Vole hunting: Novel predatory and carnivorous behavior by California ground squirrels

Описание: After an unusual peak of California voles in summer 2024, we observed 74 occasions of California ground squirrels hunting and consuming voles at our long-term field site at Briones Regional Park, California, in just under two months.

California ground squirrels are largely granivorous. Their diet is primarily made up of fresh greens, seeds and nuts. They have been known to occasionally supplement their diet with meat from carcasses, through nest predation on eggs and young birds and there have been isolated reports of them killing small prey such as lizards. However, widespread active hunting and killing of mammalian prey has never been observed in this species.

Vole hunting likely emerged in response to an unusually high peak in numbers of California voles around our field site. California voles undergo population cycles that peak every 3-5 years. Data from the citizen science app iNaturalist, on which people can record sightings of wildlife, showed that the numbers of California voles in 2024 peaked at about 7 times the 10-year average. We suspect that the overabundance of voles provided relatively easily accessible prey for the squirrels and is likely the reason for the emergence of this widespread predatory behavior.

Our study highlights the behavioral flexibility of this species, in that they can dynamically respond to changes in their environment by switching their diet from eating mainly grains and fresh greens to consuming quite large amounts of meat (facultatively omnivorous). Such behavioral flexibility can be very helpful in prevailing in changing environments, which is particularly important in the modern world when humans can cause very rapid changes to animals' environments.

Credit: Team Squirrel - University of Wisconsin-Eau Claire & UC Davis
Link to the study:
https://doi.org/10.1007/s10164-024-00...