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California Ground Squirrels Caught Hunting Voles in a Carnivorous Twist

In an unexpected discovery that challenges our understanding of these familiar backyard residents, researchers have documented California ground squirrels actively hunting and consuming other mammals – specifically, voles – in what appears to be widespread carnivorous behavior.

Published in Journal of Ethology | Estimated reading time: 4 minutes

Picture a ground squirrel, and you’ll likely imagine its cheeks stuffed with nuts or seeds. Yet a groundbreaking study from the University of Wisconsin-Eau Claire and University of California, Davis has revealed these seemingly herbivorous creatures in a startling new light: as active predators capable of hunting and killing other rodents.

“This was shocking,” says lead author Jennifer E. Smith, an associate professor of biology at UW-Eau Claire. “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. Yet here’s this never-before-encountered-in-science behavior.”

The discovery emerged during the 12th year of a long-term study at Briones Regional Park in Contra Costa County. During June and July 2024, researchers documented 74 interactions between ground squirrels and voles, with 42% involving active hunting. The behavior peaked during early July, coinciding with an unusual surge in the local vole population.

The hunting strategy employed by the squirrels proved surprisingly sophisticated. While most attempts were solo endeavors, the squirrels displayed various techniques: some stalked their prey by staying low and minimizing noise, while others engaged in direct pursuit. Upon catching a vole, the squirrels typically targeted the neck area and, in successful kills, would often carry their prey to a different location before consuming it.

Postdoctoral research fellow Sonja Wild of UC Davis’s Environmental Science and Policy department initially found the reports hard to believe. “I could barely believe my eyes,” she recalls. “From then, we saw that behavior almost every day. Once we started looking, we saw it everywhere.”

This adaptability might prove crucial for the species’ survival. “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,” Wild noted.

Glossary

  • Omnivore: An animal that consumes both plant and animal material as their primary food source
  • Granivorous: Feeding mainly on seeds and grains
  • Behavioral Flexibility: The ability to adapt behavior in response to environmental changes

Test Your Knowledge

What percentage of the observed squirrel-vole interactions involved active hunting?

42% of the 74 observed interactions involved active hunting of voles by ground squirrels.

During which month did the hunting behavior peak?

The hunting behavior peaked during the first two weeks of July.

What hunting strategies did researchers observe the squirrels using?

Squirrels used various strategies including stalking by staying low and minimizing noise, direct pursuit, and targeting the neck area of their prey when catching them.

How does this discovery change our understanding of ground squirrel behavior and adaptation?

The study reveals that what was considered a primarily granivorous (seed-eating) species is actually an opportunistic omnivore with significant behavioral flexibility, capable of adapting its feeding strategies in response to food availability.


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6 thoughts on “California Ground Squirrels Caught Hunting Voles in a Carnivorous Twist”

  1. When u experience all the same traits u describe in a 2 lb. squirrel, in a creature the size of a human, u must really become panic stricken, yes?

  2. @Carel Two-Eagle I think it’s less that they will eat other animals and more that they employ sophisticated hunting techniques! Not simply opportunistic.

  3. Anyone who hunts squirrels knows they eat baby birds, so this “finding” is not “shocking” – EXCEP to city people who never get out to hunt. Disney be damned!

  4. This makes me fear the little bandits even more! There are a few overly friendly ones where I work, and they simply are not frightened by humans. They will follow you as you walk to your car in the evening. Now I know they just want the taste of blood!

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