Ferret biology and health concerns
Ferrets do not require frequent bathing, which may remove natural oils in the ferrets coat that prevent dry skin. However, most ferrets are not averse to water. Ferrets also need their nails clipped about once a month, and usually shed twice a year in the spring and fall.
Like many other carnivores, ferrets have scent glands near their anuses, the secretions from which are used in scent marking. It has been reported that ferrets can recognize individuals from these anal gland secretions, as well as the sex of unfamiliar individuals. Ferrets may also use urine marking for sex and individual recognitions.
As with skunks, ferrets can release their anal gland secretions when startled or scared, but the smell dissipates rapidly. Most pet ferrets in the US are sold descented, with their anal glands removed. In many other parts of the world, including the UK and other European countries, descenting is considered an unnecessary mutilation.
Males, if not neutered, are extremely musky. It is considered preferable to delay neutering until sexual maturity has been reached, at approximately six to eight months old, after the full descent of the testicles. Neutering the male will reduce the smell to almost nothing. The same applies for females, but spaying them is also important for their own health. Unless they are going to be used for breeding purposes, female ferrets will go into extended heat and a female that will not mate, without medical intervention, can die of aplastic anemia. It is possible to use a vasectomised male to take a female out of heat.
Many domestic ferrets are known to suffer from several distinct health problems. Among the most common are cancers affecting the adrenal glands, pancreas, and lymphatic system. Certain health problems have been linked to ferrets being neutered before sexual maturity was reached, and because of this some owners now choose to use implants instead of having the ferret neutered too early. Some owners even choose not to have their ferret neutered at all but use longer working implants instead. Certain colors of ferret may also carry a genetic defect known as Waardenburg syndrome.
Due to speculation on the possible effects of the photoperiod effect on the ferret's adrenal gland, some owners prefer to house their pets outdoors in sheds, and not indoors.
A common ailment which is fatal in ferrets is foot rot (cage rot). Foot rot is a form of fungal infection which attacks the feet and is sometimes found to affect the tail. It initially appears as a small, yellow, scab-like infection. If untreated, it can cover the feet. In worse cases, almost the entire body. Foot rot is normally caused by poor cage hygiene, ie. feces accumulation.
Adrenal disease, a growth of the adrenal glands that can be either hyperplasia or cancer, is most often diagnosed by signs like unusual hair loss, increased aggression, constant grooming of owner or other ferrets as well as themselves, difficulty urinating (caused by an enlarged prostate) or defecating, or agitation when urinating, and (in the case of females) an enlarged vulva. Signs of an enlarged prostate should be considered an emergency; even if the growth is benign, it can still cause a hormonal imbalance which can have devastating effects on the ferret's health.
Treatment options include surgery to excise the affected glands, melatonin implants, which treat the symptoms but not the disease itself, and/or hormone therapy. The causes of adrenal disease are as yet uncertain, but speculated triggers include unnatural light cycles, diets based around processed ferret foods, and prepubescent neutering. It has also been suggested that there may be a hereditary component to adrenal disease.
Adrenal disease is usually detected during the spring or fall, as it affects the hormones that make the fur grow. When affected ferrets shed their winter coat, the fur does not grow back. The hair loss pattern is usually very specific for adrenal disease. It begins at the base of the tail and then continues up the back. Ferrets treated for adrenal disease may suffer temporary but severe hair loss as their bodies recover.
Ferrets may suffer from insulinoma, a cancer of the pancreas. The growth of cancerous nodules on the lobes of the pancreas sometimes, but not always, leads to an increase in the production of insulin, which regulates the rate at which the ferret's body metabolizes blood glucose. Too much insulin will cause blood sugar to drop, resulting in lethargy, seizures, and ultimately death. Symptoms of an insulinoma attack include episodes of lethargy, drooling, pawing or foaming at the mouth, high pitched screams, staring "blankly" into space, and seizures.
Like adrenal cancer, the exact cause of insulinoma is unknown. It is speculated that the diets of domestic ferrets are too far removed from the natural diets of their polecat ancestors, and include too much sugar or simple carbohydrates.
