>What I am curious about, for all people who have had lots of ferrets or >shelters, is were the ferrets who lived to an old age 8+ thin? It would >be interesting to take a poll. One problem with just going from thinness is a problem that has also been encountered more than once in relation to the human studies on caloric restriction: that there is a lot more going on with thinness than just the calories taken in. For humans one of the most major problems is that higher caloric consumption and sarcopenia have strong overlaps. That can also happen with ferrets. Sarcopenia is a condition in which there is too little muscle mass from too little exercise. There is a spiral there because low levels of exercise cause fat increase while fat increase also often further reduces exercise. Low levels of muscle mass have already been linked to multiple health problems, from some malignancies through a pile of other things and on to increased injury rates due to reduced balance (BTW, there is some neat new work on a different approach to balance loss which will interest some folks here with medical problems or elderly family members: http://www.nytimes.com/2002/11/14/technology/circuits/14next.html .). High activity rates are also good for mental stimulation and can add to enjoyment of life for ferrets that way. High activity rates and good muscle mass keep ferrets and humans thin. Obviously, it is hard to know off-hand when seeing a thin ferret or person if the individual eats less, is more physically active, or both. It may turn out that both can have positive effects, but tweezing the two apart among humans is a very hard task which is not complete at this time from what i have read, and the same difficulty would exist when presented with thin ferrets. Surveying thin ferrets would not separate caloric intake from muscle mass and could give credit for benefits of an active lifestyle to diet incorrectly. It also easily might not work to then say, "Well, we'll look only at thin ones who have lousy muscle mass." because thin ones with lousy muscle mass are more likely to be ill, so those illnesses would skew the survey in the opposite direction and make caloric restriction likely look a degree of bad which also isn't likely to be the reality *when nutrients and comfort are carefully taken into account and the diet is suited to the individual's specific needs*. This is a question which extends beyond what an annotated bibliography can answer; real research is needed and until that exists I do think that folks are best off discussing it with their treating vets and going by what these independent, health-expert judges choose. I do not consider that to be an insulting opinion or a condescending approach; it's the way I handle such questions myself. I have 20 years of ferret background and a related educational background but I am not a vet and knowing my limitations is good for the health of my ferrets. Sharon quoted: >"Many studies have shown that aminals placed on severe calorie-restricted >diets throughout adulthood live 30% to 40% longer than animals kept on >regular diets. The animals in these studies also show fewer signs of >aging and have fewer chronic medical problems, including cancer." > >Of course, they don't recommend this for very old or ill animals (or >humans). Yes, there have been studies into caloric restriction which are interesting, as i have said before, but a lot remains unknown including but not limited to: if this approach will work out to be useful for ferrets, if there are nuances such as this best being done at certain ages, what medical conditions preclude use, how to best be sure to balance in the essential nutrients and optimal comfort levels (As I've also said before this may turn out to be best done with a future kibble type that incorporates a decent percentage of indigestible matter if the problems are overcome which might be associated with that such as bad effects on urine pH to debris in the stomach, to who knows what depending on the approach tried...), etc., etc., etc. I don't consider this an easy approach to try safely or comfortably (which is not to say that it can't be done, just that it needs careful care for comfort and safety), so i think that those who are interested need to discuss it with their vets and if the vet says it is okay to try then they need to work out beforehand with those health professionals or with a veterinary dietician how to do so most safely and which individuals to not try it on. (Of course, not trying it on the health compromised ones will make it look more good than reality, so in an unbiased study those considerations for individuals couldn't be made if the study purported to address the health of the general population, but I know that I wouldn't try something on one of our ferrets if a vet said it would be dangerous, and I am sure that is a common feeling here. Just know that eliminating compromised individuals definitely will skew results to the more glowing side.) [Posted in FML issue 3970]