Behavioral Ecology Advance Access originally published online on September 22, 2004
Behavioral Ecology 2005 16(1):280-285; doi:10.1093/beheco/arh162
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Foraging time of rutting bighorn rams varies with individual behavior, not mating tactic
Département de biologie, Université de Sherbrooke, 2500 boulevard de l'Université, Sherbrooke, Quebec, J1K 2R1 Canada
Address correspondence to F. Pelletier. E-mail: fanie.pelletier{at}USherbrooke.ca.
Mate guarding is the primary mating tactic used by dominant males of many species of ungulates. Guarding males are thought to forage less during the rut than do nonguarding males, possibly leading to greater fitness costs. I observed bighorn rams foraging during the pre-rut and the rut. I compared how coursing (an alternative mating tactic) and tending (a form of mate guarding) affected the foraging behavior of bighorn rams over the rut, to test whether foraging was more constrained by mate guarding than by coursing. All adult males spent less time feeding during the rut compared with the pre-rut. The decrease in time spent feeding, however, was independent of mating tactic. Contrary to expectation, individual rams observed both coursing and tending spent less time foraging when coursing than when tending. For young rams, the time spent in rutting activities was correlated with individual pre-rut mass, indicating that males either modify their behavior according to available metabolic reserves or adjust the energy devoted to rutting activities to the level of expected benefits. Mate guarding does not appear to constrain foraging more than coursing. The costs of male reproductive behavior may depend more upon individual effort than on the particular tactic adopted.
Key words: bighorn sheep, feeding constraint, Ovis canadensis, rut.