The Variation of Animals and Plants under Domestication Volume I Part 4

Soc.' 1861 page 263.) Not only is the face furrowed, but thick folds of skin, which are harder than the other parts, almost like the plates on the Indian rhinoceros, hang about the shoulders and rump. It is coloured black, with white feet, and breeds true. That it has long been domesticated there can be little doubt; and this might have been inferred even from the fact that its young are not longitudinally striped; for this is a character common to all the species included within the genus Sus and the allied genera whilst in their natural state. (3/11. Sclater in 'Proc. Zoolog.

Soc.' February 26, 1861.) Dr. Gray (3/12. 'Proc. Zoolog. Soc.' 1862 page 13. The skull has since been described much more fully by Professor Lucae in a very interesting essay, 'Der Schadel des Maskenschweines' 1870. He confirms the conclusion of von Nathusius on the relations.h.i.+p of this kind of pig.) has described the skull of this animal, which he ranks not only as a distinct species, but places it in a distinct section of the genus.

Nathusius, however, after his careful study of the whole group, states positively ('Schweineschadel' s. 153-158). that the skull in all essential characters closely resembles that of the short-eared Chinese breed of the S. indicus type. Hence Nathusius considers the j.a.pan pig as only a domesticated variety of S. indicus: if this really be the case, it is a wonderful instance of the amount of modification which can be effected under domestication.

Formerly there existed in the central islands of the Pacific Ocean a singular breed of pigs. These are described by the Rev. D. Tyerman and G.

Bennett (3/13. 'Journal of Voyages and Travels from 1821 to 1829' volume 1 page 300.) as of small size, hump-backed, with a disproportionately long head, with short ears turned backwards, with a bushy tail not more than two inches in length, placed as if it grew from the back. Within half a century after the introduction of European and Chinese pigs into these islands, the native breed, according to the above authors, became almost completely lost by being repeatedly crossed with them. Secluded islands, as might have been expected, seem favourable for the production or retention of peculiar breeds; thus, in the Orkney Islands, the hogs have been described as very small, with erect and sharp ears, and "with an appearance altogether different from the hogs brought from the south." (3/14. Rev. G. Low 'Fauna Orcadensis' page 10. See also Dr. Hibbert's account of the pig of the Shetland Islands.)

Seeing how different the Chinese pigs, belonging to the Sus indicus type, are in their osteological characters and in external appearance from the pigs of the S. scrofa type, so that they must be considered specifically distinct, it is a fact well deserving attention, that Chinese and common pigs have been repeatedly crossed in various manners, with unimpaired fertility. One great breeder who had used pure Chinese pigs a.s.sured me that the fertility of the half-breeds inter se and of their recrossed progeny was actually increased; and this is the general belief of agriculturists.

Again, the j.a.pan pig or S. pliciceps of Gray is so distinct in appearance from all common pigs, that it stretches one's belief to the utmost to admit that it is simply a domestic variety; yet this breed has been found perfectly fertile with the Berks.h.i.+re breed; and Mr. Eyton informs me that he paired a half-bred brother and sister and found them quite fertile together.

(FIGURE 3. HEAD OF WILD BOAR, AND OF "GOLDEN DAYS," a pig of the Yorks.h.i.+re Large Breed; the latter from a photograph. (Copied from Sidney's edition of 'The Pig' by Youatt.))

The modification of the skull in the most highly cultivated races is wonderful. To appreciate the amount of change, Nathusius' work, with its excellent figures, should be studied. The whole of the exterior in all its parts has been altered: the hinder surface, instead of sloping backwards, is directed forwards, entailing many changes in other parts; the front of the head is deeply concave; the orbits have a different shape; the auditory meatus has a different direction and shape; the incisors of the upper and lower jaws do not touch each other, and they stand in both jaws beyond the plane of the molars; the canines of the upper jaw stand in front of those of the lower jaw, and this is a remarkable anomaly: the articular surfaces of the occipital condyles are so greatly changed in shape, that, as Nathusius remarks (s. 133), no naturalist, seeing this important part of the skull by itself, would suppose that it belonged to the genus Sus. These and various other modifications, as Nathusius observes, can hardly be considered as monstrosities, for they are not injurious, and are strictly inherited. The whole head is much shortened; thus, whilst in common breeds its length to that of the body is as 1 to 6, in the "cultur-racen" the proportion is as 1 to 9, and even recently as 1 to 11. (3/15. 'Die Racen des Schweines' s. 70.) Figure 3 (3/16. These woodcuts are copied from engravings given in Mr. S. Sidney's excellent edition of 'The Pig' by Youatt 1860. See pages 1, 16, 19.) of the head of a wild boar and of a sow from a photograph of the Yorks.h.i.+re Large Breed, may aid in showing how greatly the head in a highly cultivated race has been modified and shortened.

