GROWTH AND SURVIVAL OF JUVENILE YELLOW-BELLIED MARMOTS (MARMOTA-FLAVIVENTRIS)

We compared patterns of growth in juvenile yellow-bellied marmots (Mar mota flaviventris) between 2 years in which precipitation differed, an d we determined if mass at entry into hibernation affects over-winter survival. Juveniles exhibited an asymptotic growth pattern with mass g ain for a mean of 60.8 days, followed by stable mass until entry into hibernation. Growth ceased in early September, shortly after the end o f the plant growing season. Juveniles born in 1991, a year of late sno wmelt and low summer precipitation, entered into hibernation at signif icantly lower mass than juveniles born in 1992. Juveniles born in 1992 survived better despite experiencing a long winter during which they spent more days in hibernation and lost more mass. Overall, heavier ju veniles were more likely to survive hibernation. Further, mass at entr y into hibernation apparently had a greater effect on over-winter surv ival than did winter severity.