December 27, 2024, 9:40 am | Read time: 4 minutes
When you think of squirrels or chipmunks, many people have an image in their head of a rodent that loves to stuff nuts into its cheek pouches. However, that doesn’t seem to be the only thing these animals like to eat. As a study has shown, there are also carnivorous ground squirrels that hunt voles. A never before documented behavior.
Looking around the squirrel family, you probably expect to see cute rodents with big dark eyes and a bushy tail. For many, they are the epitome of cuteness, but the view of these popular rodents could change in the future. Some were known to eat animal protein in the form of insects. However, carnivorous ground squirrels with an appetite for voles were not compatible with the image people have of them. However, a study now shows us how little we actually know about the animals’ diet.
A New Look at Hunting Ground Squirrels
California ground squirrels have always been known as herbivores whose diet consists mainly of seeds, grasses, and herbs. In the case of ground squirrels, meat consumption has so far only been documented in the form of insects or occasional nest predation.
However, a study led by Jennifer E. Smith from the University of Wisconsin – Eau Claire and Sonja Wild from the University of California, Davis, shows a different picture. The long-term study by the two researchers and their colleagues has been running since 2013. In the twelfth year of this study, the unusual behavior of the ground squirrels first came to light.
In just two months in the summer of 2024, 74 cases were documented in which gophers hunted, killed, and ate native voles. This behavior occurred in a year when the vole population was exceptionally high. This suggests that the gophers adapted their feeding strategy to a sudden food supply, as the researchers write in their study published in the Journal of Ethology.
If There Are Too Many Voles, Ground Squirrels Help Themselves
This observation, made for the first time in the wild, could turn our understanding of this animal species’ feeding habits and flexible behavioral adaptations on its head. But why did these otherwise mainly herbivorous animals suddenly turn to hunting?
To find out, we first need to take a closer look at the population spikes of the California vole. Peak periods, when the animals reproduce more frequently than usual, occur approximately every three to five years. This means that the ecological conditions also change fundamentally for the carnivorous ground squirrels in these “vole years.”
42 percent of the incidents investigated involved active hunting, with the ground squirrels often killing their prey by chasing it in open areas. They were successful in 55 percent of hunting attempts. This makes the carnivorous ground squirrels nearly as efficient as the black-footed cat, the world’s deadliest small wild cat, which has a success rate of 60 percent.
Carnivorous Ground Squirrels Show Sophisticated Hunting Strategy
After successful hunts, the ground squirrels usually carried their prey to another location before starting to eat. Often, the head of the vole was removed first. In addition to hunting, there were also 13 documented cases of competition for already killed voles. Some of these were characterized by pursuit and aggression.
It was striking that both adult and juvenile gophers of both sexes were involved in these activities, with no discernible demographic trend. Interestingly, the hunting events were also not limited to areas with high vole densities. Instead, they often took place in areas where ground squirrels were particularly abundant, indicating opportunistic adaptation.
These results fundamentally change how researchers assess the flexibility of rodents. They show that the animals are able to react flexibly to sudden food offers. This is the case even if these are not part of their typical food spectrum. The ability to actively hunt and consume larger prey is an adaptation that could offer the animals a great advantage.
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Have We Always Misunderstood Squirrels?
Prior to this discovery, the species was thought to be predominantly granivorous (herbivorous), with only rare reports of meat consumption. However, advanced hunting strategies have shown to be a common behavior that is not just a short-term adaptation. This is also shown by the frequency and social aspects of this new behavior.
The ability to actively hunt and consume larger prey is an adaptation that no one would have previously thought rodents capable of. This is particularly relevant for science, as it calls into question previous assumptions about the animals’ ecological niche. After all, if ground squirrels can become opportunistic, carnivorous hunters under the right conditions, they may be much more adaptable than previously thought.
In the long term, the results of this study could fundamentally change our understanding of the diet and evolutionary abilities of rodents. This could happen as soon as other species are better studied and similar behavior is documented in them. Further research is also needed to understand the exact causes and ecological consequences of meat consumption in rodents. 1