Nathusius has well discussed the causes of the remarkable changes in the skull and shape of the body which the highly cultivated races have undergone. These modifications occur chiefly in the pure and crossed races of the S. indicus type; but their commencement may be clearly detected in the slightly improved breeds of the S. scrofa type. (3/17.

'Schweineschadel' s. 74, 135.) Nathusius states positively (s. 99, 103), as the result of common experience and of his experiments, that rich and abundant food, given during youth, tends by some direct action to make the head broader and shorter; and that poor food works a contrary result. He lays much stress on the fact that all wild and semi-domesticated pigs, in ploughing up the ground with their muzzles, have, whilst young, to exert the powerful muscles fixed to the hinder part of the head. In highly cultivated races this habit is no longer followed, and consequently the back of the skull becomes modified in shape, entailing other changes in other parts. There can hardly be a doubt that so great a change in habits would affect the skull; but it seems rather doubtful how far this will account for the greatly reduced length of the skull and for its concave front. It is well known (Nathusius himself advancing many cases, s. 104) that there is a strong tendency in many domestic animals--in bull- and pug-dogs, in the niata cattle, in sheep, in Polish fowls, short- faced tumbler pigeons, and in one variety of the carp--for the bones of the face to become greatly shortened. In the case of the dog, as H. Muller has shown, this seems caused by an abnormal state of the primordial cartilage.

We may, however, readily admit that abundant and rich food supplied during many generations would give an inherited tendency to increased size of body, and that, from disuse, the limbs would become finer and shorter.

(3/18. Nathusius 'Die Racen des Schweines' s. 71.) We shall in a future chapter see also that the skull and limbs are apparently in some manner correlated, so that any change in the one tends to affect the other.

Nathusius has remarked, and the observation is an interesting one, that the peculiar form of the skull and body in the most highly cultivated races is not characteristic of any one race, but is common to all when improved up to the same standard. Thus the large-bodied, long-eared, English breeds with a convex back, and the small-bodied, short-eared, Chinese breeds with a concave back, when bred to the same state of perfection, nearly resemble each other in the form of the head and body. This result, it appears, is partly due to similar causes of change acting on the several races, and partly to man breeding the pig for one sole purpose, namely, for the greatest amount of flesh and fat; so that selection has always tended towards one and the same end. With most domestic animals the result of selection has been divergence of character, here it has been convergence.

(3/19. 'Die Racen des Schweines' s. 47. 'Schweineschadel' s. 104. Compare also the figures of the old Irish and the improved Irish breeds in Richardson on 'The Pig' 1847.)

The nature of the food supplied during many generations has apparently affected the length of the intestines; for, according to Cuvier (3/20.

Quoted by Isid. Geoffroy 'Hist. Nat. Gen.' tome 3 page 441.), their length to that of the body in the wild boar is as 9 to 1,--in the common domestic boar as 13.5 to 1,--and in the Siam breed as 16 to 1. In this latter breed the greater length may be due either to descent from a distinct species or to more ancient domestication. The number of mammae vary, as does the period of gestation. The latest authority says (3/21. S. Sidney 'The Pig'

page 61.) that "the period averages from 17 to 20 weeks," but I think there must be some error in this statement: in M. Tessier's observations on 25 sows it varied from 109 to 123 days. The Rev. W.D. Fox has given me ten carefully recorded cases with well-bred pigs, in which the period varied from 101 to 116 days. According to Nathusius the period is shortest in the races which come early to maturity; but the course of their development does not appear to be actually shortened, for the young animal is born, judging from the state of the skull, less fully developed, or in a more embryonic condition (3/22. 'Schweineschadel' s. 2, 20.) than in the case of common swine. In the highly cultivated and early matured races the teeth, also, are developed earlier.

The difference in the number of the vertebrae and ribs in different kinds of pigs, as observed by Mr. Eyton (3/23. 'Proc. Zoolog. Soc.' 1837 page 23.

