The   ferret   is   a   domesticated   mammal,   with   males   being substantially larger than females. They typically have brown, black, white,  or  mixed  fur  and  have  a  natural  lifespan  of  7  to  10 years. Ferrets are crepuscular, meaning they spend 14–18  hours  a  day asleep,  and  are  most  active  around  dawn  and  dusk.  Unlike  their polecat  ancestors,  which  are  solitary  animals,  most  ferrets  will  live happily  in  social  groups. They are territorial, like to burrow, and prefer to sleep in an enclosed area.  A group of ferrets is commonly referred to as a "business."