SigPhi · Charles Darwin

The Variation of Animals and Plants under Domestication

English

Page 5 of 70

adds that the change has been less at Ascension, the capital of Paraguay, owing to the continual crossing with newly imported cats; and this fact well illustrates the importance of separation. The conditions of life in Paraguay appear not to be highly favourable to the cat, for, though they have run half-wild, they do not become thoroughly feral, like so many other European animals. In another part of South America, according to Roulin,[94] the introduced cat has lost the habit of uttering its hideous nocturnal howl. The Rev.

W.D. Fox purchased a cat in Portsmouth, which he was told came from the coast of Guinea; its skin was black and wrinkled, fur bluish-grey and short, its ears rather bare, legs long, and whole aspect peculiar. This “negro” cat was fertile with common cats. On the opposite coast of Africa, at Mombas, Captain Owen, R.N.,[95] states that all the cats are covered with short stiff hair instead of fur: he gives a curious account of a cat from Algoa Bay, which had been kept for some time on board and could be identified with certainty; this animal was left for only eight weeks at Mombas, but during that short period it “underwent a complete metamorphosis, having parted with its sandy-coloured fur.” A cat from the Cape of Good Hope has been described by Desmarest as remarkable from a red stripe extending along the whole length of its back. Throughout an immense area, namely, the Malayan archipelago, Siam, Pegu, and Burmah, all the cats have truncated tails about half the proper length,[96] often with a sort of knot at the end. In the Caroline archipelago the cats have very long legs, and are of a reddish-yellow colour.[97] In China a breed has drooping ears. At Tobolsk, according to Gmelin, there is a red-coloured breed. In Asia, also, we find the well-known Angora or Persian breed.

The domestic cat has run wild in several countries, and everywhere assumes, as far as can be judged by the short recorded descriptions, a uniform character. Near Maldonado, in La Plata, I shot one which seemed perfectly wild; it was carefully examined by Mr. Waterhouse,[98] who found nothing remarkable in it, excepting its great size. In New Zealand according to Dieffenbach, the feral cats assume a streaky grey colour like that of wild cats; and this is the case with the half-wild cats of the Scotch Highlands.

We have seen that distant countries possess distinct domestic races of the cat. The differences may be in part due to descent from several aboriginal species, or at least to crosses with them. In some cases, as in Paraguay, Mombas, and Antigua, the differences seem due to the direct action of different conditions of life. In other cases some slight effect may possibly be attributed to natural selection, as cats in many cases have largely to support themselves and to escape diverse dangers. But man, owing to the difficulty of pairing cats, has done nothing by methodical selection; and probably very little by unintentional selection; though in each litter he generally saves the prettiest, and values most a good breed of mouse- or rat-catchers.

Those cats which have a strong tendency to prowl after game, generally get destroyed by traps. As cats are so much petted, a breed bearing the same relation to other cats, that lapdogs bear to larger dogs, would have been much valued; and if selection could have been applied, we should certainly have had many breeds in each long-civilised country, for there is plenty of variability to work upon.

We see in this country considerable diversity in size, some in the proportions of the body, and extreme variability in colouring. I have only lately attended to this subject, but have already heard of some singular cases of variation; one of a cat born in the West Indies toothless, and remaining so all its life. Mr. Tegetmeier has shown me the skull of a female cat with its canines so much developed that they protruded uncovered beyond the lips; the tooth with the fang being.95, and the part projecting from the gum.6 of an inch in length. I have heard of several families of six-toed cats, in one of which the peculiarity had been transmitted for at least three generations. The tail varies greatly in length; I have seen a cat which always carried its tail flat on its back when pleased. The ears vary in shape, and certain strains, in England, inherit a pencil-like tuft of hairs, above a quarter of an inch in length, on the tips of their ears; and this same peculiarity, according to Mr. Blyth, characterises some cats in India. The great variability in the length of the tail and the lynx-like tufts of hairs on the ears are apparently analogous to differences in certain wild species of the genus. A much more important difference, according to Daubenton,[99] is that the intestines of domestic cats are wider, and a third longer, than in wild cats of the same size; and this apparently has been by their less strictly carnivorous diet.

