Are California’s Killer Squirrels Heading To Utah?

Scientists  in California are confirming that a breed of squirrel is not just eating nuts and seeds anymore.

Researchers at U.C. Davis found that ground squirrels are proving to be opportunistic omnivores.

They hunt, kill, and eat smaller rodents and have a particular taste for voles (Voles are small rodents -- usually less than five inches --  and are sometimes known as meadow mice or field mice).

Scientists believe the meat-eating behavior emerged temporarily as the population of available prey increased.

The study was part of the Long-Term Behavioral Ecology of California Ground Squirrels Project, which is conducted at Briones Regional Park in Contra Costa County. The study observed the squirrels' behavior in June and July 2024, when there were more voles than average.

The study found that 42% of the 74 interactions between squirrels and voles involved the squirrels actively hunting and eating the voles. The squirrels were not observed eating any other mammals during this time.

Researchers plan to return to the field in 2025 to see how the vole hunting will affect squirrel reproduction. They are also interested in learning more about the extent of the carnivorous behavior and whether it is passed down from parent to pup.

The study, published in Springer Nature Link journal, doesn't suggest the "killer squirrels" are moving to other ecosystems, but scientists are quick to point out that "just because they haven't done something before, it doesn't mean they won't do it in the future."

“We had never seen this behavior before. Squirrels are one of the most familiar animals to people. We see them right outside our windows; we interact with them regularly,” lead author Jennifer E. Smith, an associate professor of biology at UW-Eau Claire, said. “Yet here’s this never-before-encountered-in-science behavior that sheds light on the fact that there’s so much more to learn about the natural history of the world around us.”

So just because we don't have killer squirrels in Utah right now, doesn't mean we won't have them in the future.

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