Animal researchers in California have discovered human-like personality traits in squirrels that anybody watching one raiding nuts from a bird table could probably have guessed: they are bold, aggressive, athletic and sociable.

The study from University of California, Davis, and published this month in Animal Behavior, claims to be the first to document personality in golden-mantled ground squirrels, prevalent in the western US and Canada.

According to the research, which included a series of scientific tests on the rodents, such as observing how they react to their mirror image, and approaching them in the wild to see how long it was before they ran away, some squirrels are more outgoing than others.

The data, collected over a three-year period, led the analysts to conclude that bolder and more active squirrels covered more ground and were more successful in amassing resources such as food, than their more shy, less active counterparts.

The more aggressive squirrels also had greater access to perches such as rocks, the study revealed, providing better vantage points for spotting and evading predators.

“To see them chitter and skitter, stop and then scurry, the fact that ground squirrels have personalities may not seem surprising,” an introduction to the study on the UC Davis website said.

“But the scientific field of animal personality is relatively young, as is the recognition that there are ecological consequences of animal personality. For instance, bolder, more aggressive squirrels may find more food or defend a larger territory, but their risky behavior may also make them vulnerable to predation or accidents.”

The UC Davis campus is home to a large number of common tree squirrels, a different species from the golden-mantled variety that the university’s wildlife, fish and conservation biology department researches have been studying at Colorado’s Rocky Mountain biological laboratory for more than 30 years.

Lead author Jaclyn Aliperti and her fellow researchers used that data and their own tests to add to what she said was a small but growing number of studies of squirrel individuality.

“Accounting for personality in wildlife management may be especially important when predicting wildlife responses to new conditions, such as changes or destruction of habitat due to human activity,” she said.

“I view them more as individuals. I view them as, ‘Who are you? Where are you going? What are [you] up to?’ versus on a species level.”