Canidæ,’ p. 142, has largely discussed the whole subject, and concludes that the extinct parent of all domesticated dogs came nearest to the wolf in organisation, and to the jackal in habits. _See also_ Boyd Dawkins, ‘Cave Hunting,’ 1874, p. 131, etc., and his other publications. Jeitteles has discussed in great detail the character of the breeds of pre-historic dogs: ‘Die vorgeschichtlichen Alterthümer der Stadt Olmütz,’ II. Theil, 1872, p. 44 to end.

[2] Pallas, I believe, originated this doctrine in ‘Act. Acad. St.

Petersburgh,’ 1780, Part ii. Ehrenberg has advocated it, as may be seen in De Blainville’s ‘Ostéographie,’ p. 79. It has been carried to an extreme extent by Col. Hamilton Smith in the ‘Naturalist Library,’ vols ix and x. Mr. W. C. Martin adopts it in his excellent ‘History of the Dog,’ 1845; as does Dr. Morton, as well as Nott and Gliddon, in the United States. Prof. Low, in his ‘Domesticated Animals,’ 1845, p.

666, comes to this same conclusion. No one has argued on this side with more clearness and force than the late James Wilson, of Edinburgh, in various papers read before the Highland Agricultural and Wernerian Societies. Isidore Geoffroy Saint-Hilaire (‘Hist. Nat.

Gén.,’ 1860, tom. iii. p. 107), though he believes that most dogs have descended from the jackal, yet inclines to the belief that some are descended from the wolf. Prof. Gervais (‘Hist. Nat. Mamm.’ 1855, tom.

ii. p. 69, referring to the view that all the domestic races are the modified descendants of a single species, after a long discussion, says, “Cette opinion est, suivant nous du moins, la moins probable.”

[3] Berjeau, ‘The Varieties of the Dog; in old Sculptures and 48: this author seems carefully to have studied all classical works on the subject. _See also_ Volz, ‘Beiträge zur Kulturgeschichte,’ history is given by De Blainville in his ‘Ostéographie, Canidæ.’

[4] I have seen drawings of this dog from the tomb of the son of Esar Haddon, and clay models in the British Museum. Nott and Gliddon, in their ‘Types of Mankind,’ 1854, p. 393, give a copy of these drawings.

This dog has been called a Thibetan mastiff, but Mr. H. A. Oldfield, who is familiar with the so-called Thibet mastiff, and has examined the drawings in the British Museum, informs me that he considers them different.

[7] Berjeau gives facsimiles of the Egyptian drawings. Mr. C. L.

Martin in his ‘History of the Dog,’ 1845, copies several figures from the Egyptian monuments, and speaks with much confidence with respect to their identity with still living dogs. Messrs. Nott and Gliddon (‘Types of Mankind,’ 1854, p. 388) give still more numerous figures.

Mr. Gliddon asserts that a curl-tailed greyhound, like that represented on the most ancient monuments, is common in Borneo; but the Rajah, Sir J. Brooke, informs me that no such dog exists there.

[8] These, and the following facts on the Danish remains, are taken from M. Morlot’s most interesting memoir in ‘Soc. Vaudoise des Sc.

[11] Sir R. Schomburgk has given me information on this head. _See _Canis antarcticus, see_ p. 193. For the case of the antelope, _see_ ‘Journal Royal Geograph. Soc.,’ vol. xxiii. p. 94.

[14] The authorities for the foregoing statements are as p. 269, gives the case of three whelps of a black wolf being carried away by the Indians. Parry, Richardson, and others, give accounts of wolves and dogs naturally crossing in the eastern parts of North America. Seeman in his ‘Voyage of H.M.S. _Herald_,’ 1853, vol. ii. p.

26, says the wolf is often caught by the Esquimaux for the purpose of crossing with their dogs, and thus adding to their size and strength.

M. Lamare-Picquot in ‘Bull. de la Soc. d’Acclimat,’ tom. vii., 1860, p. 148, gives a good account of the half-bred Esquimaux dogs.

Gliddon, ‘Types of Mankind,’ p. 383. The naturalist and traveller Bartram is quoted by Hamilton Smith, in ‘Naturalist Lib.,’ vol. x. p.

156. A Mexican domestic dog seems also to resemble a wild dog of the same country; but this may be the prairie-wolf. Another capable judge, Mr. J. K. Lord (‘The Naturalist in Vancouver Island,’ 1866, vol. ii.

p. 218), says that the Indian dog of the Spokans, near the Rocky Mountains, “is beyond all question nothing more than a tamed Cayote or [16] I quote this from Mr. R. Hill’s excellent account of the Alco or domestic dog of Mexico, in Gosse’s ‘Naturalist’s Sojourn in Jamaica,’ 1851, p. 329.

