The Russian fox domestication experiment, running since 1959, has produced the most compelling evidence for how domestication affects behavior, physiology, and welfare-relevant traits in animals.
The fox domestication experiment raises welfare questions beyond its scientific value. The foxes bred for tameness in the experiment have different welfare needs than wild foxes — they seek human company, show reduced fear responses, and are poorly equipped to survive independently. This creates a responsibility: once an animal is bred for tameness, its welfare becomes dependent on human provision of appropriate social contact and care. The foxes that were sold as pets faced welfare challenges because their needs — large spaces, specialist diets, and particular social structures — were poorly understood by purchasers. The lesson for welfare is that intentional creation of tame animals through selective breeding creates lasting welfare obligations.