THIS report comprises the results of preliminary investigations on the ability of rattlesnakes to perceive airborne odors of two types; attractives in the form of food including its various stages of putrefaction, and repellent odors in the form of scents of three animals feared by these reptiles. This research was supported by a research grant from the Richfield Oil Corporation. The subsidiary objectives of the first phase of these investigations included tests as to the acuity and utility of chemoreception, and degrees of acceptance of putrifying protein as a source of food. Also involved was the