[18] Quoted in Humboldt’s ‘Aspects of Nature’ (Eng. trans.), vol. i.

p. 108.

of the World’ (Eng. trans.), 8th book, ch. xl., about the Gauls crossing their dogs. _See also_ Aristotle ‘Hist. Animal.’lib. viii. c.

28. For good evidence about wolves and dogs naturally crossing near the Pyrenees, _see_ M. Mauduyt ‘Du Loup et de ses Races,’ Poitiers, 1851; also Pallas in ‘Acta Acad. St. Petersburgh,’ 1780, part ii. p.

94.

[20] I give this on excellent authority, namely Mr. Blyth (under the signature of Zoophilus), in the ‘Indian Sporting Review,’ Oct. 1856, p. 134. Mr. Blyth states that he was struck with the resemblance between a brush-tailed race of pariah-dogs, north-west of Cawnpore, and the Indian wolf. He gives corroborative evidence with respect to the dogs of the valley of the Nerbudda.

[21] For numerous and interesting details on the resemblance of dogs and jackals _see_ Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’ 1860, tom. iii. p. 101. _ See also_ ‘Hist. Nat. des Mammifères,’ par Prof.

Gervais, 1855, tom. ii. p. 60.

[22] Also Güldenstädt ‘Nov. Comment. Acad. Petrop.,’ tom. xx., pro anno 1775, p. 449. Also Salvin in ‘Land and Water,’ Oct. 1869.

[23] Quoted by De Blainville in his ‘Ostéographie, Canidæ,’ pp. 79, 98.

[24] _See_ Pallas in ‘Act. Acad. St. Petersburgh,’ 1780, part ii. p.

91. For Algeria, _see_ Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’ tom. iii. p. 177. In both countries it is the male jackal which pairs with female domestic dogs.

[25] John Barbut’s ‘Description of the Coast of Guinea in 1746.’

[27] Selwyn, Geology of Victoria; ‘Journal of Geolog. Soc.,’ vol.

xiv., 1858, p. 536, and vol. xvi., 1860, p. 148; and Prof. M’Coy, in ‘Annals and Mag. of Nat. Hist.’ (3rd series) vol. ix., 1862, p. 147.

The Dingo differs from the dogs of the central Polynesian islands.

Dieffenbach remarks (‘Travels,’ vol. ii. p. 45) that the native New Zealand dog also differs from the Dingo.

[28] These latter remarks afford, I think, a sufficient answer to some criticisms by Mr. Wallace, on the multiple origin of dogs, given in taming of the common wolf, L. Lloyd, ‘Scandinavian Adventures,’ 1854, vol. i. p. 460. With respect to the jackal, _see_ Prof. Gervais ‘Hist.

Nat. Mamm.’ tom. ii. p. 61. With respect to the aguara of Paraguay [30] Roulin, in ‘Mém. présent. par divers Savans,’ tom. vi. p. 341.

[32] Quoted by L. Lloyd in ‘Field Sports of North of Europe,’ vol. i.

p. 387.

[34] ‘Annals and Mag. of Nat. Hist.’ vol. xv., 1845, p. 140.

is fully confirmed by Rengger. Quatrefages gives an account of a bitch brought from Jerusalem to France which burrowed a hole and littered in [36] With respect to wolves burrowing holes _ see_ Richardson, ‘Fauna above; and Rengger, s. 155.

[38] Dogs, ‘Nat. Library,’ vol. x. p. 121; an endemic South American dog seems also to have become feral in this island. _See_ Gosse’s ‘Jamaica,’ p. 340.

[41] Quoted by Prof. Gervais, ‘Hist. Nat. Mamm.,’ tom. ii. p. 66.

[42] J. Hunter shows that the long period of seventy-three days given by Buffon is easily explained by the bitch having received the dog many times during a period of sixteen days (‘Phil. Transact.,’ 1787, p. 353). Hunter found that the gestation of a mongrel from wolf and for she received the dog more than once. The period of a mongrel dog and jackal was fifty-nine days. Fred. Cuvier found the period of gestation of the wolf to be (‘Dict. Class. d’Hist. Nat.’ tom. iv. p.

