Holistic Ferret Care
By Christie Keith

Although ferrets are the third most popular pet in America, when it comes to the popularity of natural diet and health care, they are second-class citizens to cats and dogs. And yet, ferrets, even more so than cats, are true carnivores who suffer severe ill effects from inappropriate diet and care. How can you feed and care for your ferret to maximize health and lifespan, and minimize problems?

The Evolutionary Model for Diet

Whether talking about dogs, cats, humans, horses, or any other animal, the first place people look when trying to design a natural diet is the evolutionary diet of the species. What is the true natural diet of the ferret’s wild ancestor?

The ferret is considered a domesticated version of the Western or Eastern European polecat. Domesticated ferrets can interbreed and produce fertile offspring with either type of polecat. According to exotic animal veterinarian Susan Brown, DVM, “It is interesting to note that if wild polecat babies are taken from their mother prior to opening their eyes and then raised by a human, they will imprint on the human and become relatively tame. They can remain tame if there is continued contact with humans. In contrast, mink and weasels that are hand-reared may become tame for a short period, but usually revert to a fearful wild state at maturity. This docile behavior upon being hand-raised may be a key to why ferrets could be domesticated in the first place.”

So, what do polecats eat? They eat rats, mice, rabbits, amphibians such as frogs, voles, invertebrates, snakes, and fish. Nowhere on that list will you find corn, wheat, rice, soy, or any other form of grain, the mainstay of kibbled commercial ferret food. Like cats and much more so than dogs, whole prey animals make up virtually the entire diet of the polecat.

Whole prey animals such as mice, rats, small birds, and rabbits are available from a variety of sources to feed to ferrets. Some companies market these products as reptile food, while others are catering to cat and dog owners. All are good sources of whole prey animals for your ferret.

Compromises

Feeding whole prey animals to pets is very difficult for many of us. Ferrets are often owned by people who also keep their natural prey as pets. It’s very hard to feed rats and rabbits to your ferrets, and then look your pet rat or rabbit in the eye afterward. Raw commercial diets containing very little or no vegetable material are available, in which the whole prey animal is already ground, bones and all. You can also use meat sources that might be easier for you as a pet owner to “stomach,” such as chicken, lamb, or beef. However, be sure that all these diets provide the full spectrum of nutrients your ferret needs, as would be found in a whole prey diet. Dog and cat owners who already feed raw meat diets to their pets probably will not find this as much of an issue.

Nutrient availability must be considered as well; cats fed a diet of whole ground rabbit became taurine-deficient after a period of time, even though fresh rabbit contains sufficient taurine levels for felines. Storage and preparation of prey diets (and cooked, processed diets as well!) may degrade or render unavailable some essential nutrients, so a high quality vitamin and mineral supplement, supplementation of amino acids such as taurine and carnitine, and appropriate supplementation of essential fatty acids will provide a margin for error in diet composition. This is less crucial in ferrets fed fresh whole prey diets, and Dr. Brown actually says that such diets do not require supplementation.

Consequences

What happens when the diet of the polecat in the wild is ignored as a source of information about domesticated ferret diet? In other words, what harm is it going to do to the ferret if you feed him an inappropriate diet?

Today, there is an epidemic of a disease known as insulinoma among ferrets in the United States. This is a cancer of the beta cells of the pancreas. Blood sugar metabolism in ferrets appears to be extremely sensitive to dietary disruption, and diets high in carbohydrate (such as kibbles) cause the pancreas to produce higher levels of insulin in response to high levels of glucose in the bloodstream. According to Dr. Brown, “If the high carbohydrate diet continues, the result may be a complete burnout of the cells, which is what happens when a pet or a person develops diet-induced diabetes. However, another possibility is that instead of the cells burning out, they go from hypertrophy to neoplasia (cancer). Neoplasia is an abnormal growth of cells and can be preceded by a hyperplastic condition. I would like to stress that this exact mechanism has not been scientifically proven in ferrets to date, but the scenario is entirely within the realm of possibility. It has been disturbing to note that over the years in countries where ferrets were fed a raw carnivore-type diet insulinoma was a rare occurrence but now in these same countries where processed diets are becoming popular, cases of insulinoma are on the rise.”

All of the body’s hormone-producing systems are part of a complex and interconnected system known as the endocrine system. When insulin metabolism is disrupted, it impacts all other hormone systems, including the adrenal glands, which produce the hormone cortisol. Ferrets are also prone to an incredibly high level of adrenal disease, including cancer and both hypo- and hyper-adrenocorticism (Addisons and Cushings).

It is also intriguing to note that British and European veterinarians report that ferrets in their practices rarely suffer from the adrenal and pancreatic disorders and cancers that are so common in American ferrets. Raw meat diets are very common for ferrets in the UK and Europe, and very uncommon in ferrets in the US.

The Evolutionary Model for Lifestyle

The polecat has a natural range of as much as 6000 acres, which means that a nice roomy cage and some lap time in front of the TV just aren’t going to cut it with your pet ferret. Polecats are extremely active animals, who love to swim and also to burrow, dig, and chew. They are natural tunnelers, building lairs where they live and store food. In addition to finding creative ways to provide your ferret with large amounts of exercise, you also need to find safe ways to satisfy her need to hide, to chew, to dig, and to burrow. Habitats, preferably including safe outdoor play areas such as ferret-proofed wire enclosures, should be constructed, and they should include pipes for ferrets to use as tunnels, and other hiding places. Cage time should be kept to a minimum, and you should be aware that many ferrets live entirely cage-free existences when their owners are able to provide ferret-proof living space for them. A cage is for our convenience rather than the ferret’s happiness, although it is preferable to leaving your ferret free to harm herself in an unsafe environment when unsupervised.

When the disparity between the average pet ferret lifestyle and the lifestyle of the wild polecat is considered, the epidemic of endocrine system problems in ferrets takes on a new light. It is well-known that both insulin and cortisol production in humans are impacted by exercise levels, and it would make sense that appropriate exercise would benefit the ferret endocrine system, possibly minimizing some of the effects of incorrect diet, or acting in concert with correct diet to benefit your ferret even more.

Stress also causes the adrenals to produce cortisol, which further disrupts the pancreas’ production of insulin. Ferrets are by nature secretive, shy, active, and nocturnal. High levels of noise, a lack of places to hide, not enough exercise, too much artificial light, and being encouraged to be active in daylight hours may all increase stress levels to a point where adrenal function is disturbed. Can you imagine being a secretive, lair-dwelling, nocturnal animal forced to live in a cage that has only one, or perhaps not even one, side that is against a wall? To suggest this might leave your ferret in a constant state of hypervigilance and adrenal exhaustion doesn’t seem too far-fetched.

When humans take predatory carnivores into our homes as companion animals, there is a tremendous burden on us to provide them with the diet and lifestyle they evolved on. To fail to do so will often lead to avoidable health problems, and heartbreak for anyone who really loves their pets. Don’t let the convenience of kibble and cages blind you to the true nature of your domesticated polecats, wolves, or cats; all are carnivores, all are hunters, and all need an active lifestyle and species-appropriate diet to reach their full potential.

More Resources

• Natural Ferret Care Resource Center (includes a weekly online chat)
• Rethinking the Ferret Diet by Susan Brown, DVM
• Natural Ferret Email List

Copyright 2004 by Christie Keith. All rights reserved.