“In Europe, the milking of cows is continued through the whole period, from the time when they begin to bear calves till they cease to breed. This secretion of milk has become a constant function in the animal economy of the tribe; it has been rendered such by the practice, continued through long series of generations, of continuing to draw milk long after the period when it would be wanted for the calf; the teats of the cow are larger than in proportion, and the secretion is perpetual. In Columbia, the practice of milking cows was laid aside, owing to the great extent of farms and other circumstances. ‘In a few generations,’ says M. Roulin, ‘the natural structure of parts, and withal, the natural state of the function, has been restored. The secretion of milk in the cow of this country is only an occasional phenomenon, and contemporary with the actual presence of the calf. If the calf dies, the milk ceases to flow, and it is only by keeping him with his dam by day, that an opportunity of obtaining milk from cows by night can be found.’ This testimony is important, by the proof which it affords that the permanent production of milk in the European breeds of cows is a modified function of the animal economy, produced by an artificial habit continued through several generations. Two other very important observations made by M. Roulin in South America, were pointed out by M. Geoffrey St Hilaire in his report to the Academy of Sciences. They refer to the fact of the hereditary transmission of habits originally impressed with care and art upon the ancestors. Of this fact I shall adduce other examples in the sequel; at present I only advert to M. Roulin’s observations. The horses bred in the grazing farms on the table-land of the Cordillera, are carefully taught a peculiar pace, which is a sort of running amble. This is not their natural mode of progression, but they are inured to it very early, and the greatest pains are taken to prevent them from moving in any other gait. In this way the acquired habit becomes a second nature. It happens occasionally that such horses, becoming lame, are no longer fit for use; it is then customary to let them loose, if they happen to be well-grown stallions, into the pasture grounds. It is constantly observed that these horses become the sires of a race to which the ambling pace is natural, and requires no teaching. The fact is so well known, that such colts have received a particular name; they are termed ‘aguilillas.’
“The second fact is, the developement of a new instinct, which, as M. Roulin declares, seems to become hereditary in the breed of dogs found among the borderers on the river Madeleine, which are employed in hunting the pecari. I shall cite the author’s own words:—‘L’addresse du chien consiste à modérer son ardeur à ne s’attacher à aucun animal en particulier, mais à tenir toute la troupe en échec. Or, parmi ces chiens, on en volt maintenant qui, la première fois qu’on les amène au bois, savent dejà comment attaquer; un chien d’une autre espèce se lance tout d’abord, est environné, et quelle que soit sa force, il est dévoré dans un instant.’”
To these cases we may add a case familiar to the sportsmen of this country, and one of which we have ourselves seen an unquestionable instance, viz. the acquired habit of the setting-dog in arresting his steps, and crouching, when in pursuit of game; the origin of which was probably a pause in his career, in order the better to ascertain the position of the game of which he was in quest; but this, by constant teaching, has become hereditary to such an extent, that occasionally a dog of pure breed will, the first time he is taken out, as soon as he gets on the scent of game, crouch or place himself in a setting attitude, and remain perfectly immobile until forced to proceed; nay further—as it is necessary that the sportsman teach the dogs who are in the same field with that one who discovers the game, as soon as they see the latter setting to arrest their steps likewise; or, as it is termed, to back, in order not to disturb the game—in the instance which came under our notice, a dog of eight or nine months old, which had never been out of a town, when taken into the fields for the first time with an old well-trained dog, as soon as the latter had discovered game, and pointed to it, instantly backed him—i.e. remained stiffly standing in the position in which he was when he first caught sight of the older dog: probably many sportsmen could be found who would vouch to similar facts.
We may here state that we quite agree with Dr Prichard, as to the absence of any foundation for the general belief, that all the acts of inferior animals are performed without their consciousness or view to any object or end; on the contrary, there is every probability that they, in carrying into effect their several instincts, seem to themselves to act from similar internal impulses of will and intention, as human beings do.
