What makes the mice nice

Domestication has a long history. It predates the invention of writing by thousands of years. In the history of biology the study of domestication is closely connected to the emergence of experimental and theoretical biology out of the shadow of natural history. Chapter I of The Origin of Species is preoccupied with animal breeding. The various modifiers of selection, artificial, natural and sexual, are to some extent human constructions. When the constraint of human preferences and needs are removed feral populations of dogs and pigs tend to shift back toward an ancient modal wild type. I hesitate to use a term such as "primitive" because of its pejorative connotations. Wolves after all are more intelligent than dogs, and this is probably true of most domesticates in relation to their wild ancestors. This makes sense, human intelligence to some extent serves as a substitute for the reasoning skills of our domesticated animals, and since the brain is an energentically expensive organ perhaps there is a natural "relaxation" of selective constraint? Of course despite being duller in a general sense, domestic dogs do have special adaptations. They can read human mental states more subtly than much more intelligent animals, such as chimpanzees. Lapdogs, despite their often bizarre morphology and obnoxious behavior clearly have an adaptively fit niche. Working dog breeds, such as those who herd sheep, retain greater autonomous intelligence. And so forth. An interesting point brought up by the power of selection to reshape dogs bodily and behaviorally, and their differences from the wolf parental populations from which they derive, is how much insight we can gain of human evolution. The Nobel Prize winning ethologist Konrad Lorenz suggested that humans were "degrading" due to a process of self-domestication. Human cranial capacities may exhibit a long term secular increase, but I have heard that they may have peaked during the Last Glacial Maximum, and have been subject to decline as is true of size in general. The study of the genetics of domestication is not simply one of natural history, it is a fertile applied science. One of the most fascinating pure research programs has been that of the famous Russian "domestic foxes," who are derived from wild fox lineages but have over time been selected for traits which have turned them into analogs of domestic dogs. A new paper which explores similar dynamics in rats just came out, Genetic Architecture of Tameness in a Rat Model of Animal Domestication: