Squirrels are adorable creatures that are famous for stuffing their cheeks with nuts. Usually, these small mammals consume nuts, seeds, fruit, and even fungi. However, a new study has found evidence that California ground squirrels will sometimes hunt, kill, and consume voles.
Opportunistic Omnivores
The study, which was led by the University of Wisconsin-Eau Claire and the University of California, Davis, was published in the Journal of Ethology, found that these small squirrels, who were once believed to be completely granivorous, are actually opportunistic omvivores.
Observing California Ground Squirrels
The study, which took place between June 10 and July 30, 2024, used videos, photos, and direct observations to study California ground squirrels’ interactions with voles. It found that squirrels of all ages and genders were hunting, eating, and competing with each other over these small rodents.
Familiar Animals
They recorded 74 interactions between squirrels and voles. 42% of these encounters involved squirrels actively hunting and consuming the voles. Jennifer E. Smith, an associate professor of biology at UW-Eau Claire, spoke about their findings, saying, “This was shocking. We had never seen this behavior before. Squirrels are one of the most familiar animals to people.
Natural History
“We see them right outside our windows; we interact with them regularly. 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.”
Confusion
Initially, Sonja Wild of UC Davis was confused when undergraduate students told her what they had found. She had never heard of anything like it before. When she watched the videos, she couldn’t believe her eyes. “From then, we saw that behavior almost every day. Once we started looking, we saw it everywhere.”
Increased Availability
In recent years, voles’ numbers have increased significantly around Briones Regional Park, where the study was conducted, leading researchers to believe that the squirrels’ hunting behavior occurred because of an increased availability of prey. This suggests that squirrels might be opportunistic omnivores.
Behaviorally Flexible
“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 of UC Davis.
An Abundant Resource
John Koprowski, the dean of the Haub School of Environment and Natural Resources at the University of Wyoming, mentioned that squirrels need protein to thrive, and catching voles provides them with a faster and more accessible nutrition boost than seeds. “It’s a wonderful way for them to capitalize on a very abundant resource … to provide enough sustenance for many (squirrels) to use,” he said.
It Is Normal
Koprowski mentioned that a change in diet is very normal for animals. Voles are considered pests, and having a new predator like squirrels will keep their numbers under control. But this new behavior might not stop there.
Helping Future Research
According to Smith, the findings in this new study may help future research on the adaptability of different squirrel species and other mammals as they adapt to environmental changes.
A Human-Impacted World
“Animals can either adapt or go extinct in a human-impacted world,” Smith said. “These animals are showing us the incredible resilience of some species, and by studying these processes, we can offer meaningful insights for conservation.”
Many Unanswered Questions
Researchers still have many unanswered questions about this discovery. For now, they are not sure how widespread this behavior is. They also do not know how it is passed down from parents to pups and what its effect will be on ecological processes. The authors are excited to return to the field next summer to learn more about this unexpected behavior.
