Scientists have discovered that Californian ground squirrels are developing in a ‘shocking’ way: the animals have developed a taste for meat.
Dozens of them hunting, attacking and feasting on rodents have been captured on video for the first time.
The bizarre behavior was on display for two weeks at Briones Regional Park in Contra Costa County, as cameras recorded squirrels pouncing on their prey, tearing them apart and eating the lifeless animal.
On one occasion, scientists watched in horror as a squirrel ‘forcefully’ shook its prey while holding it in its mouth.
The observations have suggested that these nut-foraging creatures are evolving into carnivorous predators.
“This was shocking,” said Dr. Jennifer E. Smith, an associate professor of biology at the University of Wisconsin-Eau Claire, who led the study.
‘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 are in regular contact with them.
“Yet here is this behavior never before seen in science, shedding light on the fact that there is so much more to learn about the natural history of the world around us.”
Squirrels are known for stuffing their cheeks with nuts. But scientists have captured shocking footage of California ground squirrels hunting and eating rodents
Scientists observed 74 interactions between squirrels and voles, which are similar to hamsters, from June 10 to July 30.
And more than 32 of those exchanges ended with the squirrel feeding on the small animal.
The predator typically restrained the rodent with its forelimbs and teeth, and then delivered one or more bites, killing the bites on the neck.
In three of the recorded hunting attempts, squirrels stayed low to the ground and chased their prey.
Nineteen squirrels chased voles across the landscape, which was usually followed by a jump to contain the prey.
Then the squirrels would go for the kill.
Although they mainly targeted bites on the neck, they sometimes went for other body parts as well, the researchers noted.
The squirrels successfully captured and killed a field mouse 55 percent of the time.
Scientists have captured shocking footage of California ground squirrels hunting, killing and then eating voles
Squirrels have traditionally been considered ‘granivorous’ animals (animals that feed on grain), but the new footage adds to the evidence suggesting squirrels are becoming carnivorous
The scientists were observing the squirrels at Briones Regional Park in Contra Costa County when they noticed the unusual behavior
These carnivorous eating habits coincided with an explosion of voles in the park.
According to the researchers, this suggests that their hunting behavior was accompanied by a temporary increase in vole availability.
This nutritional flexibility may give the squirrels a survival advantage.
Sonja Wild, a behavioral ecologist at UC Davis and author of the study, said in a statement: ‘The fact that California ground squirrels are behaviorally flexible and can respond to changes in food availability could help them persist in environments that are rapidly changing due to the presence of humans.’
Although the researchers have been studying squirrels for years, even they were surprised by the findings.
“I could hardly believe my eyes,” Wild added.
‘We saw that behavior almost every day.
“Once we started looking, we saw it everywhere.”
“This research radically changes our perception of squirrels, one of the most well-known mammals in the world,” said lead author Dr. Smith. CNN via email.
Between June 10 and July 30, they were amazed to see California ground squirrels of all ages and sexes hunting, eating and competing for voles.
Of the 74 observed interactions with field mice, almost half (42 percent) involved active hunting of these small rodents by ground squirrels
‘In the face of human insults such as climate change and drought, these animals are resilient and have the potential to adapt to life in a changing world.’
The researchers published their findings in the Journal of Ethology.
Although this is the first time California ground squirrels have been documented hunting rodents, previous research has found evidence that they eat bird eggs, invertebrates and certain species of rabbits, gophers and rats.
But those studies found no evidence that the squirrels hunted and killed these animals.
Other studies have reported that California ground squirrels eat captured fish, meat, woodrats, songbirds, and in one case, another adult squirrel.
A few studies have found evidence that this squirrel species hunts and kills other animals.
Those reports identified captive side-spotted and western fence lizards, northern broad-footed moles, and possibly a domestic chicken as prey.
In addition, infanticide – the direct killing of young young – has also been extensively documented in California ground squirrels.
‘For example, forty murders of young ground squirrels have been documented in four years; In at least 22 of these cases, youth were cannibalized,” Wild and co-authors wrote in their report.
According to the researchers, several questions about the new eating behavior remain unanswered.
This includes how widespread the behavior is among squirrels, how and whether it is passed from parent to pup, and how it affects ecological processes.
But the team plans to return to the park next summer to see if there has been a long-term impact on the field mice or the squirrels themselves.