The ferret (Mustela putorius furo) belongs to the family of Mustelidae. It is thought that it derives from the skunk (Mustela putorius), of which it represents the domesticated form. Reared by man for at least 2000 years to be used in hunting, from a behavioural point of view, the ferret is to all effects a domestic animal, well adapted to living with humans. The ferret is usually an amenable animal, with a lively, playful and very affectionate character that makes it an excellent pet. Furthermore, it is clean, quiet and relatively easy to manage, in part because of its small size. Its average life expectancy is 7-8 years, although it may reach 11 years old. On average, European ferrets live longer than their American counterparts.
BEHAVIOUR
Ferrets are lively, curious animals, which are usually docile (although some subjects may bite because of behavioural problems or previous maltreatment). They love the company of people and other ferrets (Fig. 1) to play with and are attention-seekers. By nature, this mustelid is a crepuscular animal, but in a household it tends to adapt its rhythm to that of the family. The ferret is normally active for about one quarter of the day and sleeps for the rest of the time. It sleeps deeply, such that it is sometimes difficult to wake it up and the owner becomes concerned that the animal is unwell (Fig. 2). When the ferret is left free it should always be watched carefully and it is preferable to leave it safely in its cage while it sleeps. One typical behaviour of this animal is to hide food at various points around the house, with the risk that the food rots without the owner being aware. The ferret is usually quiet but when playing it can produce whistles, chirps and soft clucks (dooking). If it feels pain it may squeal or moan.
DOMESTIC MANAGEMENT
The ferret is a very lively and active animal. It loves exploring, running, playing and interacting with people and should not, therefore, be kept in a cage at all times. Nevertheless, a cage is essential in order to restrain the animal temporarily when it cannot be left free in safety or when it is asleep in order to keep it protected.
The cage must be very large, escape-proof, robust and easy to wash. The best material is steel. The minimum size for a pair of ferrets should be 1.5 m x 0.5 m x 0.5 m. Cages extending upwards can be used, with several floors connected by ramps or tunnels, to increase the space available to the animals. Various accessories can be placed in the cage, such as a little house or hammock (Fig. 3), tunnels, the litter tray, drinking bottle, and food container. Most ferrets, like cats, can be easily trained to use a litter tray, which should be filled with gravel or sawdust. The bottom of the cage must not be covered with substances such as wood chippings and sawdust; rags can, however, be used.
The ideal environmental temperature is 15-21°C. Ferrets tolerate cold well, but not excessive heat: environmental temperatures above 30°C can cause heat stroke and death.
The place in which ferrets are left free must be made safe and checked carefully to eliminate any danger. Ferrets are active, inquisitive animals that love investigating everything; they can squeeze into tight spaces and escape or put themselves into dangerous situations. It is very important to keep out of reach of ferrets anything that could harm them, such as electrical wires, detergents, cigarettes and drugs. Rubber, soft plastic and similar substances (toys, sponges, rubber erasers, pipe insulation material, kitchen gloves, cushion stuffing, etc.) are particularly dangerous for ferrets, especially young ones, which are irresistibly attracted to them and tend to shred them into pieces and swallow them, leading to intestinal obstruction. A few litter trays should be placed in the environment in which the ferret is left free, preferably in the corners.
A ferret can be taken outside, provided that it is under close control to prevent it from escaping and from being attacked by dogs. A lead attached to a chest harness can be used to prevent the animal from running away.
A ferret readily lives together with other ferrets, particularly if the group is formed while the animals are still young. Ferrets are not compatible for cohabitation with rabbits, rodents and birds.
PROPHYLAXIS
Ferrets must be vaccinated against distemper from the age of 6 weeks, with boosters every 3 weeks until the age of 14 weeks. Subsequently, boosters should be given annually for the animal’s whole life. The vaccines used for dogs are safe, provided they are not cultured on ferret cells.
If necessary, these animals can be vaccinated against rabies using killed vaccines for dogs and cats. The vaccine should be given starting from 3 months of age with annual boosters. Live vaccines must not be used because they can cause the disease.
The ferret is not susceptible to mink enteritis virus, canine parvovirus-associated gastroenteritis, canine hepatitis virus, feline leukaemia virus and feline virus-associated gastroenteritis and respiratory tract diseases and does not, therefore, need to be vaccinated against these infections.
In areas in which heartworm is present, prophylaxis should be performed using the same products and methods as those used in the dog.
STERILISATION
Pet ferrets must be sterilised. Sexually intact males give off a particularly intense odour and can be aggressive; both problems are eliminated by orchiectomy. Jills that are not spayed readily develop an oestrogen-induced fatal anaemia (hyperoestrogenism) if they remain in heat without mating.
Ferrets from breeding farms are sold already sterilised. Those from amateur breeders are often sold intact and must be sterilised towards the end of the winter following their birth. The jill can be spayed even if she is already in heat provided that this has not started more than a month previously; otherwise, a full blood count must be performed to ensure that problems of hyperoestrogenism have not already begun. Some authors suggest replacing surgical sterilisation, in both sexes, by chemical sterilisation (by implanting deslorelin) to avoid the possible development of adrenal disease.
Asportation of the anal sacs to reduce the odour emitted by mustelids is useless and can damage the anal sphincter. The odour given off by these animals derives from the cutaneous sebaceous glands, which are under the influence of the sex hormones and the odour is, therefore, controlled only by sterilisation.
LEGISLATION
errets are sold freely and do not need particular documents. From a legislative point of view the ferret is considered a domestic animal to all effects and it is, therefore, prohibited to release these animals into nature or abandon them. Ferrets are subject to the same legal obligations as dogs to cross the Italian border: implantation of a microchip, a passport, vaccination against rabies at least 1 month prior to departure and a certificate of good health. In the north-east of Italy, where vaccination against rabies is compulsory in dogs, this vaccination is recommended in ferrets but is not obligatory.