Are ground squirrels strictly granivorous?

A ground squirrel with cheeks stuffed with nuts, seeds or grains, is a common sight. But a new study provides the first evidence that California ground squirrels also hunt, kill and eat voles. Researchers have for the first time chronicled widespread carnivorous behaviour among squirrels. The study fundamentally changes our understanding of ground squirrels. It suggests that what was considered a granivorous species actually is an opportunistic omnivore and more flexible in its diet than was assumed. Through videos, photos and direct observations at the regional park, the researchers documented California ground squirrels of all ages and genders hunting, eating and competing over vole prey between June 10 and July 30 this year. The squirrels’ carnivorous summer behaviour peaked during the first two weeks of July, coinciding with an explosion of vole numbers at the park reported by citizen scientists on iNaturalist. This suggests the squirrels’ hunting behaviour emerged alongside a temporary increase in the availability of prey, the study said. The scientists did not observe the squirrels hunting other mammals. There are many questions that remain unanswered, including how widespread hunting behaviour is among squirrels, whether and how it is passed down from parent to pup, and how it effects ecological processes.