Behaviors Associated with the Novel Hunting of California Voles by California Ground Squirrels : Quantifying Animal Behavior to Examine Novel Hunting

Abstract

Natural selection is expected to favor foraging behaviors that allow animals to maximize energy gain in novel situations. Whereas many species are known to regularly hunt prey and eat meat, squirrels are largely considered to be flexible omnivores that consume mainly grasses and seeds. However, our team recently documented the widespread hunting of California voles (Microtus californicus) by California ground squirrels (Otospermophilus beecheyi). This novel behavior is unusual for the species and has not been studied before. Here, we analyze the behavior of ground squirrels during these predation events (N=22 events). We characterized the hunting sequence for the first time in the California ground squirrel. We define hunting as the active pursuit of prey. We know that some mammalian hunters (cursors) chase prey over distances whereas sit-and-wait predators use stealth to ambush prey. We found that California ground squirrels were successful in 59% of their hunts, typically chasing, pouncing, and then biting the neck or head of the vole before consuming it. Revealing these opportunistic patterns of behavior contributes to our broader understanding of mammalian hunting styles.