Treatment for insulinoma may include surgical excision of the cancerous lobes, pharmaceutical treatment with steroids that suppress the production of insulin, supplemental changes in diet (most often poultry-based baby food), or a combination thereof. Unfortunately, the growth of the tumors cannot always be completely stopped, and the ferret will sometimes suffer a recurrence of symptoms. In an insulinoma attack, a temporary remedy to stabilize the ferret is any kind of a sugary syrup, such as corn syrup or honey.
Lymphoma/lymphosarcoma is the most common malignancy in ferrets. Ferret lymphosarcoma occurs in two forms -- juvenile lymphosarcoma, a fast-growing type that affects ferrets younger than two years, and adult lymphosarcoma, a slower growing form that affects ferrets four to seven years old.
In juvenile ferret lymphosarcoma, large, immature lymphocytes (lymphoblasts) rapidly invade the thymus or the organs of the abdominal cavity, particularly the liver and spleen. In adult ferret lymphosarcoma, the lymph nodes in the limbs and abdominal cavity become swollen early on due to invasion by small, mature lymphocytes. Invasion of organs, such as the liver, kidney, lungs, and spleen, occurs later on, and the disease may be far advanced before symptoms are noticeable.
As in humans, ferret lymphosarcoma can be treated surgically, with radiation therapy, chemotherapy or a combination thereof. The long-term prognosis is rarely bright, however, and this treatment is intended to improve quality of life with the disease.
Epizootic catarrhal enteritis (ECE)
ECE, a viral disease that first appeared in the northeastern US in 1994, is an inflammation of the mucous membranes in the intestine. The disease manifests itself as severe diarrhea (often of a bright green color), loss of appetite, and severe weight loss. The virus can be passed via fluids and indirectly between humans. Although it was often fatal when first discovered, ECE is less of a threat today, with the right supportive care, that usually includes hospitalization with intravenous fluids. The virus is especially threatening to older ferrets and requires immediate attention.
Aleutian disease virus (ADV)
Aleutian Disease Virus (ADV) is a parvovirus discovered among mink in the Aleutian Islands in the early 20th century. In ferrets, the virus affects the immune system (causing it to produce non-neutralizing antibodies) and many internal organs, particularly the kidneys. There is no cure or vaccine for the disease, and ferrets may carry the virus for months or years without any external symptoms. As a result, some ferret organizations and shelters recommend that owners test their pets for the virus regularly, separating them from other ferrets if they test positive.
Canine distemper Canine distemper (CD) is an extremely contagious virus that is considered always fatal. Being strict indoor pets does not necessarily protect ferrets, as owners may bring the virus home on their clothes or their shoes. The distemper virus is very short-lived in hot, dry weather, but may persist on hands or surfaces for much longer in cool, damp weather. The only protection against the virus is vaccination, but that is not without controversy as there have been reports, particularly from the USA, of ferrets going into anaphylactic shock after being vaccinated against CD. There is some anecdotal evidence that occurrence of a vaccine reaction is related to a low blood sugar level, and that feeding the ferret a sweet paste-type nutritional supplement shortly before the vaccination to raise the blood glucose has reduced the incidence of reactions. Some veterinarians routinely pre-treat with an antihistamine before the vaccination.
An adult ferret, or a kit past the age of eleven weeks, needs an initial series of two vaccinations, three to four weeks apart, followed by an annual booster. After that, antibody titer level can be tested to determine if protection is remaining adequate. Younger kits may have a residual "maternal immunity" from their mothers, preventing the first vaccination(s)from "taking". Hence a kit may receive vaccinations at six weeks and eight weeks, and still need their last two "shots" at eleven and fourteen weeks.
A ferret with partial immunity to distemper can be exposed to canine distemper and go through an incubation period of up to six weeks before showing symptoms, but an unvaccinated ferret will develop symptoms in just a few days. Symptoms can include runny nose, discharge from the eyes, fever (up to 107 degrees F.), and severe malaise, followed by development of changes in the skin including discoloration and thickening of the nose (a pink nose will develop an orange coloration), measles-like sores on the chin and belly, and thick crusting of the pads of the feet (hyperkeratosis). The discharge is highly contagious to other unvaccinated ferrets and canines. If the ferret survives the initial acute phase of the disease, they will die within a few weeks from a progressive and incurable neurological infection, progressing to severe epileptic seizures and death.
