I was slowly putting the finishing slanderous accusations in the last parts of the pet food label series, and gave the lot of them to a good friend and fellow critical thinker for comment. I am glad I did, for two reasons. One, in my drug induced state, I made a serious factual mistake by failing to insert an "im" in front of a word (but I won't tell you which word), and two, it was pointed out to me that I was assuming people understood basic comparative nutrition. It was suggested that I discuss a tiny bit of the philosophy *I* use, since it is that background I draw upon to write these posts. 1. Animals evolved eating specific foods, which over long periods of time resulted in morphological and physiological changes which better adapt them to that diet. In ferrets, there have been changes in the dentition, gastrointestinal tract, digestive enzymes, and metabolic pathways which reflect the fact. Ferrets are obligate (or strict, or primary) carnivores. An obligate carnivore is not just an animal which eats 95% or more of animal food, BUT is also REQUIRED to eat animal food because they cannot get essential nutrients from plants. A ferret CANNOT be a vegan. There are at least two amino acids (maybe three) that have been proven to be essential in ferrets, and neither are manufactured by plants. The ferret lacks ANY type of a caecum, and there is not even a (macro) visual difference between the small and large intestines. Digestion time is extremely fast (the intestinal transit time is 3-5 hr.) which makes plant digestion difficult or impossible. Also, the ferret lacks many enzymes required to digest plant food. The ferret's teeth are heavily modified to render meat into gulpable pieces; they do have a molar, but it is extremely small--in the lower jaw it is about the size of the flat end of a straight pin. ALL these modifications (and more) are proof of the extreme dietary modifications bred into ferrets (via polecats) over millions of generations. 2. When the adaptations to diet have reached stasis (that is, there are no external factors pressuring change), then the diet consumed by the animal is the best diet possible. The polecat-weasel family is very stable; which new species erupt and old ones go extinct, the basic size and shape of the group has remained extremely stable for about 10-20 million years. While a scientist cannot reach into a bag and pull out a 10 million year old weasel, we can assume the diets of the ancestors were about the same as their modern offspring. How? Since body and tooth shape is strongly influenced by hunting pressure, and no significant changes have occurred in either, we can conclude that while there may have been changes in the species eaten, the TYPES of animals have remained consistent. This suggests ferrets (via polecats, via weasels, via protoweasels, via general mustelid ancestor) have evolved dietary modifications over a long time period, and those changes have become integral to the health of the ferret. 3. Domestication is a short term, human mediated process. An animal can be technically domesticated within 7 generations, give or take a few, with VERY few external and NO internal changes. Domestication results in changes which benefit HUMAN desires, so those traits which are most impacted are generally those of behavior (more friendly towards humans and/or cohorts), muscle yields (or egg or milk), health, reproduction, and fur quality. Domestication works best on those traits which are inherently adaptable; that is, which have a wide range of values. It works poorly on those traits which have little or minute variation. In other words, in the ferret, domestication can change behavior rapidly, because behavior is highly variable. Mammalian physiology, while certainly having variation, does not have such a wide degree of latitude because physiological processes are governed by biochemical laws. Physiological functions are therefore the hardest to change, and there is NO evidence they have changed since ferrets have been domesticated. 4. It is a reasonable assumption to conclude the ferret's optimal diet would be close to what they evolved eating; that is, small rodents, amphibians, rabbits, small birds, carrion, worms, insects and the rare fruit. Any diet which is structurally similar in terms of nutrients, bulk, energy density, and components of elimination SHOULD result in optimal results. In other words, to eliminate the effect of diet on the health and condition of the ferret, they should fed a diet as close as possible to the evolutionary diet, in amounts which eliminate limiting factors. 5. Pet food is NOT necessarily the same as an evolutionary diet. It is a dietary substitute which approximates the nutritional requirements of the ferret, which are, at this point, unproved. Since there are no published reports of the ferret's nutritional needs, BY DEFINITION, it is not PROVED that a commercial food can adequately replace the evolutionary diet, and claims of such must be viewed with skepticism, especially with the introduction of food classes not typically consumed. In other words, it is up to the pet food people to PROVE carbohydrates are benign, and us to question. Bob C and 16 Mo' Theoretical Mustelid [Posted in FML issue 3052]