Squirrels that favor one paw are less 'smart'

Squirrels that favor one paw over the other — compared with those who use both paws interchangeably — are slower learners, the results of a study from the University of Exeter released on Monday showed.

The study, published in the journal Learning and Behaviour, found that grey squirrels with a strong preference for using one side of their body performed worse at tasks that required learning. 

Many animals, similar to humans, have a preferred side of the body for completing certain actions, though the strength of this preference can vary. Some have a clear preference while others are relatively ambidextrous, meaning they can use both sides with equal mastery.

For the love of peanuts

Exeter researchers presented wild grey squirrels found on the university's Streatham Campus with a clear tube that contained peanuts. The tube was too narrow for the squirrels to get at the food using their standard method — their mouths. Instead, they had to learn to use a paw to recover the peanut. 

Researchers tracked the squirrels' speed and which paw they favored to assess their preference and how quickly they learned.

Laterality and cognitive performance

The results push back against a commonly held belief in the scientific community that favoring one side of the body over the other (known as being strongly "lateralized") makes the brain work more efficiently, study author Dr Lisa Leaver said.

Experts had previously argued that being strongly lateralized allowed each hemisphere of the brain to focus on different tasks.

"This could help animals survive, which would explain the evolution of laterality across the animal kingdom," Leaver said. "In fish and birds, there is evidence that being strongly lateralized is linked to better cognitive performance."

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"However, limited data from studies of mammals suggest a weak or even negative relationship," she added, saying that the squirrel data supported the link between strong laterality and poor cognitive performance.

The study calls for further research on the relationship between laterality and cognitive performance in mammals. While the significance of strong laterality in humans is still unclear, initial research suggests that ambidextrous people may be more creative.

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