Influenza virus isolation using ferrets
Ferrets have served as a good experimental animal models in the study of influenza virus. Smith, Andrews, Laidlaw (1933) inoculated ferrets intra-nasally with human naso-pharyngeal washes, which produced a form of influenza that spread to other cage mates. The human influenza virus (Influenza type A) was transmitted from an infected ferret to a junior investigator, from whom it was subsequently re-isolated.
Ferrets with a white stripe on their face or a fully white head, primarily blazes, badgers, and pandas, almost certainly carry a congenital defect which shares some similarities to Waardenburg syndrome. This causes, among other things, a cranial deformation in the womb which broadens the skull, white face markings, and also partial or total deafness. It is estimated as many as 75% of ferrets with these Waardenburg-like colorings are deaf. Beyond that, the cranial deformation also causes a higher instance of stillborn ferret kits, and occasionally cleft palates. Because of this, many breeders will not breed Waardenburg-patterned ferrets.
Hairballs can occur in ferrets, but are not readily expelled by vomiting like the way cats deal with them. One or more hairballs in a ferret may lead to loss of apetite and subsequent weight loss. A hairball may enter the intestine and cause a life-threatening obstruction. Ferrets typically replace their coats twice a year, and at that time require brushing to remove loose hairs before they can be injested, and possibly administration of a hairball remedy as a preventative. Artificial lighting or administration of certain medications may alter the normal spring and fall seasonal coat changes in the ferret.
Dental health is a very important part of any ferret's health, and should not be neglected.
Ferrets have four types of teeth (the number includes maxillary(upper) and mandibular(lower) teeth)
- Twelve small teeth (only a couple of millimeters) located between the canines in the front of the mouth. These are known as the incisors and are used for grooming.
- Four Canines used for killing prey.
- Twelve Premolar teeth that the ferret uses to chew food, and are located at the sides of the mouth, directly behind the canines. The ferret being a carnivore uses these teeth to cut flesh, using them as scissors, cutting the meat into digestible chunks.
- Six Molars (Two on top and four on the bottom) at the far back of the mouth are used to crush food.
Dental calculus (tartar) is a hard substance formed on the teeth from the mineralization of plaque.
Dental tartar primarily comes from wet food which get stuck to the teeth for extended periods of time. The best way to avoid tartar is to feed the ferret raw meat, bones and preferably whole prey. The biomechanics of consuming meat and bones will keep the teeth clean.
Tartar, left to itself may lead to gingivitis which in turn can lead to a dental abscess, bone loss, infections which may spread bacteria through the bloodstream to internal organs and lead to death if not treated.
Tartar can be removed either mechanical or by ultrasound at a veterinarian (this usually involves anesthesia), a small toothbrush can also be used as a preventive measure if one is unable to feed the animal with raw meat.
Prevention is better than treatment, and tartar can be prevented by feeding raw food or giving specially made gelatin treats for ferrets.
Dental abrasion or tooth wear is common in ferrets, and is caused by mechanical wear of the teeth.
Eating manufactured dry food (kibble) will erode (due to the hard and extremely dry kibble) the carnassial teeth of the ferret, the wear from the eating kibble can become significant with old age (after three to five years). If teeth are overly ground down, a ferret cannot use them as scissors to eat raw meat. Tooth erosion eventually affects a ferret's ability to eat solid food.
Dental abrasion can also be caused by excessive chewing on fabrics or toys, and cage biting. If the ferret engages in these activities a lot, it might be a sign of boredom, and more stimulating activities (such as play) should rectify the situation.
Terminology and coloring
Male intact ferrets are called hobs; female intact ferrets are jills. A spayed female is a sprite, a neutered male is a gib, and a vasectomised male is known as a hoblet. Ferrets under one year old are known as kits. A group of ferrets is known as a business, or historically as a fesnyng .
