A ferret is a small mammal, usually weighing less than 5 pounds. Females (jills) weigh 1.5 to 2 pounds at maturity and are much smaller than males (hobs), which usually weigh at least 3 pounds and occasionally grow as heavy as 7 pounds. The scientific name for the domestic ferret is Mustela putorius furo, which translates roughly into 'stinky little thief'! Ferrets are not rodents and are not even related to rodents. They are carnivorous animals (meat eaters) biologically similar to cats and dogs.
Neutered males are 'gibs,' and spayed jills are 'sprites,' although hardly anyone actually calls them that. Babies are called 'kits' in North America, but in some countries, notably Australia, they are called 'kittens.'
Where do ferrets come from – are there any wild ones?
Mustela putorius furo, the domestic ferret, has been domesticated for thousands of years, as long as the cat and dog. There are pictures in Egyptian tombs of ferret-like creatures on leashes. Domestic ferrets are biologically related to mink and weasels and to the black-footed ferret, a wild, weasel-like animal native to North America. All of these animals are called 'mustelids' because their anal glands secrete a strong smelling musk.
The first domesticated ferrets probably originated from captive breeding of wild polecats, which still exist in Europe and Asia. Ferrets are smaller than polecats, and although the two species can be cross-bred and produce hybrid babies, they are genetically different. After thousands of generations of domestication, ferrets have no inherent fear of man, and cannot survive without human aid. There are no wild ones anywhere.
Ferrets are much smaller and more agile than cats and can follow rodents into smaller holes. This was probably the reason people thought of catching polecats, breeding them, and keeping the friendliest ones in their homes and barns. About 300 years ago, the first ferrets worked their way to North America from Europe, controlling rodents on the ships of the early colonists. There are still a few ferrets on rat patrol in dairy barns and ships in Canada and the U.S. Although hunting with ferrets is illegal in America now, they have been used to hunt burrowing animals such as rabbits and groundhogs. The ferret does not usually kill the prey: it chases or frightens it out of the burrow where it is captured or killed by some other means. Occasionally ferrets are 'hired' to pull electric or telephone wires through long ducts too small for more conventional methods to be efficient.
There are two basic colors of ferrets: sable and albino. Albino ferrets have pure white fur and pink eyes. The albino condition is genetically recessive to sable, so if a sable female that carries no albino gene is bred to an albino male, all the kits will be sable, but will carry the albino gene. When sable ferrets carrying the albino gene are bred to each other, 25% of their offspring may be albino. Breeding sables to albinos does not produce white ferrets with dark eyes: the dark-eyed white color is associated with a different set of genes.
All kits have white hair at birth, but albinos remain white, while colored ferrets turn gray during their first week of life. Although white markings can be distinguished, kits do not have a distinctive coat color until they are about 4 weeks old. Even then, their adult color cannot accurately be predicted.
Sable ferrets look very much like wild polecats. They have black legs and tail, with a mixture of white or yellow underfur and dark brown or black guard hair on their bodies. (Guard hair is the longer, shinier, surface hair that gives the coat its characteristic color and pattern.) The dark mask around their eyes gives sable ferrets a distinctive appearance. A kit develops its mask at about 2 weeks of age, but has a vertical band of dark hair between its eyes until it is mature. The presence of this 'baby band' distinguishes a young ferret from an adult.
Ferrets shed their coats (molt) spring and fall, and colored ferrets change color when they molt. Some have a distinctly different summer color, and return to the original color with the fall molt.
There are many mutations of coat color in ferrets, producing a wide range of shades and patterns. Some colors and patterns have been selected by breeders because they make pet ferrets more distinctive. The new colors and patterns have been given special names, which are somewhat standardized in North America, but not in other countries.
Siamese is just a lighter color phase of sable. Siamese ferrets have brown hair where sables have black – the pattern is similar to that of Siamese cats.
People who show ferrets have given names to different shades of sable and Siamese. For instance, butterscotch is a very pale shade of Siamese, cinnamon is a very red Siamese, and chocolate is rich, dark brown. In the UK, Siamese ferrets of an even butterscotch color are known as 'sandies.' A black sable has almost no light hairs in its coat, and from a distance appears solid black.
Silver ferrets are silver all over, with no distinct division in color between their bodies and feet. When young, these ferrets might look sable or Siamese, but they often have small spots of white on their hind legs, and there will be some white hairs in their coats if you look hard. Silvers fade with time, becoming whiter with every molt, until they are almost pure white.
Silver mitts have pure white paws – these markings can be distinguished at birth because the skin is unpigmented. A young silver mitt may be appear to be sable or Siamese with white feet, but more white appears in the coat with every molt. Some silver kits are almost pure white, with only a few dark hairs down the middle of their backs or on their heads, and even these vanish with a few molts.
A white streak between the ears of a sable or Siamese ferret is called a blaze. This may be so wide that most of the head is white, and the ferret has no mask at all, just a narrow ring of color around each eye. At ferret shows these are called pandas. Pandas may have white mitts, and many have white around their necks ('bibs') or on their chests or bellies. Many have small patches of white on the fronts of their hind legs ('headlights'). Panda markings may be associated with congenital deafness.
Dark-eyed ferrets that are born and remain pure white are known as black-eyed or dark-eyed whites to distinguish them from albinos.
Occasionally, odd-colored ferrets are born. They may have rings of white on their tails, one or more white toes on each foot, or dramatic patches of color on a white body. However, by the time they are 3 or 4 years old, these ferrets have faded to silver or white, and the odd markings are usually indistinguishable.
How long do ferrets live?
The average ferret that is fed a good diet and receives regular veterinary care lives 6 or 7 years. Some live to be 8 or 9 and occasionally even older. Ferrets that are allowed to go outside are at much greater risk of injury and disease than inside pets.
For more information on coat colors and patterns see: http://www.ferret.org/events/colors/colorchart.html