8) two months and a few days, which agrees with the dog. Isid G.

St.-Hilaire, who has discussed the whole subject, and from whom I quote Bellingeri, states (‘Hist. Nat. Gén.,’ tom. iii. p. 112) that in the Jardin des Plantes the period of the jackal has been found to be from sixty to sixty-three days, exactly as with the dog.

112, on the odour of jackals. Col. Ham. Smith in ‘Nat. Lib.,’ vol. x.

p. 289.

[44] Quoted by Quatrefages in ‘Bull. Soc. d’Acclimat.,’ May 11th, 1863.

[46] _See_ Mr. R. Hill’s excellent account of this breed in Gosse’s respect to Spitz dogs, _see_ Bechstein’s ‘Naturgesch. Deutschlands,’ 1801, B. i. s. 638. With respect to Dr. Hodgkin’s statement made before Brit. Assoc. _see_ ‘The Zoologist,’ vol. iv. for 1845-46 p.

1097.

[48] M. Broca has shown (‘Journal de Physiologie,’ tom. ii. p. 353) that Buffon’s experiments have been often misrepresented. Broca has collected (pp. 390-395) many facts on the fertility of crossed dogs, wolves, and jackals.

Blyth says (‘Indian Sporting Review,’ vol. 2 p. 137) that he has seen in India several hybrids from the pariah-dog and jackal; and between one of these hybrids and a terrier. The experiments of Hunter on the Nat. Gén.,’ tom. iii. p. 217, who speaks of the hybrid offspring of the jackal as perfectly fertile for three generations.

[50] On authority of F. Cuvier quoted in Bronn’s ‘Geschichte der King, after ample opportunities of observation, informs me that the Dingo and European dogs often cross in Australia.

39 pl. xiv. There is a specimen of this fine animal in the British Museum.

[54] Quoted by I. Geoffroy, ‘Hist. Nat. Gén.,’ tom. iii. p. 453.

ix. p. 101. _See also_ some observations on the degeneracy of the skull in certain breeds, by Prof. Bianconi, ‘La Theorie Darwinienne,’ 1874, p. 279.

[56] Dr. Burt Wilder, ‘American Assoc. Advancement of Science,’ 1873, pp. 236, 239.

Blainville (‘Ostéographie, Canidæ,’ p. 137) has also seen an extra molar on both sides.

[60] Mr. Yarrell in ‘Proc. Zoolog. Soc.,’ Oct. 8th, 1833. Mr.

Waterhouse showed me a skull of one of these dogs, which had only a single molar on each side and some imperfect incisors.

[61] Quoted in ‘The Veterinary,’ London, vol. viii. p. 415.

[62] This is quoted from Stonehenge, a great authority, ‘The Dog,’ 1867, p. 187.

[65] Quoted by Col. Ham. Smith in ‘Nat. Lib.,’ vol. x. p. 79.

du Muséum,’ tom. xviii. p. 342. In regard to mastiffs, _see_ Col. H.

Smith ‘Nat. Lib.’ vol. x. p. 218. For the Thibet mastiff, _see_ Mr.

Hodgson in ‘Journal of As. Soc. of Bengal,’ vol. i., 1832, p. 342.

[67] ‘The Dog,’ 1845, p. 186. With respect to diseases Youatt asserts (p. 167) that the Italian greyhound is “strongly subject” to polypi in the matrix or vagina. The spaniel and pug (p. 182) are most liable to bronchocele. The liability to distemper (p. 232) is extremely different in different breeds. On the distemper, _see also_ Col.

[68] _See_ Youatt on the Dog, p. 15; ‘The Veterinary,’ London, vol.

xi. p. 235.

[69] ‘Journal of As. Soc. of Bengal,’ vol. iii. p. 19.

[71] Hodgson in ‘Journal of As. Soc. of Bengal,’ vol. i. p. 342.

[72] ‘Field Sports of the North of Europe,’ vol. ii. p. 165.

[76] A. Murray gives this passage in his ‘Geographical Distribution of [77] Quoted by Mr. Galton, ‘Domestication of Animals,’ p. 13.

[79] Mr. Greenhow on the Canadian Dog in Loudon’s ‘Mag. of Nat.

