Ground squirrels evolved to eat voles

Associate Professor, Dr. Jennifer Smith, University of Wisconsin, Eau Claire, and her colleagues discovered that California ground squirrels repeatedly hunt and eat voles by biting the head and tearing flesh from the body of the prey. According to them, this is a shocking discovery. Although ground squirrels have been observed eating insects, bird eggs, newly hatched chicks, and even the carrion of small, immature mammals, they are essentially herbivores, specializing in seeds. acorns, fruit, according to Guardian.

“This finding is especially exciting because it is the first time we have documented active hunting behavior from start to finish in ground squirrels. Once we witnessed the behavior occur, it was continuous repeat throughout the summer,” Smith said. However, this is not the first time California ground squirrels have hunted like this. Female squirrels can eat the young of their own species.

In a paper published Dec. 18 in the journal Ethology, Smith’s team describes how they made the discovery in the 12th year of a long-term study of the California ground squirrel population in Briones Regional Park in Contra Costa County, California state. Every June and July, they set live traps, mark, tag, and release ground squirrels to identify individuals. Over 18 days in the summer of 2024, the team recorded 74 events in which ground squirrels hunted or ate voles, with at least 27 different squirrels engaging in such behavior. Both adult and juvenile squirrels, male and female, hunt voles and often do so alone. Sometimes, they try to mix up each other’s vole corpses.

The researchers also noted that this unexpected behavior coincided with an unusual explosion in the vole population in California, according to scientific data from local residents. They still don’t know the reason behind the behavior. “It seems that squirrels are just opportunistic animals,” Smith said. She also does not rule out the possibility that they learn their behavior from each other. According to Smith, California ground squirrels are known for being flexible in their feeding behavior. The abundance of voles during the summer actually expands their foraging range.

The research team concluded that the new findings reveal that California ground squirrels can be considered opportunistic omnivores. This could help them survive in the face of challenges such as climate change and human presence.