Why do ferrets sleep so much?

Ferret natural instincts in the wild spend most of their time in dens underground to avoid predation. Ferrets spend 15 to 18 hours a day sleeping depending on their age. Baby kits and older ferrets sleep more. They are naturally crepuscular, meaning they are most active during dusk and dawn. Ferrets sleep more than most animals, but when awake they are very hyper, and will want to be of their the cage ready to play and explore. The older a ferret is, the longer they will sleep.

Some ferrets will sleep more out of boredom, if they are not properly stimulated. They need more time out of their cage and more playtime.