[80] _See_ Mr. C. O. Groom-Napier on the webbing of the hind feet of [82] ‘The Horse in all his Varieties,’ etc., 1829, pp. 230, 234.

spaniel, p. 45; for the setter, p. 90.

[85] Author of ‘Researches into the History of the British Dog.’

[86] _See_ Col. Hamilton Smith on the antiquity of the Pointer, in [87] The Newfoundland dog is believed to have originated from a cross between the Esquimaux dog and a large French hound. _See_ Dr. Hodgkin about Newfoundland.’

[88] De Blainville ‘Ostéographie, Felis,’ p. 65, on the character of _F. caligulata_; pp. 85, 89, 90, 175, on the other mummied species. He quotes Ehrenberg on _F. maniculata_ being mummied.

[89] Asiatic Soc. of Calcutta; Curator’s Report, Aug. 1856. The passage from Sir W. Jardine is quoted from this Report. Mr. Blyth, who has especially attended to the wild and domestic cats of India, has given in this Report a very interesting discussion on their origin.

[91] Isid. Geoffroy Saint-Hilaire, ‘Hist. Nat. Gén.,’ tom. iii. p.

177.

[94] ‘Mem. présentés par divers Savans: Acad. Roy. des Sciences,’ tom.

vi. p. 346. Gomara first noticed this fact in 1554.

[96] J. Crawfurd ‘Descript. Dict. of the Indian Islands,’ p. 255. The Madagascar cat is said to have a twisted tail; _see_ Desmarest in ‘Encyclop. Nat. Mamm.,’ 1820, p. 233, for some of the other breeds.

[97] Admiral Lutké’s Voyage, vol. iii. p. 308.

[98] ‘Zoology of the Voyage of the Beagle, Mammalia,’ p. 20.

Dieffenbach ‘Travels in New Zealand,’ vol. ii. p. 185. Ch. St. John [99] Quoted by Isid. Geoffroy ‘Hist. Nat. Gén.,’ tom. iii. p. 427.

CHAPTER II. HORSES AND ASSES.

HORSE. DIFFERENCES IN THE BREEDS—INDIVIDUAL VARIABILITY OF—DIRECT EFFECTS OF THE CONDITIONS OF LIFE—CAN WITHSTAND MUCH COLD—BREEDS MUCH MODIFIED BY SELECTION—COLOURS OF THE HORSE—DAPPLING—DARK STRIPES ON THE SPINE, LEGS, SHOULDERS, AND FOREHEAD—DUN-COLOURED HORSES MOST FREQUENTLY STRIPED—STRIPES PROBABLY DUE TO REVERSION TO THE PRIMITIVE STATE OF THE HORSE.

ASSES. BREEDS OF—COLOUR OF—LEG- AND SHOULDER-STRIPES—SHOULDER-STRIPES SOMETIMES ABSENT, SOMETIMES FORKED.

The history of the Horse is lost in antiquity. Remains of this animal in a domesticated condition have been found in the Swiss lake-dwellings, belonging to the Neolithic period.[1] At the present time the number of breeds is great, as may be seen by consulting any treatise on the Horse.[2] Looking only to the native ponies of Great Britain, those of the Shetland Isles, Wales, the New Forest, and Devonshire are distinguishable; and so it is, amongst other instances, with each separate island in the great Malay archipelago.[3] Some of the breeds present great differences in size, shape of ears, length of mane, proportions of the body, form of the withers and hind quarters, and especially in the head.

Compare the race-horse, dray-horse, and a Shetland pony in size, configuration, and disposition; and see how much greater the difference is than between the seven or eight other living species of the genus Equus.

Of individual variations not known to characterise particular breeds, and not great or injurious enough to be called monstrosities, I have not collected many cases. Mr. G. Brown, of the Cirencester Agricultural College, who has particularly attended to the dentition of our domestic animals, writes to me that he has “several times noticed eight permanent incisors instead of six in the jaw.” Male horses only should have canines, but they are occasionally found in the mare, though a small size.[4] The number of ribs on each side is properly eighteen, but Youatt[5] asserts that not unfrequently there are nineteen, the additional one being always the posterior rib. It is a remarkable fact that the ancient Indian horse is said in the Rig-Vêda to have only seventeen ribs; and M. Piétrement,[6] who has called attention to this subject, gives various reasons for placing full trust in this statement, more especially as during former times the Hindoos carefully counted the bones of animals. I have seen several notices of variations in the bones of the leg; thus Mr. Price[7] speaks of an additional bone in the hock, and of certain abnormal appearances between the tibia and astragalus, as quite common in Irish horses, and not due to disease. Horses have often been observed, according to M. Gaudry,[8] to possess a trapezium and a rudiment of a fifth metacarpal bone, so that “one sees appearing by monstrosity, in the foot of the horse, structures which normally exist in the foot of the Hipparion,”—an allied and extinct animal. In various countries horn-like projections have been observed on the frontal bones of the horse: in one case described by Mr. Percival they arose about two inches above the orbital processes, and were “very like those in a calf from five to six months old,” being from half to three-quarters of an inch in length.[9] Azara has described two cases in South America in which the projections were between three and four inches in length: other instances have occurred in Spain.

