Care of Ferrets
Ferrets (Mustela putorius furo) are carnivores in the family Mustelidae, and are related to weasels, mink, badgers, and otters. Male ferrets are called hobs, females are called jills, and babies are kits. Breeding age is reached between the ages of 4 and 8 months of age, although most ferrets produced for the pet trade are spayed or neutered (as well as de-scented) before reaching puberty. Gestation length averages 42 days with an average litter size of 8 to 10 kits. Weaning occurs at 6 to 8 weeks of age. Ferrets can be expected to live an average of 5-7 years in captivity.
Ferrets should be housed indoors as they do not tolerate heat very well. The enclosure should be large enough for the ferrets to roam and play. Be aware that ferrets are notorious for being excellent escape artists and their curiosity can get them into trouble. If allowed to roam free, they should be monitored at all times; some will allow a collar or harness with leash attached. Furnishings in the enclosure should include a soft, dark place to sleep (e.g. shirts, towels, fleece) and toys to play with (rubber cat and dog toys should be avoided). Hammocks, slings and shelves to climb can also be provided. Be aware that some ferrets insist on chewing cloth so sleep boxes may need to be fashioned out of cardboard or plastic containers. As for bathroom habits, some ferrets can be trained to use a litterbox.
The complete dietary requirements of domestic ferrets are still a matter of controversy. As obligate carnivores, fats and proteins are the main source of energy. Ferrets have a very short gastrointestinal (GI) tract and the intestinal flora (the organisms living in the GI tract) are very simple, unlike the flora of animals that eat more vegetation. It takes about 3 to 4 hours for food to go from one end to the other and thus the food eaten must be of very high quality because there is little time to digest and absorb it. Ferrets cannot digest fiber, as is found in some vegetable and fruit sources. If there is a significant amount of fiber in the diet it serves to lower the nutritional value of the food. The bottom line is that ferrets use fat for energy, not carbohydrates, and they need a highly digestible meat-based protein, not vegetable protein. Keep a high quality ferret food, such as Marshalls or 8-in-1, and fresh water available at all times. To prevent hairball formation, an oral laxative paste (Laxatone) can be given every 2 to 3 days and helps serve as a treat.
Annual examinations and vaccines are required to maintain health and to ensure that health problems are caught early when diagnostics and treatments can be more successful. All ferrets should be vaccinated against canine distemper virus and rabies virus. Allergic reactions to vaccines can occur but are treatable and can be prevented in the future with appropriate medications. Signs of a vaccine reaction include vomiting, diarrhea, salivation, and lethargy. Clients are encouraged to remain at the veterinary hospital for a minimum of 10 minutes after vaccine administration so that, in the event of a reaction, treatment can be given immediately.
Diseases of Ferrets
Fleas – Ferrets are susceptible to fleas, particularly if they are kept outdoors, but can also be infested if other pets in the house bring fleas inside. A successful flea control program has to include control of the parasite on the pet as well as the environment. Advantage and Frontline Plus can be used safely on ferrets to kill fleas. Don’t forget that ALL the pets in the household need to be taken into account when determining what products to use.
Influenza – Ferrets are highly susceptible to the human influenza virus or the “flu.” They do not get the common cold, which is caused by another set of viruses. Ferrets can get the flu from humans and humans can contract the flu from ferrets through contact with respiratory secretions. Adult ferrets develop a watery discharge from the eyes and nose, sneezing, coughing and a fluctuating fever. Occasionally they also develop diarrhea. They feel miserable for a few days but usually recover uneventfully without medications. Baby ferrets can be more severely affected, so avoid handling baby ferrets if you have the flu.
