Domestication is a phenomenon governed by the rules of economics, especially when it comes to diet. Humans have ALWAYS substituted foods of lesser economic value than those normally consumed by domesticated animals, however that value is determined at the time (in the case of herbivores, herbivorous competition is usually also eliminated, such as the destruction of the bison for cattle). The problem with ferrets is that they have always eaten meat, so they were always economically a borderline case because of their dietary requirements. Ferrets, after 2500 years of domestication, rarely form feral colonies, yet feral cats exist everywhere. This is a clue to the popularity of cats and why they supplanted ferrets so easily after centuries of domestication and cultural acceptance. Even though both ferrets and cats ate economically important meat, cats were able to supplement their diet with food distained by people (rats, mice). Ferrets ate the same foods people desired (hamsters, rabbits), so remained in economic competition with humans. You can track ferret popularity by looking at published descriptions of their diet. When eating an economically expensive diet, ferrets were never very popular. As dietary substitutions became economically viable, ferrets increased in popularity. When kibbled pet foods became available and ferrets no longer competed with people for food, ferrets became popular pets. It is simple economics, but it illustrates an extremely important aspect of ferret ownership: pet popularity is highly correlated to cost of upkeep (but shelters already knew that). The reason the effect of an Ad Libitum diet is of such vast importance to ferrets and their owners is not just the issues of health and longevity. It isn't just the cost and convenience of feeding the furry little monkeys. It is also the economics of sick ferret abandonment and sheltering. You may not like it, you may think it is unethical or even immoral, but the fact is, when animals become ill many of them are discarded (killed or given away). This is probably the number one problem faced by shelters: overcoming the economic problems faced by the constant influx of ferrets requiring extensive veterinary care. There are only three real possibilities: an Ad Libitum diet causes health problems and shortens lives, it does not, or some degree of health problems in between the extremes. If the Ad Libitum diet has ZERO negative effects on ferrets, it would be a discovery of great importance: ferrets would be the first species exempt from what is considered to be a phenomenon that is considered phylogenetically independent. But if an Ad Libitum diet has ANY impact on the health of ferrets, then there is an ethical and moral imperative to discover those problems and attempt to correct them. It can help ferrets live longer, healthier lives, may reduce veterinary costs, and may help slow the influx of sick ferrets into our shelters. Bob C [Posted in FML issue 3980]