Heterogeneity in risk-sensitive allocation of somatic reserves in a long-lived mammal

Patterns of food quality and availability, when combined with energetic demands in seasonal environments, shape resource acquisition and allocation by animals and hold consequences for life-history strategies. In long-lived species with extensive maternal care, regulation of somatic reserves of energy and protein can occur in a risk-sensitive manner, wherein resources are preferentially allocated to support survival at the cost of investment in reproduction. We investigated how Rocky Mountain bighorn sheep (Ovis canadensis), an alpine mammal in a highly seasonal environment, allocate somatic reserves across seasons. In accordance with the hypothesis of risk-sensitive resource allocation, we expected accretion and catabolism of somatic reserves to be regulated relative to pre-season nutritional state, reproductive state, and vary among populations in accordance with local environmental conditions. To test that hypothesis, we monitored seasonal changes of percent ingesta-free body fat (IF...