I have not given the caudal vertebrae, as Mr. Eyton says some might possibly have been lost. I have added together the dorsal and lumbar vertebrae, owing to Prof. Owen's remarks ('Journal Linn. Soc.' volume 2 page 28) on the difference between dorsal and lumbar vertebrae depending only on the development of the ribs. Nevertheless the difference in the number of the ribs in pigs deserves notice. M. Sanson gives the number of lumbar vertebrae in various pigs; 'Comptes Rendus' 93 page 843.), and as given in the following table, has often been quoted. The African sow probably belongs to the S. scrofa type; and Mr. Eyton informs me that, since the publication of this paper, cross-bred animals from the African and English races were found by Lord Hill to be perfectly fertile.

TABLE 2: NUMBER OF VERTEBRAE IN VARIOUS PIGS:

ENGLISH LONG-LEGGED MALE.

Dorsal 15. Lumbar 6. Dorsal plus Lumbar 21. Sacral 5. Total 26.

AFRICAN FEMALE.

Dorsal 13. Lumbar 6. Dorsal plus Lumbar 19. Sacral 5. Total 24.

CHINESE MALE.

Dorsal 15. Lumbar 4. Dorsal plus Lumbar 19. Sacral 4. Total 23.

WILD BOAR FROM CUVIER.

Dorsal 14. Lumbar 5. Dorsal plus Lumbar 19. Sacral 4. Total 23.

FRENCH DOMESTIC BOAR, FROM CUVIER.

Dorsal 14. Lumbar 5. Dorsal plus Lumbar 19. Sacral 4. Total 23.

Some semi-monstrous breeds deserve notice. From the time of Aristotle to the present time solid-hoofed swine have occasionally been observed in various parts of the world. Although this peculiarity is strongly inherited, it is hardly probable that all the animals with solid hoofs have descended from the same parents; it is more probable that the same peculiarity has reappeared at various times and places. Dr. Struthers has lately described and figured (3/24. 'Edinburgh New Philosoph. Journal'

April 1863. See also De Blainville 'Osteographie' page 128 for various authorities on this subject.) the structure of the feet; in both front and hind feet the distal phalanges of the two greater toes are represented by a single, great, hoof-bearing phalanx; and in the front feet, the middle phalanges are represented by a bone which is single towards the lower end, but bears two separate articulations towards the upper end. From other accounts it appears that an intermediate toe is likewise sometimes superadded.

(FIGURE 4. OLD IRISH PIG, with jaw appendages. (Copied from H.D. Richardson on Pigs.))

Another curious anomaly is offered by the appendages, described by M.

Eudes-Deslongchamps as often characterizing the Normandy pigs. These appendages are always attached to the same spot, to the corners of the jaw; they are cylindrical, about three inches in length, covered with bristles, and with a pencil of bristles rising out of a sinus on one side: they have a cartilaginous centre, with two small longitudinal muscles they occur either symmetrically on both sides of the face or on one side alone.

Richardson figures them on the gaunt old "Irish Greyhound pig;" and Nathusius states that they occasionally appear in all the long eared races, but are not strictly inherited, for they occur or fail in animals of the same litter. (3/25. Eudes-Deslongchamps 'Memoires de la Soc. Linn. de Normandie' volume 7 1842 page 41. Richardson 'Pigs, their Origin, etc.'

1847 page 30. Nathusius 'Die Racen des Schweines' 1863 s. 54.) As no wild pigs are known to have a.n.a.logous appendages, we have at present no reason to suppose that their appearance is due to reversion; and if this be so, we are forced to admit that a somewhat complex, though apparently useless, structure may be suddenly developed without the aid of selection.

It is a remarkable fact that the boars of all domesticated breeds have much shorter tusks than wild boars. Many facts show that with many animals the state of the hair is much affected by exposure to, or protection from, climate; and as we see that the state of the hair and teeth are correlated in Turkish dogs (other a.n.a.logous facts will be hereafter given), may we not venture to surmise that the reduction of the tusks in the domestic boar is related to his coat of bristles being diminished from living under shelter?

On the other hand, as we shall immediately see, the tusks and bristles reappear with feral boars, which are no longer protected from the weather.

It is not surprising that the tusks should be more affected than the other teeth; as parts developed to serve as secondary s.e.xual characters are always liable to much variation.

