Killer squirrels caught devouring voles for dinner in shock footage that reveals rodent is a blood-thirsty meat eater

FORGET the nuts - squirrels have developed a taste for meat, according to shock new footage.

The rodent has been spotted by stunned scientists hunting and feeding on voles.

Ground squirrels are considered a granivorous species, eating seeds and grains.

But it turns out they're more of an opportunistic omnivore with flexible diets that includes other eating animals.

During an observation in California this year, squirrels were seen chomping on voles.

And it wasn't just a one off either - out of 74 tracked by scientists between June and July, four in ten were spotted actively hunting.

Those documented varied in age and gender - and even competed for the tiny creatures.

"This was shocking," admitted lead author Jennifer E. Smith, associate professor of biology at the University of Wisconsin-Eau Claire.

"We had never seen this behaviour 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 behaviour that sheds light on the fact that there’s so much more to learn about the natural history of the world around us."

Dr Sonja Wild from the University of California, Davis has studied hundreds of squirrels in nature and wasn't even sure what the students were referring to when they flagged it.

"I could barely believe my eyes," she said.

"From then, we saw that behaviour almost every day. Once we started looking, we saw it everywhere."

The strange development peaked during the first two weeks of July, when an explosion of vole numbers where reported at Briones Regional Park in Contra Costa County, California.

This has led scientists to believe that the squirrels' new hunting came about due to temporary surge in availability of juicy prey.

Throughout their research, the squirrels were not caught feeding on any other mammals.

But experts say there are many questions still to answer - are these types of hunting tendencies widespread and how do squirrels learn about it.

"The fact that California ground squirrels are behaviourally flexible and can respond to changes in food availability might help them persist in environments rapidly changing due to the presence of humans,” Wild added. 

The study was published in the Journal of Ethology.