As another, perhaps more topical example, 14 different people have asked me in the last three weeks if I was worried about the risks of ferrets developing protein-based stones from a high protein diet. My answer is no, no, no, no, absolutely no, I am not, never!! Ferrets are obligate, primary carnivores with unconditionally, unquestionably, categorically, and absolutely zero requirements for carbohydrate, which is a good thing because in nature they consume a diet between 40% and 60% protein, depending on the percentage of fat. In a very real sense, ferrets have been "genetically engineered," via natural selection, to consume a high protein diet. Ferrets couldn't survive as a predator if they developed stones from high protein diets, and if anyone suggests such a diet could cause stones in a normal, average ferret, demand scientific proof. This doesn't mean it can't or doesn't happen, but when it does, it means the individuals would normally die, and the bad genes exit the breeding pool. The process is called, "natural selection," and it has regulated the evolution of the weasel group of carnivores for millions of years, and in a seasonally breeding animal like the ferret, that means millions of generations. We know for a statistical fact that if this is indeed a problem in a small number of ferrets, it CANNOT be a trait in the general genetic pool! Why? Because Mendel has taught us that it would present in predictable ratios that are substantially better than the 1 or 2-million-to-1 chance of having the problem if ALL real, probable, possible, and imagined cases are proved to be correct. Think about it for a moment. There might be 5 million ferrets in the Western Hemisphere, and perhaps as many in the Eastern Hemisphere. How many ferrets have this problem? Even if there are only 1 million ferrets on the planet, the ratio would still be so skewed that the trait could not possibly be a genetic trait in the general population, and if anyone suggests it is, the burden of proof is on them to demonstrate otherwise. If this problem exists and is not actually lab error (there are more of those than you can ever imagine), it is usually either a spontaneous mutation, caused by something else in the diet or environment, or a defect in a particular breeding line, usually associated with inbreeding. One more comment is in order--a bit off the topic, but relating to the essential genetic character of the ferret (and to ward-off follow-up questions). Ferrets are domesticated polecats, and polecats are nothing more than a group of weasels that are larger than the rest. These animals eat different sizes of prey, but they all eat animals of one type or another to such an extent that it is nearly a universal fact that they exist on a diet that is 95% animal based, or greater. Less than 5% of the diet is non-animal, which includes fruits, nuts, prey digestive tract materials, and honey. There are more than 1000 scientific papers published in the last 150 years that detail the diet of this group of mustelids--including more than a dozen for the New Zealand feral ferret alone! I know; I have them in my files. The literature documenting the diet of this group of animals is so uniform and so extensive that ANY suggestion that any member of the weasel group requires a different diet places the BURDEN OF PROOF ON THE PERSON SUGGESTING THE DIFFERENCE! The burden of proof isn't on the people who suggest a natural diet is good; we already KNOW it is good because weasels scarfed it down for millions of years and they are still here, thriving, healthy, reproducing, and in some cases, expanding their range. Nor is there a requirement of the natural-food group to run scientific tests to prove their diet is a better one; natural selection has run experiments on that diet for several millions of years. We KNOW that diet works, so if anyone, especially someone with a vested interest in a pet food company, suggests some other diet is better, THEY have the burden of proof to show their claims are reliable. This means the natural diet is the STANDARD by which all other diets are judged, like it or not. Put simply, I dont have to prove the natural diet is good because weasels and polecats have lived successfully on it for millions of years, which means it has already proved it's nutritive value. Nor do I have to prove it is better than any other diet because, again, the burden of proof is the responsibility of the people who claim their diet is equal to or better than the one the ferrets evolved consuming. If the people making such claims don't understand they have the burden of proof, then I worry about the adequacy of their scientific methodology and if it hasn't biased their results or conclusions. This is an extremely important point, because there is a preponderance of evidence that a natural diet is better for animals of any species. The evidence is so overwhelming that it cannot be dismissed; if you want to claim something is better, or even it's equal, then you have to prove it. And I mean real, scientific proof, not commercial claims built on truncated, brief tests, but rather scientifically designed tests performed by an impartial committee that uses approved scientific methodology, and who will publish their findings. The bottom line about inbreeding for a desired trait is that statistically it generally results in the introduction of undesired traits simply because of the number and complexity of the remainder of the genome. If a bad or mutated gene is near the genes that code for your favored trait, it can link to it in a manner that you can't predict, and inbreeding will not just set the desired trait, but the bad ones as well. If you don't believe it, just check out the books on cat and dog genetic diseases. Ferrets, in contrast, have very few. On the other hand, each and every hamster you see in the pet shops around the world had their beginning in 1930 with a male and two females surviving from a single adult female and litter of 8 removed from the wild. There must have been a substantial amount of inbreeding necessary to produce the millions of hamsters that run through little plastic tunnels today, so it can be done. I don't know enough about hamsters and their genetic problems to feel comfortable about posting about them, so perhaps someone with more knowledge in the manner can respond in more detail. At a superficial level, it appears inbreeding hasn't caused really significant problems in hamsters, but I admit I could be mistaken, and if so, I hope the statement is corrected. Nonetheless, even if true, my opinion is that the risks of problems from inbreeding vastly outweigh the advantages, so I don't recommend it. Bob C [log in to unmask] It was the White Rabbit, trotting slowly back again, and looking anxiously about as it went, as if it had lost something; and she heard it muttering to itself, "The Duchess! The Duchess! Oh my dear paws! Oh my fur and whiskers! She'll get me executed, as sure as ferrets are ferrets! Where can I have dropped them, I wonder?" --Lewis Carroll 1866 Alice's Adventures in Wonderland. [Posted in FML issue 4786]