That there has been much inherited variation in the horse cannot be doubted, when we reflect on the number of the breeds existing throughout the world or even within the same country, and when we know that they have largely increased in number since the earliest known records.[10] Even in so fleeting a character as colour, Hofacker[11] found that, out of 216 cases in which horses of the same colour were paired, only eleven pairs produced foals of a quite different colour. As Professor Low[12] has remarked, the English race-horse offers the best possible evidence of inheritance. The pedigree of a race-horse is of more value in judging of its probable success than its appearance: “King Herod” gained in prizes 201,505 pounds sterling, and begot 497 winners; “Eclipse” begot 334 winners.

Whether the whole amount of difference between the various breeds has arisen under domestication is doubtful. From the fertility of the most distinct breeds[13] when crossed, naturalists have generally looked at all the breeds as having descended from a single species. Few will agree with Colonel H. Smith, who believes that they have descended from no less than five primitive and differently coloured stocks.[14] But as several species and varieties of the horse existed[15] during the later tertiary periods, and as Rutimeyer found differences in the size and form of the skull in the earliest known domesticated horses,[16] we ought not to feel sure that all our breeds are descended from a single species. The savages of North and South America easily reclaim the feral horses, so that there is no improbability in savages in various quarters of the world having domesticated more than one native species or natural race. M. Sanson[17] thinks that he has proved that two distinct species have been domesticated, one in the East, and one in North Africa; and that these differed in the number of their lumbar vertebra and in various other parts; but M.

Sanson seems to believe that osteological characters are subject to very little variation, which is certainly a mistake. At present no aboriginal or truly wild horse is positively known to exist; for it is commonly believed that the wild horses of the East are escaped domestic animals.[18] If therefore our domestic breeds are descended from several species or natural races, all have become extinct in the wild state.

With respect to the causes of the modifications which horses have undergone, the conditions of life seem to produce a considerable direct effect. Mr. D. Forbes, who has had excellent opportunities of comparing the horses of Spain with those of South America, informs me that the horses of Chile, which have lived under nearly the same conditions as their progenitors in Andalusia, remain unaltered, whilst the Pampas horses and the Puno horses are considerably modified. There can be no doubt that horses become greatly reduced in size and altered in appearance by living on mountains and islands; and this apparently is due to want of nutritious or varied food. Every one knows how small and rugged the ponies are on the Northern islands and on the mountains of Europe.

