It’s easy to imagine that a cute little squirrel is merely a threat to nuts, but it turns out they may have a more bloodthirsty bent than we knew.
After 12 years of studying squirrels in California, a team of scientists observed them actively hunting and killing small rodents this past summer.
California ground squirrels eat primarily acorns, seeds, nuts, and fruit, but they may also consume insects and bird eggs.
There was also evidence that they ate meat on occasion, but it was unclear if they were simply scavenging dead animals or actively hunting them.
We now have clear visual and video evidence (see below) that it is the latter. The Long-term Behavioral Ecology of California Ground Squirrels Project has been observing the animals in Briones Regional Park every summer since 2013, and this year, some unexpected new behavior surfaced.
During 18 observational days in June and July 2024, the researchers witnessed hundreds of ground squirrels actively seeking and/or preying on smaller rodents known as California voles. It wasn’t just one lunatic squirrel going rogue; males and females, adults and juveniles all took part.
Of the 74 documented encounters between the two species, 31 involved the squirrels actively hunting the voles. The squirrels usually took advantage of an opportunity to chase a vole across a short distance in an open area, but a few stalked and stealthily ambushed their prey.
Out of the 31 hunting attempts witnessed, 17 resulted in a successful kill, usually accomplished with a few fast bites to the neck.
In 70% of cases where the squirrel won, they were witnessed transporting the dead vole elsewhere to devour it. They always started by removing the head, then either pulling meat from the torso or removing the fur before eating.
“This was shocking,” said Jennifer Smith, the study’s co-lead author. “We had never witnessed this conduct before. Squirrels are among the most familiar creatures to humans. We see them right outside our windows and engage with them frequently.
Yet here’s this never-before-seen-in-science behavior that highlights the reality that there’s still so much to learn about the natural history of the world around us.”
So, if the team has been regularly monitoring squirrels for more than a decade, why hasn’t this behavior been observed before? This year, it appears that vole populations in the area and elsewhere in California have expanded, and the ever-adaptable squirrels were most likely simply taking advantage of the abundant new food source.
After all, the study claims that no squirrels were witnessed hunting any other creatures throughout the observation period.
“The fact that California ground squirrels are behaviorally flexible and can respond to changes in food availability might help them persist in environments rapidly changing due to the presence of humans,” said Sonja Wild, the study’s co-lead author.
The researchers say they’re looking forward to next year’s observation period to see if this hunting behavior repeats itself, if it can be passed down through generations, and what effect it has on squirrel reproduction compared to previous years.
