Q: "You...mentioned that ferrets have not been subjected to the 'dumbing down rule of domestication.' I'm not sure I agree with that.... Some of this may well be attributable to the lack of stimulation and variable environments at an early age...but all of it??" A: Ferrets may not have been subjected to the dumbing down rule, but I think I have been... ;-) A domesticated animal is one that is in human control, selectively bred by humans, maintained (housed, fed) for human use, and has had at least one characteristic (color, size, behavior, etc.) changed to meet human desire. This is a modern and well-accepted definition, but it isn't too far from Darwin's original definition (1859, 1868) which included being oriented towards achieving some human-goal, captive breeding, morphological changes (defined as increased fecundity, atrophy of certain organs, smaller size, more variation), can happen without conscious human effort, and the ever-important "tameness towards humans" (a common Victorian requirement). It was this last requirement that continues to cause some sticky problems regarding ferret domestication. Essentially, Darwin anthrocentrically argued the more domesticated a species, the tamer it was towards humans (the dog being the archetypical example). Yet, animals that were not as tame towards people as others were still clearly in a state of domestication, so the conundrum was answered by using the term "semi-domesticated." Thus Victorian scientists ignored the reactions of feral and abandoned dogs and cats towards people, but seized on the reactions of poorly handled, badly socialized ferrets, labeling them "semi-domesticated." Thankfully, excepting those Wizards of Obtuseness, the CaCaLand Fishing Gestapo and Cranioanal Impaction League, the idea of an animal being "semi-domesticated" has been largely abandoned in favor of a more enlightened theory of domestication. One of the observations made during this early demarcation of domestication was that changes took place in the size and shape of the skull. Generally, the facial bones of the skull are shortened, giving the animal a more juvenile, pug-like face. Another observation was that the cranial volume, the measure of the space that houses the brain, was smaller in domesticated animals. Some animal behaviorists, seizing on the differences in behavior observed between domesticated animals and their wild progenitors, suggested domesticated animals were not as intelligent, the infamous "dumbing-down rule of domestication". Later investigations suggested the brain of domesticated animals was smaller, but the difference in size reflected smaller sensory regions of the brain, and not necessarily regions impacting intelligence. Nonetheless, people working with both wild and domesticated animals could intuitively tell that wild animals were somehow smarter than their domesticated counterparts, so the "dumbing-down" rule became part of the common knowledge of domestication. Research done during the last few decades has called this common knowledge into question. It has been discovered that developing brains are extremely plastic in their responses to environmental influences (that is, capable of adapting to different conditions during early development). For example, ferret kits that are exposed to lots of different odors will have more nerve connections to the areas of the brain sensing smell; they can detect more odors and the brain can interpret them better (the basis of olfactory imprinting). The effects of the visual environment on the growth of specific eye structures is astounding; just the prevalence of predominately vertical lines over horizontal ones can change the development of several structures within the eye, optic nerve and brain (meaning cage environments can literally result in different vision compared to those raised outside cages). The early separation of babies from their mothers has been shown- -across species- -to result in profound changes in the brain, which one recent paper has demonstrated to be minimized by an aggressive enrichment program during juvenile development. Environment has such a profound influence on brain development that it can even influence mental concepts of gender, as shown in studies of identical twins (genetic clones) where one has gender-specific sexual orientation, and the other feels trapped in the wrong body. Bob C [Posted in FML issue 4314]