Biology

The ferret (Mustela putorius furo) is a domestic pet. It is not a wild animal, and is a close relative of weasels, minks, skunks, otters, and badgers. There are two varieties of ferrets, based on coloration.  Fitch ferrets (the most popular) are buff colored, with black masks, feet and tails.  Albino ferrets are white with pink eyes.  The female ferret is called a jill, while the male is called a hob.  Babies are called kits.

The gestation period of ferrets is 42-44 days (average 42 days).  The average litter size is 8 (range, 2-17).  Kits are born deaf, with their eyes closed.  Their eyes open and begin to hear between 3-5 weeks of age. Their deciduous (temporary) teeth begin to erupt at 2 weeks of age, at which time they begin to eat solid food.  Kits are generally weaned onto commercial kitten chow at 4-8 weeks of age.  Kits reach their adult weight at 4 months of age.  Males are typically twice the size of females, but both sexes undergo periodic weight fluctuations.  It is not uncommon for the average ferret to add 30-40% if its body weight in fat deposited beneath the skin in the fall, and lose this fat the following spring.  The average life span of ferrets is 7-10 years.  

The pet Ferret

Ferrets make wonderful pets because of their engaging personalities, playful activity and fastidious nature. They are never boring and can entertain you for hours. They enjoy people's company and will follow their owner. Ferrets have somewhat strong odor, which you have to live with. 

Husbandry

Ferrets can be easily trained to use the litter box because they tend to habitually urinate and defecate in the same places.  Provide a low-sided litter box for easy entry and exit.

Ferrets get along with other ferrets, dogs and cats. They are naturally inquisitive and can squeeze through very small places. It is important to “ferret-proof” your house before bringing your pet home. Make sure that all windows that may have been opened have secure screens. Check the openings around plumbing, heating and air condition ducts or pipes. Ferrets are so small and silent that you will usually not hear them approach.  They frequently get in dangerous situations (such as sneaking into the drier or end up in the washing machine with clothes they were sleeping under). Ferrets like to chew on soft rubber (Erasers, toys, tennis shoes) and can swallow pieces that might obstruct their intestines.    

Commercial dry kitten food or ferret food is used for ferrets. They usually do not require vitamin/mineral supplement. Fresh, clean water should be available at all times. 

Ferrets do not require large space and a relatively small cage will satisfy them. Newspaper or wood shavings can be used on the bottom of the enclosure.  Places a cloth or a towel in the cage as ferrets like tunneling and sleep under towels. 

Nails grow fast and should be trimmed periodically.

Common health problems

Canine Distemper 

Ferrets are highly susceptible to canine distemper. The initial signs of the disease include anorexia and a thick mucus and pussy discharge from the eyes and nostrils. A rash commonly appears under the chin and in the groin area. The footpads become greatly thickened.  This disease is fatal. The disease can be prevented by vaccination, which should start at 6-8 weeks of age. Yearly boosters are recommended thereafter. 

Adrenal gland disease

This is a common disease in ferrets, which consists in adrenal gland tumor and hormone hypersecretion. Signs include generalized hair loss, pruritus and vulvar enlargement. The treatment is surgical removal of the tumor.

Posterior paresis

Rare leg weakness and immobility is common in sick ferrets and represent non specific general weakness.

Green feces disease 

This is a serious and fatal disease characterized by green or black diarrhea, vomiting and progressive wasting. It is more common in young stressed ferrets and is caused by a bacteria related stomach ulcer. Antibiotic treatment is necessary and in hospital intensive care is often needed. 

Dental disease

Dental disease is common in ferrets. Teeth and gum disease is more common in older ferrets. Fractured teeth can be seen at any age.

Intestinal obstruction

Young ferrets are prone to ingesting rubber or plastic objects that cause intestinal obstruction. Signs include lethargy, anorexia and diarrhea. The condition requires surgery.

Heat cycle related anemia

Unspayed female ferrets in sustained sexual heat may develop bone marrow suppression and a consequent fatal anemia. The vast majority of ferrets is sexually altered and is not in danger.

Rabies 

Ferrets are susceptible to rabies and capable of transmitting the virus. Vaccination should be done on a yearly basis. 

Lymphoma 

Lymphoma (cancer of the blood cells) is a fatal disease characterized by anorexia, weight loss, lethargy and palpable tumors. Internal organs, lymph nodes and intestines are commonly involved. The disease can affect ferrets at any age and is incurable.

Influenza 

Ferrets are susceptible to infections with several strains of human influenza (“flu”) virus. They can contract the disease from the owner. Signs of illness include listlessness, fever, lack of appetite, sneezing, nasal discharge, and other upper respiratory signs. Ferrets usually recover from influenza within several days.  Bacterial infections may complicate the viral infection. 

Parasites 

Most of the external parasites of domestic dogs and cats (flea, mange mites, ear mites, ring worms etc) can cause disease in ferrets. Protozoan parasites (Giardia, Toxoplasma, Coccidia) can cause internal disease among ferrets.  Periodic fecal (stool) examinations should be performed by your veterinarian to check for such parasites. 

Heartworm Disease

Ferrets are susceptible to heartworm disease, a mosquito-transmitted illness seen primarily in dogs. Ferrets housed outdoors are at greater risk. 

Urinary Stones 

Urinary stones, either within the bladder or urethra, may cause serious problems in ferrets. Signs of urinary stones include blood in the urine, inability to urinate, a swollen and painful abdomen, vomiting, listlessness and no appetite.  Surgery is usually necessary. 

Cardiomyopathy

Cardiomyopathy is a disease of the heart muscle, which result in heart failure. The cause for this condition is unknown. Signs include inappetence, fatigue, and increased periods of sleep, intolerance to exercise, fainting and shortness of breath.

Insulinoma 

Insulin-secreting tumors are common cause persistent low blood sugar levels. Signs of the disease include weakness, depression, fainting spells, changes in behavior and convulsions.

Cataract

Cataracts are seen in ferrets (young and old).  Their significance and genetic predisposition are not fully understood.     

Veterinary care

A thorough initial examination is necessary for newly acquired ferrets. The veterinarian will start vaccinations for Rabies and distemper and discuss specific issues of husbandry regarding your ferret. A stool examination should also be done.

Ferrets should have a yearly physical examination and vaccinations. Ferrets older then three years should be seen twice a year and also have x-rays and a blood test once a year.