Corsica and Sardinia have their native ponies; and there were,[19] or still are, on some islands on the coast of Virginia, ponies like those of the Shetland Islands, which are believed to have originated through exposure to unfavourable conditions. The Puno ponies, which inhabit the lofty regions of the Cordillera, are, as I hear from Mr. D. Forbes, strange little creatures, very unlike their Spanish progenitors. Further south, in the Falkland Islands, the offspring of the horses imported in 1764 have already so much deteriorated in size[20] and strength that they are unfitted for catching wild cattle with the lasso; so that fresh horses have to be brought for this purpose from La Plata at a great expense. The reduced size of the horses bred on both southern and northern islands, and on several mountain-chains, can hardly have been caused by the cold, as a similar reduction has occurred on the Virginian and Mediterranean islands. The horse can withstand intense cold, for wild troops live on the plains of Siberia under lat. 56°,[21] and aboriginally the horses must have inhabited countries annually covered with snow, for he long retains the instinct of scraping it away to get at the herbage beneath. The wild tarpans in the East have this instinct; and so it is, as I am informed by Admiral Sulivan, with the horses recently and formerly introduced into the Falkland Islands from La Plata, some of which have run wild; this latter fact is remarkable, as the progenitors of these horses could not have followed this instinct during many generations in La Plata. On the other hand, the wild cattle of the Falklands never scrape away the snow, and perish when the ground is long covered. In the northern parts of America the horses descended from those introduced by the Spanish conquerors of Mexico, have the same habit, as have the native bisons, but not so the cattle introduced from Europe.[22] The horse can flourish under intense heat as well as under intense cold, for he is known to come to the highest perfection, though not attaining a large size, in Arabia and northern Africa. Much humidity is apparently more injurious to the horse than heat or cold. In the Falkland Islands, horses suffer much from the dampness; and this circumstance may perhaps partly account for the singular fact that to the eastward of the Bay of Bengal,[23] over an enormous and humid area, in Ava, Pegu, Siam, the Malayan archipelago, the Loo Choo Islands, and a large part of China, no full-sized horse is found. When we advance as far eastward as Japan, the horse reacquires his full size.[24] With most of our domesticated animals, some breeds are kept on account of their curiosity or beauty; but the horse is valued almost solely for its utility. Hence semi-monstrous breeds are not preserved; and probably all the existing breeds have been slowly formed either by the direct action of the conditions of life, or through the selection of individual differences. No doubt semi-monstrous breeds might have been formed: thus Mr. Waterton records[25] the case of a mare which produced successively three foals without tails; so that a tailless race might have been formed like the tailless races of dogs and cats. A Russian breed of horses is said to have curled hair, and Azara[26] relates that in Paraguay horses are occasionally born, but are generally destroyed, with hair like that on the head of a negro; and this peculiarity is transmitted even to half-breeds: it is a curious case of correlation that such horses have short manes and tails, and their hoofs are of a peculiar shape like those of a mule.

It is scarcely possible to doubt that the long-continued selection of qualities serviceable to man has been the chief agent in the formation of the several breeds of the horse. Look at a dray-horse, and see how well adapted he is to draw heavy weights, and how unlike in appearance to any allied wild animal. The English race-horse is known to be derived from the commingled blood of Arabs, Turks, and Barbs; but selection, which was carried on during very early times in England,[27] together with training, have made him a very different animal from his parent-stocks. As a writer in India, who evidently knows the pure Arab well, asks, who now, “looking at our present breed of race-horses, could have conceived that they were the result of the union of the Arab horse and African mare?” The improvement is so marked that in running for the Goodwood Cup the first descendants of Arabian, Turkish, and Persian horses, are allowed a discount of 18 pounds weight; and when both parents are of these countries a discount of 36 pounds.[28] It is notorious that the Arabs have long been as careful about the pedigree of their horses as we are, and this implies great and continued care in breeding. Seeing what has been done in England by careful breeding, can we doubt that the Arabs must likewise have produced during the course of centuries a marked effect on the qualities of their horses? But we may go much farther back in time, for in the Bible we hear of studs carefully kept for breeding, and of horses imported at high prices from various countries.[29] We may therefore conclude that, whether or not the various existing breeds of the horse have proceeded from one or more aboriginal stocks, yet that a great amount of change has resulted from the direct action of the conditions of life, and probably a still greater amount from the long-continued selection by man of slight individual differences.

With several domesticated quadrupeds and birds, certain coloured marks are either strongly inherited or tend to reappear after having been lost for a long time. As this subject will hereafter be seen to be of importance, I will give a full account of the colouring of horses. All English breeds, however unlike in size and appearance, and several of those in India and the Malay archipelago, present a similar range and diversity of colour. The English race-horse, however, is said[30] never to be dun-coloured; but as dun and cream-coloured horses are considered by the Arabs as worthless, “and fit only for Jews to ride,”[31] these tints may have been removed by long-continued selection. Horses of every colour, and of such widely different kinds as dray-horses, cobs, and ponies, are all occasionally dappled,[32] in the same manner as is so conspicuous with grey horses. This fact does not throw any clear light on the colouring of the aboriginal horse, but is a case of analogous variation, for even asses are sometimes dappled, and I have seen, in the British Museum, a hybrid from the ass and zebra dappled on its hinder quarters. By the expression analogous variation (and it is one that I shall often have occasion to use) I mean a variation occurring in a species or variety which resembles a normal character in another and distinct species or variety.

Analogous variations may arise, as will be explained in a future