These facts DO answer the question. It is not so much what the ferret is eating as much as the mechanical characteristics of the food. For a polecat to survive, they have to catch prey, kill it, transport it, tear it open, shear through tendon and bone, and cut off chunks that can be swallowed. The teeth are constantly being abraded against fur, skin, muscle tissue, bone, tendons, and ligaments. This constant abrasion scours the teeth, rubbing off the dental plaque that calcifies into calculus. The scouring action also polishes teeth, gently smoothing out imperfections where plaque can accumulate and mineralize. It is not the food; it is the mechanics of eating. In contrast, pet ferrets that eat kibble have NO method for cleaning the teeth of plaque. Kibble is often marketed as an aid to dental calculus reduction, but in truth, it fails miserably at the job. The crunchy nature of the material supposedly cleans the teeth of plaque, but it only cleans the part of the tooth that comes into contact with it at the time of consumption the wear facets of the crowns. In a dog, having wide molars and a thick carnassial, tartar reducing kibble helps some (reduces but does not prevent), but ferrets have minimal molariform tooth surfaces, and the cheek teeth are thin and blade like. The only significant parts of the teeth kibble comes into contact with in ferrets are the wear facets. That is why ferrets on a kibble diet have huge accumulations of dental calculus on their teeth. A kibble diet will not help; at least any kibble currently on the market. Note that 2.3% of feral New Zealand ferrets had dental calculus. I'm not convinced these were true feral New Zealand ferrets. This number may reflect lost or abandoned pet ferrets what were caught in traps designed to catch feral animals. If that is the case, it might be possible for New Zealanders to check the cleanliness of teeth of captured or killed ferrets to ascertain the origin of a ferret captured in the wild; if the teeth have significant amounts of dental calculus, it was probably a pet. The same may be true in the United States where wildlife officials have a bad habit of claiming lost or abandoned ferrets are feral . Remember that 99.0% off all teeth having dental calculus came from pet ferrets. Why are ferrets so susceptible to dental plaque and calculus? There are no published studies that can answer that question (many document the phenomenon, but none explain it), but I have a hypothesis that might provide an answer. Ferrets are descendants of wild polecats, and polecats have been prowling the Earth for millions of years. During that time, they evolved into primary, obligate carnivores. That is to say they primarily eat animals, they are obligated to do so to obtain essential nutrients, and they have a digestive mechanics and physiology adapted to such a diet. All polecats share this trait, and polecats have undergone little change in the last 2 to 5 million years. To put that period into perspective, realize humans evolved within that time frame. I suspect that during that long period of primary carnivory, the polecat lost some of those mechanisms that help to keep the mouth clean of dental calculus found in other species. Such traits are energy expensive and since the polecat was consuming a diet that mechanically cleaned the teeth anyway, there would be little need to conserve the traits. Simplistically, it is possible polecats lost some of the mechanisms that help prevent the formation of dental calculus simply because they were consuming a diet that came packaged in toothbrush form. Mind you, this is an untested hypothesis, but it makes sense. So, what can be done to prevent dental plaque and calculus? The only way diet can be used to prevent it is to place the ferret on the same diet as a polecat; that is, whole animal bodies. There is no way kibble can help and just eating bone alone, even with the occasional mouse, doesn't do the job although it does help somewhat. The only real solution is mechanical cleaning, mimicking the job done by the fur and tissue in animal bodies. That means you have to brush the ferret's teeth and periodically you have to have the teeth professionally cleaned. That IS the bottom line; the only diet that can keep the ferret's teeth clean is consistent meals of whole animal bodies, and by consistent, I mean daily. I cannot do that, the vast majority of ferret owners will not do that, and current pet food marketing cannot meet the demand. That means the ONLY solution is tooth brushing and periodic professional cleaning. There are some products that can help. It has been reported that allowing a ferret access to Cheweasels helps to keep the teeth clean. I am currently testing that claim with some of my ferrets that decline to consume frozen mice. Totally Ferret has recently marketed a dental cleansing swab that may help, but I haven't been able to get enough of the product for a comprehensive test. Allowing the ferret to chew off the soft ends of bones help, as does giving them access to BOILED pig's ears (if not boiled until soft, the dehydrated cartilage doesn't have time to completely rehydrate in the ferret's stomach, and can potentially cause intestinal blockages). Aside from that, the only thing I can say is a whole mouse per day helps keeps the dentist away. As for toothbrushes, well, try to find one that easily fits into a ferret's mouth. I found the big boys can accommodate brushes designed for cats, but they gag the poor little girls. I have modified an infant's toothbrush by trimming down the bristles, and it works well enough for my girls. For some of my ferrets, I use 6 in. swabs to rub the teeth with dentifrice. My ferrets seem to tolerate cat toothpaste, but all seem to like the toothpaste for toddlers better, if you can define the occasional gag as tolerates better (note: infant toothpaste can be safely swallowed by ferrets). None of my ferrets like their teeth being brushed, so I just get a good scruff on them and start brushing. Some will fight, some will do the spin trick, some refuse to open their mouths, but most will give up trying to escape and just chew on the toothbrush while you struggle to polish their pearly whites. It isn't easy, but it HAS to be done! In the next installment, I will discuss periodontal disease in ferrets. Bob C Questions?: [log in to unmask] Communications? [log in to unmask] [Posted in FML issue 4517]