Antisnake Behavior of Columbian Ground Squirrels (Spermophilus columbianus)

Abstract

Wild-caught Columbian ground squirrels ( Spermophilus columbianus ) were video taped during interactions with a rattlesnake ( Crotalus viridis ), gopher snake ( Pituophis melanoleucus ), and Norway rat ( Rattus norvegicus ) in a seminatural laboratory setting. Columbian ground squirrels differentiated the rattlesnake from the gopher snake, initially exhibiting more cautious behavior in the presence of the rattlesnake. As the encounters escalated, the rattlesnake became the target of significantly more investigative and harassment behavior than the gopher snake. In contrast, the squirrels did not exhibit cautious behavior toward the rat; they typically chased and boxed it. Columbian ground squirrels exhibited most of the antisnake motor patterns previously reported for other ground squirrel species, but the antisnake tactics of these squirrels were less confrontational than tactics employed by California ground squirrels ( Spermophilus beecheyi ) and black-tailed prairie dogs ( Cynomys ludovicianus ).