The Ass.
Four species of Asses, besides three of zebras, have been described by naturalists; but there can now be little doubt that our domesticated animal is descended from one alone, namely, the Asinus tæniopus of Abyssinia.[[138]] The ass is sometimes advanced as an instance of an animal domesticated, as we know by the Old Testament, from an ancient period, which has varied only in a very slight degree. But this is by no means strictly true; for in Syria alone there are four breeds;[[139]] first, a light and graceful animal, with an agreeable gait, used by ladies; secondly, an Arab breed reserved exclusively for the saddle; thirdly, a stouter animal used for ploughing and various purposes; and lastly, the large Damascus breed, with a peculiarly long body and ears. In this country, and generally in Central Europe, though the ass is by no means uniform in appearance, it has not given rise to distinct breeds like those of the horse. This may probably be accounted for by the animal being kept chiefly by poor persons, who do not rear large numbers, nor carefully match and select the young. For, as we shall see in a future chapter, the ass can with ease be greatly improved in size and strength by careful selection, combined no doubt with good food; and we may infer that all its other characters would be equally amenable to selection. The small size of the ass in England and Northern Europe is apparently due far more to want of care in breeding than to cold; for in Western India, where the ass is used as a beast of burden by some of the lower castes, it is not much larger than a Newfoundland dog, "being generally not more than from twenty to thirty inches high."[[140]]
The ass varies greatly in colour; and its legs, especially the fore-legs, both in England and other countries—for instance, in China—are occasionally barred transversely more plainly than those of dun-coloured horses. With the horse the occasional appearance of leg-stripes was accounted for, through the principle of reversion, by the supposition that the primitive horse was
thus striped; with the ass we may confidently advance this explanation, for the parent-form, the A. tæniopus, is known to be barred, though only in a slight degree, across the legs. The stripes are believed to occur most frequently and to be plainest on the legs of the domestic ass during early youth,[[141]] as is apparently likewise the case with the horse. The shoulder-stripe, which is so eminently characteristic of the species, is nevertheless variable in breadth, length, and manner of termination. I have measured a shoulder-stripe four times as broad as another; and some more than twice as long as others. In one light-grey ass the shoulder-stripe was only six inches in length, and as thin as a piece of string; and in another animal of the same colour there was only a dusky shade representing a stripe. I have heard of three white asses, not albinoes, with no trace of shoulder or spinal stripes;[[142]] and I have seen nine other asses with no shoulder-stripe, and some of them had no spinal stripe. Three of the nine were light-greys, one a dark-grey, another grey passing into reddish-roan, and the others were brown, two being tinted on parts of their bodies with a reddish or bay shade. Hence we may conclude that, if grey and reddish-brown asses had been steadily selected and bred from, the shoulder-stripe would have been almost as generally and as completely lost as in the case of the horse.
The shoulder-stripe on the ass is sometimes double, and Mr. Blyth has seen even three or four parallel stripes.[[143]] I have observed in ten cases shoulder-stripes abruptly truncated at the lower end, with the anterior angle produced into a tapering point, precisely as has been figured in the dun Devonshire pony. I have seen three cases of the terminal portion abruptly and angularly bent; and two cases of a distinct though slight forking. In Syria, Dr. Hooker and his party observed for me no less than five instances of the shoulder-stripe being plainly forked over the fore leg. In the common mule it is likewise sometimes forked. When I first noticed the forking and angular bending of the shoulder-stripe, I had seen enough of the stripes
in the various equine species to feel convinced that even a character so unimportant as this had a distinct meaning, and was thus led to attend to the subject. I now find that in the Asinus Burchellii and quagga, the stripe which corresponds with the shoulder-stripe of the ass, as well as some of the stripes on the neck, bifurcate, and that some of those near the shoulder have their extremities angularly bent backwards. The forking and angular bending of the stripes on the shoulders apparently stand in relation with the changed direction of the nearly upright stripes on the sides of the body and neck to the transverse bars on the legs. Finally we see that the presence of shoulder, leg, and spinal stripes in the horse,—their occasional absence in the ass,—the occurrence of double and triple shoulder-stripes in both animals, and the similar manner in which these stripes terminate at their lower extremities,—are all cases of analogous variation in the horse and ass. These cases are probably not due to similar conditions acting on similar constitutions, but to a partial reversion in colour to the common progenitor of these two species, as well as of the other species of the genus. We shall hereafter have to return to this subject, and discuss it more fully.