The short answer is no, animals don’t dream when they hibernate. And that’s because hibernation isn’t the same as sleep.
Sleep is a more physiologically ‘active’ state. Hibernation, in contrast, requires animals (like this dormouse, right) to substantially reduce all activities to conserve energy. Hibernating animals reduce their breathing rate, lower their body temperature and decrease their metabolic rate to around five per cent of their usual levels. There’s simply not enough brain activity while an animal is hibernating to enable dreaming.
There is one exception, however: the fat-tailed lemur. As the only primate to hibernate, scientists have observed them having periods of rapid eye movement (REM) sleep.