Responses to oral gland scents from different males in Columbian ground squirrels

Acrylic cubes carrying oral gland scents from strange, neighbouring, and resident male Columbian ground squirrels (Spermophilus columbianus), plus a cube with no scent, were presented near the home burrows of squirrels in the field. Adult males and adult females sniffed scented cubes longer than unscented cubes, sniffed cubes with scent from other (strange and neighbouring) males longer than cubes with the resident male's own scent, and sniffed cubes with scent from strange males longer than cubes with scent from neighbouring males. Males also scent-marked the cubes on a number of occasions; differences in the frequency with which the cubes were marked followed the same pattern. It thus appears that adult Columbian ground squirrels can recognize familiar as opposed to unfamiliar males, and may also be able to determine individual identity, through oral gland scent. An ability to distinguish familiar from unfamiliar males by scent could be advantageous in facilitating differential treatment of wandering strange males versus established neighbours.