animals that hibernate are in a state of torpor, differing from sleep. hibernation markedly reduces the need for sleep, but does not remove it. some hibernating animals end their hibernation a couple of times during the winter so that they can sleep. hibernating animals waking up from hibernation often go into rebound sleep because of lack of sleep during the hibernation period. they are definitely well-rested and are conserving energy during hibernation, but need sleep for something else.