Ferrets lives 6-8 years on average (sometimes up to 11 or 12). Females are called jills, and males are hobs. Baby ferrets are called kits. In North America, spayed females are sometimes called sprites and neutered males called gibs. A group of ferrets is a "business of ferrets." Males tend to be larger than females in length and weight. Most ferrets obtained in North America are spayed or neutered and descented at a very young age before being sold. Ferrets sleep a large part of the day, commonly around 18 hours. They naturally tend to be active at dawn and dusk, but usually adapt their sleeping and active times to the fit the schedules of their owners. Ferrets are very playful, and are very entertaining to watch. Ferrets have relatively poor eyesight but a keen sense of smell and hearing.