Mask markings and color may change with season and age. Ferrets sleep between 15 to 20 hours a day. Ferrets sleep in strange positions. You may find them sleeping face down across the edge of a box with their heads and front legs on the floor. Or you may see them sleeping on their stomachs with their hind legs and tails bent at a 90-degree angle up the side of a box.
Ferrets often sleep together for comfort as well as warmth.
Ferrets are susceptible to the common cold and several strains of human influenza. Ferrets have one central artery in the neck. Some zoologists contend that this midline vessel allows continued blood flow to the brain when the ferret turns its head a full 180 degrees. Ferret vocalizations include mumbles, clucks, hisses and screams. It usually takes two weeks for a ferret to adjust to a new home.