Tameness of Rabbits
Darwin holds that in some cases selection alone has modified the instincts and dispositions of domesticated animals, but that in most cases selection and the inheritance of acquired habits have concurred in effecting the change. “On the other hand,” he says, “habit alone in some cases has sufficed; hardly any animal is more difficult to tame than the young of the wild rabbit; scarcely any animal is tamer than the young of the tame rabbit; but I can hardly suppose that domestic rabbits have often been selected for tameness alone; so that we must attribute at least the greater part of the inherited change from extreme wildness to extreme tameness to habit and long-continued close confinement.”42
But there are strong, and to me irresistible, arguments to the contrary. I think that the following considerations will show that the greater part, if not the whole, of the change must be attributed to selection rather than to the direct inheritance of acquired habit.
(1) For a period which may cover thousands of generations, there has been an entire cessation of the natural selection which maintains the wildness (or excessive fear, caution, activity, &c.) so indispensably essential for preserving defenceless wild rabbits of all ages from the many enemies that prey upon them.
(2) During this same extensive period of time man has usually killed off the wildest and bred from the tamest and most manageable. To some extent he has done this consciously. “It is very conducive to successful breeding to keep only such as are quiet and tractable,” says an authority on rabbits,43 and he enjoins the selection of the handsomest and best-tempered does to serve as breeders. To a still greater extent man has favoured tameness unconsciously and indirectly. He has systematically selected the largest and most prolific animals, and has thus doubled the size and the fertility of the domestic rabbit. In consciously selecting the largest and most flourishing individuals and the best and most prolific mothers, he must have unconsciously selected those rabbits whose relative tameness or placidity of disposition rendered it possible for them to flourish and to produce and rear large and thriving families, instead of fretting and pining as the wilder captives would do. When we consider how exceedingly delicate and easily disturbed yet all-important a function is that of maternity in the continually breeding rabbit, we see that the tamest and the least terrified would be the most successful mothers, and so would continually be selected, although man cared nothing for the tameness in itself. The tamest mothers would also be less liable to neglect or devour their offspring, as rabbits commonly do when their young are handled too soon, or even when merely frightened by mice, &c., or disturbed by changed surroundings.
(3) We must remember the extraordinary fecundity of the rabbit and the excessive amount of elimination that consequently takes place either naturally or artificially. Where nature preserved only the wildest, man has preserved the tamest. If there is any truth in the Darwinian theory, this thorough and long-continued reversal of the selective process must have had a powerful effect. Why should it not be amply sufficient to account for the tameness and mental degeneracy of the rabbit without the aid of a factor which can readily be shown to be far weaker in its normal action than either natural or artificial selection? Why may not the tameness of the rabbit be transferred to the group of cases in which Darwin holds that “habit has done nothing,” and selection has done all?
(4) If use-inheritance has tamed the rabbit, why are the bucks still so mischievous and unruly? Why is the Angora breed the only one in which the males show no desire to destroy the young? Why, too, should use-inheritance be so much more powerful in the rabbit than with other animals which are far more easily tamed in the first instance? Wild young rabbits when domesticated “remain unconquerably wild,” and, although they may be kept alive, they pine and “rarely come to any good.” Yet the animal which acquires least tameness—or apparently, indeed, none at all—inherits most! It appears, in fact, to inherit that which it cannot acquire—a circumstance which indicates the selection of spontaneous variations rather than the inheritance of changed habits. Such variations occasionally occur in animals in a marked degree. Of a litter of wolf-cubs, all brought up in the same way, “one became tame and gentle like a dog, while the others preserved their natural savagery.” Is it not probable that permanent domestication was rendered possible by the inevitable selection of spontaneous variations in this direction? The excessive tameness, too, of the young rabbit, while easily explicable as a result of unconscious selection, is not easily explained as a result of acquired habit. No particular care is taken to tame or teach or domesticate rabbits. They are bred for food, or for profit or appearance, and they are left to themselves most of their time. As Sir J. Sebright notices with some surprise, the domestic rabbit “is not often visited, and seldom handled, and yet it is always tame.”