Coss - Research
Fig. 1. Juvenile California ground squirrel throws substrate at an approaching northern Pacific rattlesnake. Photograph by John A. L. Cooke published in: Coss, R. G. and Owings, D. H.(1989). Rattler battlers. Natural History 5, 30-35. Substrate throwing is a phylogenetically old motor pattern used to spur rattlesnakes and gopher snakes into striking, rattling, or hissing. California ground squirrels can innately distinguish rattlesnakes from gopher snakes via snake odors and defensive behavior. Further information on this topic can be found in: Coss, R. G., Gusé, K. L., Poran, N. S., and Smith D. G. (1993). Development of antisnake defenses in California ground squirrels (Spermophilus beecheyi): II. Microevolutionary effects of relaxed selection from rattlesnakes. Behaviour 124, 137-164.