Epizootic Catarrhal Enteritis (ECE) – This is the name given to “green slime disease” that has affected ferrets, particularly in shelters, since 1993. The current theory is that this disease is caused by a coronavirus. Fortunately, most ferrets recover uneventfully from ECE; however, some ferrets, particularly older ones or those with other disease, can be severely affected. ECE spreads rapidly and ferrets exposed will exhibit signs of disease within 48 to 72 hours. The signs of illness initially can range from vomiting and a soft, green, mucous-coated stool to bloody diarrhea. Recovered ferrets and some unaffected ferrets may be carriers. Young ferrets usually recover from ECE rapidly, but older ferrets may lose significant body condition and continue wasting once the diarrhea is gone. Treatment depends on the severity of the illness and can include intestinal coating agents or antacids, anti-diarrheal drugs, antibiotics, injectable fluids and dietary changes.
Foreign bodies in the intestines or stomach – Ferrets, particularly under a year of age, love to eat foam and latex rubber, which can become lodged in the intestine or stomach. In addition, ferrets over one year of age can develop large masses of hair in the stomach, which also can cause an obstruction. All of these situations are dangerous and usually require surgery to remove the foreign material. Signs of a foreign body obstruction includes lethargy, extreme dehydration, vomiting (but they often don’t), lack of stools, painful abdomen, seizures and death.
Heartworm disease – Ferrets, like dogs and cats, are susceptible to infestation by the heartworm. Mosquitoes transmit the larvae of this parasite when they feed on a host. The adult worms live in the heart of the pet, and in a ferret, the heart is so small that the presence of even one or two worms could be fatal. Regular heartworm testing and medication is the key to preventing heartworm infection.
Dental disease – Dental infections and gingivitis occur commonly in ferrets and can be detected by oral examinations performed at each annual office visit. Ferrets should have their teeth professionally cleaned by a veterinarian to avoid tooth loss and painful periodontal disease.
Insulinoma – Tumors of the pancreas, called insulinomas, are relatively common in ferrets. These tumors secrete an excess of insulin, a hormone important in controlling blood sugar levels, and drop blood sugar to life-threateningly low levels. Signs include lethargy, salivation, periods of high energy followed by extreme listlessness, and sometimes seizures. Treatment varies depending on the age of the pet.
Hyperadrenocorticism/Adrenal Tumors – This disease is characterized by excess production of sex hormones and is typically the result of a tumor of one or both adrenal glands. It is estimated that 20% of all ferrets will develop this disease. Signs include itchy skin, hair loss (often beginning at the tail but extending along the back), weight loss, and a swollen vulva in females. Treatment is aimed at surgically removing the affected gland and having it analyzed for malignancy.
Skin tumors – As ferrets age they are more prone to develop lumps and bumps on their skin. Most of these lumps are neoplasms or tumors. Fortunately, the majority are benign, but it is best to have them removed because one cannot tell benign from malignant without a biopsy.
Urinary tract disease – Ferrets are susceptible to urinary tract infections and even bladder stones. The stones can become lodged in the urethra, obstructing the flow of urine, and can lead to fatal metabolic derangements. Signs include frequent attempts to urinate, straining to produce urine, and inability to pass urine. Ferrets are often lethargic and nauseated from toxins building up in the blood stream. Urinary tract obstruction is a medical emergency and often requires surgical correction.
Cardiomyopathy – Heart disease is not uncommon in ferrets and can occur at any age, although typical age of onset is >2 years. The walls of the heart become thickened reducing the ability of the heart to pump blood to the rest of the body. The signs of the disease are weakness, particularly after exercise, and an overall loss of energy. Ferrets usually don’t cough, but may have more rapid breathing. Diagnosis of the type of disease requires an ultrasound of the heart and sometimes an ECG (electrocardiogram). The prognosis for control of heart disease depends on the type of disease and its severity.
Lymphoma – Cancer of the lymphocytes (a type of white blood cell) can affect ferrets of any age and can be difficult to diagnose as symptoms are often non-specific. Chemotherapy has been used with success in some ferrets. The disease is fatal and usually aggressive.
*There are many more diseases to which ferrets are susceptible, too many to list here. Our goal is to provide a brief overview of the more commonly seen health problems and to give ferret owners information on symptoms of illness in ferrets.