A Black Bear (Ursus americanus) in Banff National park, Canada. Climate change poses a threat to bears, who hibernate for around 6 months of the year. During this hibernation their metabolic rate falls by 75 per cent, allowing them to conserve energy. Reports already show bears coming out of their dens earlier in the spring, responding to warming temperatures. An average temperature increase of even one degree can cause hibernating animals metabolic rate to begin increasing earlier in the hibernation period. This leads the bears to burn more fat more rapidly, even while hibernating.