We need not enter into the vast number of varieties which the most domestic of all domesticated animals, the dog, exhibits; we shall only remark, that, in all their varieties, Dr Prichard says,—
“Restored to a state of comparative wildness, which approaches to their unreclaimed and primitive condition, the tribes of dogs every where make a corresponding approximation to the type which may be supposed to have belonged to the species in its original state.”
But this passage is enigmatical, as the original type seems to be involved in dense obscurity. Buffon considered the shepherd dog to be the least modified by domestication—very erroneously, according to Dr Prichard; it is still a vexata questio, whether the original progenitor of the dog be a wolf, a jackal, a fox, or an unknown animal differing from all these.
“The sheep is one of the most anciently domesticated animals, and it is one in which great varieties display themselves. It has been long believed, and this appears to have been the opinion of Baron Cuvier, that all the breeds of tamed sheep are descended either from the argali of Siberia, or from the moufloun or musmon of Barbary. This is at present doubted by most naturalists. There seems, however, to be no reason for believing that the domestic breeds belong to more than one species, though they differ much in different countries. In Europe, the breeds of sheep vary much in stature, in the texture of their wool, the number and shape of their horns, which are in some large, in some small, in others wanting to the female, or altogether absent from the breed. The most important varieties in Europe are the Spanish breeds, some with fine, others with crisp wool, in which the rams have long spiral horns; the English breeds, which differ greatly in size and in the quality of the wool; and, in the southern parts of Russia, the long-tailed breed. The breeds of sheep in India and in Africa are remarkable for the length of their legs, a very convex forehead, and pendant ears; these also have long tails. Their covering is not wool, but a smooth hair. In the northern parts of Europe and Asia the sheep have short tails. The breeds spread through Persia, Tartary, and China, have their tails transformed into a double spherical mass of fat. The sheep of Syria and Barbary, on the other hand, have long tails, but likewise loaded with a mass of fat. In both of these varieties of the sheep the ears are pendant, the horns of the rams large, and those of the ewes and lambs of moderate size, and the body is covered with wool, mixed more or less with hair.
“New breeds of sheep are frequently formed in different countries in which particular qualities predominate, according to the preference of the breeders. This is done, partly by crossing or intermixing races already constituted and well known; but in great part also by selecting individuals from the stock in which the particular qualities are more strongly marked than in the generality of the same breed. In these instances, the natural or congenital variety which the individual animal displays, perhaps for the first time, becomes perpetuated by the hereditary transmission of such characters, which is a law of the animal economy. A striking instance of this fact is to be found in the origination of a new breed of sheep in the state of Massachusetts, which has been noticed by many writers in connexion with this subject. In the year 1791, one ewe on the farm of Seth Wright gave birth to a male lamb, which, without any known cause, had a longer body and shorter legs than the rest of the breed. The joints are said to have been longer, and the fore-legs crooked. The shape of this animal rendering it unable to leap over fences, it was determined to propagate its peculiarities, and the experiment proved successful; a new race of sheep was produced, which, from the form of the body, has been termed the otter breed. It seems to be uniformly the fact, that when both parents are of the otter breed, the lambs that are produced inherit the peculiar form.”
We might extract other instances of physiological and psychological changes induced by domestication, but we think enough have been given to show the character and degree of such changes. The least important change, and that which appears the soonest affected, is the colour of the skin and hair. This is universally of an uniform tint in wild animals, and generally bears a close approximation to the colour of the land in which the animal lives: thus the ptarmigan, inhabiting snowy regions, is white; the grouse has the colour of heath; the hare that of dry fern or furze—a provision which has the effect of protecting the weaker tribes from the stronger and predatory ones. In domesticated animals, from causes apparently not as yet traced, the colour is variegated and various. Closely connected with the colour and nature of the skin, are the size and shape of the horns, their presence and absence. Great as is the apparent variety of appearance effected by horns, changes in these appear to be easily induced: they are connected with the epidermic structure, generally the most easily modified; and we need not cite instances to prove that different breeds of the same tribe, and occasionally different individuals of the same breed, differ materially as to horns. According to Azara, horned horses are sometimes seen in Paraguay.