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Do animals have personalities?Among humans, each individual has a unique personality, but so far, scientists have not found or ascribed personality traits, defined as consistent behaviour over time, t

Among humans, each individual has a unique personality, but so far, scientists have not found or ascribed personality traits, defined as consistent behaviour over time, to animals. But a recent study (Animal Behaviour) by a team of researchers from the University of California, Davis, U.S., has been able to document personality in golden-mantled ground squirrels, which are common across the western U.S. and parts of Canada. They found the squirrels show personality in four main personality traits: boldness, aggressiveness, activity level and sociability.

There are no Myers-Briggs tests for animals, but researchers used standardised approaches to quantifying animal personalities. The lead author Jaclyn Aliperti observed and recorded squirrel responses to four tests: (1) Novel environment: Squirrels were placed in an enclosed box with gridded lines and holes; (2) Mirror: Squirrels are presented with their mirror image, which they do not recognise as their own; (3) Flight initiative: Squirrels were approached slowly in the wild to see how long they wait before running away, and; (4) Behaviour-in-trap: Squirrels were caught, unharmed, in a simple trap and their behaviour briefly observed.

According to a University of California, Davis press release, the study found that bolder squirrels had larger core areas where they concentrated their activity. Bold, active squirrels moved faster. Also, squirrels that were bolder, more aggressive and more active had greater access to perches, such as rocks. Perch access is important because it can provide a better vantage point for seeing and evading predators. Interestingly, perch access was also associated with sociability.