Ferrets are various colors and patterns. Color refers to the color of the ferret's guard hairs, undercoat, eyes, and nose. Pattern refers to the concentration and distribution of color on the body, mask, and nose, as well as white markings on the head or feet when present. The colors and patterns recognized by the American Ferret Association are as follows:
White ferrets were favored in the Middle Ages for the ease in seeing them in thick undergrowth. Leonardo da Vinci's painting Lady with an Ermine is likely mislabeled; the animal is probably a ferret, not a stoat, for which "ermine" is an alternative name (the latter strictly applying only to the animal in its white winter coat). Similarly, the Ermine portrait of Queen Elizabeth the First shows her with her pet ferret, who has been decorated with painted-on heraldic ermine spots.
"The Ferreter's Tapestry" is a fifteenth-century tapestry from Burgundy, France now part of the Burrell Collection housed in the Glasgow Museum and Art Galleries. It shows a group of peasants hunting rabbits with nets and white ferrets. This image was reproduced in Renaissance Dress In Italy 1400-1500, by Jacqueline Herald, Bell & Hyman — ISBN 0-391-02362-4
Gaston Phoebus' Book Of The Hunt was written in approximately 1389 to explain how to hunt different kinds of animals, including how to use ferrets to hunt rabbits. Illustrations show how multicolored ferrets that are fitted with muzzles were used to chase rabbits out of their warrens and into waiting nets.
Regulation on ferrets as pets
- Australia - It is illegal to keep ferrets as pets in Queensland or the Northern Territory; in the ACT and Victoria a licence is required.
- Brazil - They are only allowed if they are given a microchip identification tag and sterilized.
- Iceland - Selling, distributing, breeding and keeping ferrets is illegal in Iceland.
- New Zealand - It has been illegal to sell, distribute or breed ferrets in New Zealand since 2002.
- Portugal - It is illegal to keep ferrets as pets in Portugal. Ferrets can only be used for hunting purposes and can only be kept with a government permit.
- United States - Ferrets were once banned in many US states, but most of these laws were rescinded in the 1980s and 90s as they became popular pets. Ferrets are still illegal in California under Fish and Game Code Section 2118 and the California Code of Regulations. Additionally, "Ferrets are strictly prohibited as pets under Hawaii law because they are potential carriers of the rabies virus"; the territory of Puerto Rico has a similar law. Ferrets are restricted by individual cities, such as, Washington, DC and New York City. They are also prohibited on many military bases. A permit to own a ferret is needed in other areas, including Rhode Island. Illinois and Georgia do not require a permit to merely possess a ferret, but a permit is required to breed ferrets. It was once illegal to own ferrets in Dallas, Texas, but the current Dallas City Code for Animals includes regulations for the vaccination of ferrets. Pet ferrets are legal in Wisconsin, but an import permit from the state department of agriculture is required to bring one into the state.
- Japan - It is legal to keep ferrets as pets in Japan. In Hokkaido prefecture, ferrets must be registered with local government. In other prefectures, no restrictions apply.
Ferrets cannot be imported into Australia. A report drafted in August 2000 seems to be the only effort made to date to change the situation.
Ferrets brought from anywhere except the US require a Permit to Import from the Canadian Food Inspection Agency Animal Health Office. Ferrets from the US require only a vaccination certificate signed by a veterinarian. Ferrets under three months old are not subject to any restrictions for importation.
As of July 2004, dogs, cats, and ferrets can travel freely within the European Union under the PETS travel scheme. To cross a border within the EU, ferrets require at minimum an EU PETS passport and an identification microchip (though some countries will accept a tattoo instead). Vaccinations are required; most countries require a rabies vaccine, and some require a distemper vaccine and treatment for ticks and fleas 24 to 48 hours before entry. PETS travel information is available from any EU veterinarian or on government websites.
Although previously pet ferrets were allowed to be brought into Japan, that is no longer the case. Individual pet ferrets cannot be brought into Japan without proper documents. However, licensed breeders such as Canadian Farms, PVF and Marshall's have a special agreement which still allows the import of ferrets from those companies.
The UK accepts ferrets under the EU's PETS travel scheme. Ferrets must be microchipped, vaccinated against rabies, and documented. They must be treated for ticks and tapeworms 24 to 48 hours before entry. They must also arrive via an authorized route. Ferrets arriving from outside the EU may be subject to a six-month quarantine.