It is a well-known fact that the young of wild European and Indian pigs (3/26. D. Johnson 'Sketches of Indian Field Sports' page 272. Mr. Crawfurd informs me that the same fact holds good with the wild pigs of the Malay peninsula.), for the first six months, are longitudinally banded with light-coloured stripes. This character generally disappears under domestication. The Turkish domestic pigs, however, have striped young, as have those of Westphalia, "whatever may be their hue" (3/27. For Turkish pigs see Desmarest 'Mammalogie' 1820 page 391. For those of Westphalia see Richardson 'Pigs, their Origin, etc.' 1847 page 41.); whether these latter pigs belong to the same curly-haired race as the Turkish swine, I do not know. The pigs which have run wild in Jamaica and the semi-feral pigs of New Granada, both those which are black and those which are black with a white band across the stomach, often extending over the back, have resumed this aboriginal character and produce longitudinally-striped young. This is likewise the case, at least occasionally, with the neglected pigs in the Zambesi settlement on the coast of Africa. (3/28. With respect to the several foregoing and following statements on feral pigs see Roulin in 'Mem. presentes par divers Savans a l'Acad.' etc. Paris tome 6 1835 page 326. It should be observed that his account does not apply to truly feral pigs; but to pigs long introduced into the country and living in a half- wild state. For the truly feral pigs of Jamaica see Gosse 'Sojourn in Jamaica' 1851 page 386; and Col Hamilton Smith in 'Nat. Library' volume 9 page 93. With respect to Africa see Livingstone 'Expedition to the Zambesi'

1865 page 153. The most precise statement with respect to the tusks of the West Indian feral boars is by P. Labat quoted by Roulin; but this author attributes the state of these pigs to descent from a domestic stock which he saw in Spain. Admiral Sulivan, R.N., had ample opportunities of observing the wild pigs on Eagle Islet in the Falklands; and he informs me that they resembled wild boars with bristly ridged backs and large tusks.

The pigs which have run wild in the province of Buenos Ayres (Rengger 'Saugethiere' s. 331) have not reverted to the wild type. De Blainville 'Osteographie' page 132 refers to two skulls of domestic pigs sent from Patagonia by Al. d'Orbigny, and he states that they have the occipital elevation of the wild European boar, but that the head altogether is "plus courte et plus rama.s.see." He refers also to the skin of a feral pig from North America, and says "il ressemble tout a fait a un pet.i.t sanglier, mais il est presque tout noir, et peut-etre un peu plus rama.s.se dans ses formes."

The common belief that all domesticated animals, when they run wild, revert completely to the character of their parent-stock, is chiefly founded, as far as I can discover, on feral pigs. But even in this case the belief is not grounded on sufficient evidence; for the two main types, namely, S.

scrofa and indicus, have not been distinguished. The young, as we have just seen, reacquire their longitudinal stripes, and the boars invariably rea.s.sume their tusks. They revert also in the general shape of their bodies, and in the length of their legs and muzzles, to the state of the wild animal, as might have been expected from the amount of exercise which they are compelled to take in search of food. In Jamaica the feral pigs do not acquire the full size of the European wild boar, "never attaining a greater height than 20 inches at the shoulder." In various countries they rea.s.sume their original bristly covering, but in different degrees, dependent on the climate; thus, according to Roulin, the semi-feral pigs in the hot valleys of New Granada are very scantily clothed; whereas, on the Paramos, at the height of 7000 to 8000 feet, they acquire a thick covering of wool lying under the bristles, like that on the truly wild pigs of France. These pigs on the Paramos are small and stunted. The wild boar of India is said to have the bristles at the end of its tail arranged like the plumes of an arrow, whilst the European boar has a simple tuft; and it is a curious fact that many, but not all, of the feral pigs in Jamaica, derived from a Spanish stock, have a plumed tail. (3/29. Gosse 'Jamaica' page 386 with a quotation from Williamson 'Oriental Field Sports.' Also Col.

Hamilton Smith in 'Naturalist Library' volume 9 page 94.) With respect to colour, feral pigs generally revert to that of the wild boar; but in certain parts of S. America, as we have seen, some of the semi-feral pigs have a curious white band across their stomachs; and in certain other hot places the pigs are red, and this colour has likewise occasionally been observed in the feral pigs of Jamaica. From these several facts we see that with pigs when feral there is a strong tendency to revert to the wild type; but that this tendency is largely governed by the nature of the climate, amount of exercise, and other causes of change to which they have been subjected.

