California ground squirrels stun scientists with their unexpected carnivorous behaviour, hunting voles in a surprising display of adaptability

In a startling twist to our understanding of California ground squirrels, researchers have discovered these seemingly harmless nut enthusiasts hunting and eating voles. Published in the Journal of Ethology, the groundbreaking study reveals an entirely new side to these animals, suggesting they may be opportunistic omnivores rather than strict granivores.

The revelation comes from a study conducted by scientists at the University of California, Davis, who observed 74 interactions between ground squirrels and voles during June and July 2024. More than 42% of these encounters involved active hunting by the squirrels, a behaviour previously unrecorded.

“This was shocking,” said Jennifer E. Smith, an associate professor of biology and lead author of the study. “We had never seen this behaviour before. It sheds light on the fact that there is so much more to learn about the natural world.”

The discovery initially left researchers incredulous. When undergraduate students presented video evidence of the behaviour, Dr Smith admitted she could “barely believe” her eyes. “From then, we saw that behaviour almost every day. Once we started looking, we saw it everywhere,” she added.

The study documented a range of carnivorous activities, from hunting and consuming voles to competing over prey. Researchers noticed the peak of this behaviour during the first two weeks of July, coinciding with a significant rise in vole populations in a local park.

While the carnivorous activities seemed tied to the abundance of voles, scientists observed no evidence of squirrels targeting other mammals. This led them to theorise that the behaviour may have emerged as a response to a temporary food surplus.

“This flexibility in diet and behaviour could help California ground squirrels adapt to environments increasingly altered by humans,” noted Sonja Wild, another author of the study.

The findings align ground squirrels with a group of mammals known for their opportunistic survival strategies, such as raccoons, coyotes, and spotted hyenas. These animals demonstrate remarkable adaptability to changing food availability, which often aids their survival in human-dominated landscapes.

However, the study leaves numerous questions unanswered. Researchers now aim to investigate the broader implications of this behaviour. They want to determine how widespread this predation is among squirrel populations and whether it is a learned behaviour passed from parent to offspring.

Moreover, the interaction between squirrels and voles could have ecological consequences. Researchers are particularly interested in how this newfound predation might influence the transmission of diseases between the two species.

“Although we observed no signs of disease in our study population, these behaviours could influence host-parasite dynamics,” the researchers concluded.

The discovery not only challenges the stereotypical image of squirrels as nut-loving foragers but also raises intriguing questions about their ecological roles and adaptability. As researchers delve deeper into these mysteries, one thing is certain: the natural world continues to surprise us in shocking and unexpected ways.