Ontogenetic and seasonal changes in diet in the yellow-bellied marmot: an explanation from optimal foraging theory [Variations ontogénétiques et saisonnières du régime alimentaire de la marmotte à ventre jaune : une explication de la théorie de l'affouragement optimal].

Résumé

Diet selection in the yelIow-bellied marmot (Marmota flaviventris) was studied at two sites in Montana during 1991 and 1992. A linear programming (LP) model (Belovsky 1986) successfully predicted diet selection (grass versus forb) for most months. Adult, yearling and juvenile marmots all selected diets consistent with the predicted goal of energy maximisation. Towards the end of the active season, the LP model underetimated the amount of grass in the diet. Possible reasons for this are discussed.