Squirrels noshing on nuts is a common sight, but don't be fooled -- they're apparently no vegans. Scientists looking into the habits of the California ground squirrel have discovered that the species is actually a bona fide meat eater, "killing and decapitating en masse," as SFGate puts it, recently in the Bay Area to get their carnivorous fix. Their meat of choice? That of their fellow rodent, the tiny vole, according to new research published Wednesday in the Journal of Ethology, which shows "the first documented evidence of the [squirrel] consistently eating meat," reports Gizmodo.

Scientists who've been studying the California ground squirrel for more than a decade had previously classified it as a grain eater, partial to seeds, grains, and vegetation. That changed, however, when the research team out of the University of Wisconsin-Eau Claire and UC Davis observed further squirrel behavior in June and July at Briones Regional Park in California's Contra Costa County. They found that in 74 encounters with voles, squirrels hunted, killed, and ate them in 42% of those interactions, per CNN. Jennifer Smith, the study's lead author, calls their findings "shocking."

"We had never seen this behavior before," she says in a release, adding, per SFGate: "Seeing the videos was astounding and shifted my perspective on a species that I have spent the last 12 years of my life studying." Co-author Sonja Wild concurs, adding, "I could barely believe my eyes." The study describes a gory process, in which the squirrels "first removed the head of the vole," then "either directly pulled meat out of the torso or first stripped fur from each of the body parts before consuming the exposed meat, organs, and cartilage."

The researchers believe this recent meat-eating spree may be an environmental adjustment, based on a rapidly increasing vole population. The squirrels "simply took advantage of superabundant prey," Smith says, per SFGate -- a phenomenon known as "dietary plasticity," notes CNN. Scientists continue to marvel at their find, though some questions, including just how widespread this behavior is, remain unanswered. "Squirrels are one of the most familiar animals to people," Smith notes in the release. "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." (More discoveries stories.)