Mr. XXXXXX has asked several excellent questions regarding the ferret's digestive anatomy and conversely how it effects the ferret's diet. Scientifically, a diet is that amount of nutrients in the proper quantity, quality and balance, feed to an animal in a palatable form, so that in a twenty-four hour period it will maintain or support its physiological state. Because ferrets have such a unique digestive system they are strictly limited as to what they can eat. As has been stated in many references, ferrets are obligate carnivores, meaning they must have a meat based diet daily. This is not a preference in selecting a food it is a must if the ferret is to live. Selecting a diet first and foremost must be on the basis of meat content. Many volumes have been written by numerous authors as well as myself in great detail on this subject. I will not cover selecting and evaluating a diet here. Regarding MR. XXXXXX's questions on the effect of the ferret's metabolic anatomy relative to what and how a ferret eats. A ferret has no ceacum. Dogs, cats, humans and most other animals have a ceacum. In those animal, the ceacums is located at the point where the small intestines widen to become the large intestines. This location is called the ileocolic junction. The ceacum itself is a blind pouch which functions to provide some digestion of the complex carbohydrates, and fiber. It contains nonpathogenic, symbiotic bacteria which secrete enzymes in the ceacum, which in turn digest the fiber and complex carbohydrates. The rabbit and horse have a disproportionate sized ceacum relative to their body size and most other animals, which allows them to eat large quantities of fibrous feedstuff such as hay and grass. Neither of these animals nor any other mammals secrete fiber digesting enzymes, these are only secreted by the bacteria in the ceacum. On the other hand, ruminants, such as cattle, sheep, goats, deer, etc., have a specialized digestive system, which allows them to digest high fiber diets such as grass and hay even more efficiently than the rabbit or horse. This is because the have a large paunch called a rumen which host to billions of symbiotic bacteria and single cell microorganism which in turn secrete fiber digesting enzymes that then break down the fiber in the food. Back to the ferret. The lack of a ceacum limits the ferret in eating fiber containing foods. From our research we found that fiber should not exceed 1.5% to optimize the digestibility of the whole diet. This is another reason why I recommend not feeding cat food or any other foods as the primary diet for the ferret if it contains more than 2% fiber. The second anatomical difference between ferrets and other carnivores, is the short large intestine or colon. Ferrets do have colons but an extremely short one. It is approximately 10 cm (3.94 inches) long. This proportionally is about 1/3 to 1/2 as long as a cats colon. The ferret's colon contains very little convolutions or folds which would aid in the water and nutrient recovery from digestion. The surface is almost smooth. There are very few bacteria in this area which is also contrary to most other animals which means the ferret cannot synthesize any B vitamins. These two anatomical differences plays a major role in what the ferret eats. The rate of passage for food from the time the ferret eats till it poops is about 3 to 4 hours. This further dictates that high quality animal protein must be the major portion of the diet. Probioticts or Prebiotics such as yogurt, lactobacillus, etc., or yucca, fructo- oligosaccharides (FOS) are therefore non effective in the healthy ferret because the intestinal track does not support bacterial growth as does those of other animals. This is a major reason why holistic foods are a rip-off and have no physiological benefits in ferrets. The ferret has a very specialized gut which has evolved eating meat as its primary protein and energy source. As Bob Church pointed out, the wild ancestors of the ferret, the polecat, also ate insects, eggs, and many types of small prey. There digestive system secrets very powerful proteolytic and lipolytic (protein and fat digesting) enzymes. They also secrete some lipase enzymes in the small intestine which digest the simple carbohydrates and sugars. However, their digestive system can be overwhelmed with simple carbohydrates such as sugar, dextrose, and fructose (fruit sugars) if feed foods or treats containing them. Fruits such as grapes, raisins, bananas, apples, cantaloupe contain both high levels of sugar as well as fiber. This is a double whammy for a ferret and should not be fed. A good ferret diet should contain at least 34 to 37% protein, 18 to 24% fat no more than 1.5% fiber and no more than 25% carbohydrates and no sugar. Of course the major protein sources should be from high quality chicken byproducts, meat, eggs and liver. Diets with gluten, soy or other complex vegetable proteins cannot be digested by the ferret and can even cause digestive problems. Regarding the effects of highly soluble carbohydrates such as sugar, or high carbohydrate diets (35% or higher), I am not aware of any studies which have established the long term effect of their feeding. Knowing their anatomy and reviewing the data from our own research, I do not believe it would be in their best interest for the long term health considerations of the ferret. Sincerely, DR Tom Willard [Posted in FML issue 3406]