Some animals may wake to poop during hibernation, they may also eat small amounts of food during this time. However, a lot of animals, like bears, won't go to the toilet at all when they’re hibernating. It was originally thought that they managed this by essentially blocking their digestive systems with materials that are difficult to digest, such as plant matter and hair, which forms a poop plug. However, it’s since been discovered that the body continues producing waste at a slower rate, and this plug is actually dried-up fecal matter.