen, but it's rare," said McAdam.

Jamie Gorrell, a PhD candidate at the University of Alberta, identified 34 cases of potential adoption over 20 years.

An adoption is possible only if the mother dies and a nearby squirrel is also nursing.

"We discovered relatedness plays a critical role in whether a neighbouring squirrel will adopt or not," said McAdam.

In all five adoption scenarios, the pups were nieces, nephews, siblings or grandchildren to the adoptive mother.

"From an evolutionary perspective, the phenomenon of adoption raises the question of why an animal would adopt in the first place given that it jeopardizes the survival of their own offspring. Under the right conditions, an animal can propagate more copies of its genes by helping relatives to raise their offspring than by producing offspring of their own. So in some cases it might be a good bet to adopt and accept these costs," said McAdam.

By examining the breeding records of thousands of squirrels over the past 20 years, McAdam could calculate the costs of adoption.

"What we found was that squirrels will only adopt an orphaned pup when the costs of adoption are low and when the orphans carry a large percentage of the same genes such as siblings, nieces or nephews rather than more distant relatives," he said.

In fact, squirrels can assess which pups are related or not, he added.

The study was published in Nature Communications. (ANI)

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