EFFECT OF PREDATOR ODORS ON HEART-RATE AND METABOLIC-RATE OF WAPITI (CERVUS-ELAPHUS CANADENSIS)

We measured the heart rate (HR) and oxygen consumption (V-O2) of wapit i (Cervus elaphus canadensis) before, during, and after presentation o f biologically irrelevant odors (pentane, thiophene, and a perfume), a rtificial predator odors (an ether extract of cougar feces, and PDT, a compound found in mustelid anal gland secretion), stale predator odor s (dog feces and urine and fox urine, kept at ambient temperature for a few weeks), and fresh predator odors (wolf, coyote, and cougar feces and the odor of a dead coyote, kept frozen between collection and tes t). Overall, responses to odors were small compared to other stressful stimuli. Individual variability was high among scents and among wapit i, but two of the fresh predator odors (cougar and wolf feces) produce d larger HR and V-O2 responses than the other scents and were more oft en successful at producing responses. As a group, fresh predator odors produced larger tachycardias and elicited a larger number of signific ant HR responses than biologically irrelevant novel odors, although th e two classes of odors did not differ in their effect on V-O2. Althoug h several other studies have shown that ungulates have reduced feeding levels when their food is scented with predator odors, it is not clea r if this is due to reduced palatability or antipredator behavior. Thi s study is the first demonstration that a wild ungulate species reacte d more strongly to predator odors than to other odors in a nonfeeding situation.