Reproductive strategies of yellow-bellied marmots: Energy conservation and differences between the sexes

Yellow-bellied marmots (Marmota flaviventris) conserve maintenance energy by reducing resting metabolic rate, decreasing conductance, avoiding thermal stress, by an annual cycle of metabolism, and by reducing metabolic rate and conductance following the mid summer molt. Male reproductive strategies include successful dispersal and locating females, establishing a territory and shifting energy use to summer defense, becoming polygynous and including as many females as possible within the territory, spending more time aboveground, and hibernating in the area where females are present. The major female reproductive strategy is the formation of matrilines, which facilitates the acquisition of resources, increases reproductive output, and provides a reproductive competitive advantage. Females also share space and are amicable with close kin, are agonistic toward all other females, may suppress the reproduction of other females, including their daughters, and produce daughter-biased sex ratios when recruitment of daughters is highly probable. Conflict occurs between males and females because female competition limits the number of females that reproduce whereas male reproductive success increases directly with the number of females weaning litters.