First record of squirrels evolving into carnivorous animals

Dec. 18 () –

a new research developed in California has been the first to record widespread carnivorous behavior among squirrels.

Published in the Journal of Ethologythe study fundamentally changes our understanding of ground squirrels, according to the authors. It suggests that what was considered a granivorous species is actually an opportunistic omnivore and more flexible in its diet than previously assumed.

The observations occurred in 2024, the twelfth year of the California Ground Squirrel Long-Term Behavioral Ecology Project conducted at Briones Regional Park in Contra Costa County. Of the 74 interactions observed with flies between June and July, 42% involved active hunting of these small rodents by ground squirrels.

“This was shocking,” he said. in a statement lead author Jennifer E. Smith, an associate professor of biology at the University of Wisconsin-Eau Claire who directs the long-term ground squirrel project with Sonja Wild of the University of California Davis. “We have 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. However, here is this behavior never before seen in science that sheds light on the fact that there is much more to learn about the natural history of the world around us.”

Through videos, photographs and direct observations In the regional park, the authors documented California ground squirrels of all ages and genders hunting, eating, and competing for vole prey between June 10 and July 30. The carnivorous behavior of squirrels in summer peaked during the first two weeks of Julycoinciding with an explosion in the number of voles in the park reported by citizen scientists on iNaturalist. This suggests that squirrels’ hunting behavior emerged alongside a temporary increase in prey availability, according to the study. The scientists did not observe squirrels hunting other mammals.

“The fact that California ground squirrels have flexible behavior and can respond to changes in food availability pcould help them persist in environments that change rapidly due to the presence of humans,” Wild said.

Smith added that many species, including the California ground squirrel, are “incredible opportunists.” From raccoons and coyotes to spotted hyenas and humans, the flexibility these mammals apply to their hunting strategies helps them change and adapt to the human landscape.

The researchers said many questions remain unanswered, including how widespread hunting behavior is among squirrels, whether it is passed from parents to offspring and how it affects ecological processes.