The last point worth notice is that we have unusually good evidence of breeds of pigs now keeping perfectly true, which have been formed by the crossing of several distinct breeds. The Improved Ess.e.x pigs, for instance, breed very true; but there is no doubt that they largely owe their present excellent qualities to crosses originally made by Lord Western with the Neapolitan race, and to subsequent crosses with the Berks.h.i.+re breed (this also having been improved by Neapolitan crosses), and likewise, probably, with the Suss.e.x breed. (3/30. S. Sidney's edition of 'Youatt on the Pig'

1860 pages 7, 26, 27, 29, 30.) In breeds thus formed by complex crosses, the most careful and unremitting selection during many generations has been found to be indispensable. Chiefly in consequence of so much crossing, some well-known breeds have undergone rapid changes; thus, according to Nathusius (3/31. 'Schweineschadel' s 140.), the Berks.h.i.+re breed of 1780 is quite different from that of 1810; and, since this latter period, at least two distinct forms have borne the same name.

CATTLE.

Domestic cattle are certainly the descendants of more than one wild form, in the same manner as has been shown to be the case with our dogs and pigs.

Naturalists have generally made two main divisions of cattle: the humped kinds inhabiting tropical countries, called in India Zebus, to which the specific name of Bos indicus has been given; and the common non-humped cattle, generally included under the name of Bos taurus. The humped cattle were domesticated, as may be seen on the Egyptian monuments, at least as early as the twelfth dynasty, that is 2100 B.C. They differ from common cattle in various osteological characters, even in a greater degree, according to Rutimeyer (3/32. 'Die Fauna der Pfahlbauten' 1861 s. 109, 149, 222. See also Geoffroy Saint-Hilaire in 'Mem. du Mus. d'Hist. Nat.' tome 10 page 172; and his son Isidore in 'Hist. Nat. Gen.' tome 3 page 69. Vasey in his 'Delineations of the Ox Tribe' 1851 page 127, says the zebu has four, and common ox five, sacral vertebrae. Mr. Hodgson found the ribs either thirteen or fourteen in number; see a note in 'Indian Field' 1858 page 62.) than do the fossil and prehistoric European species, namely, Bos primigenius and longifrons, from each other. They differ, also, as Mr.

Blyth (3/33. 'The Indian Field' 1858 page 74 where Mr. Blyth gives his authorities with respect to the feral humped cattle. Pickering also in his 'Races of Man' 1850 page 274 notices the peculiar grunt-like character of the voice of the humped cattle.), who has particularly attended to this subject, remarks, in general configuration, in the shape of their ears, in the point where the dewlap commences, in the typical curvature of their horns, in their manner of carrying their heads when at rest, in their ordinary variations of colour, especially in the frequent presence of "nilgau-like markings on their feet," and "in the one being born with teeth protruding through the jaws, and the other not so." They have different habits, and their voice is entirely different. The humped cattle in India "seldom seek shade, and never go into the water and there stand knee-deep, like the cattle of Europe." They have run wild in parts of Oude and Rohilcund, and can maintain themselves in a region infested by tigers. They have given rise to many races differing greatly in size, in the presence of one or two humps, in length of horns, and other respects. Mr. Blyth sums up emphatically that the humped and humpless cattle must be considered as distinct species. When we consider the number of points in external structure and habits, independently of important osteological differences, in which they differ from each other; and that many of these points are not likely to have been affected by domestication, there can hardly be a doubt, notwithstanding the adverse opinion of some naturalists, that the humped and non-humped cattle must be ranked as specifically distinct.

The European breeds of humpless cattle are numerous. Professor Low enumerates 19 British breeds, only a few of which are identical with those on the Continent. Even the small Channel islands of Guernsey, Jersey, and Alderney possess their own sub-breeds (3/34. Mr. H.E. Marquand in 'The Times' June 23, 1856.); and these again differ from the cattle of the other British islands, such as Anglesea, and the western isles of Scotland.

Desmarest, who paid attention to the subject, describes 15 French races, excluding sub-varieties and those imported from other countries. In other parts of Europe there are several distinct races, such as the pale-coloured Hungarian cattle, with their light and free step, and enormous horns sometimes measuring above five feet from tip to tip (3/35. Vasey 'Delineations of the Ox-Tribe' page 124. Brace 'Hungary' 1851 page 94. The Hungarian cattle descend according to Rutimeyer 'Zahmen Europ. Rindes' 1866 s. 13 from Bos primigenius.): the Podolian cattle also are remarkable from the height of their fore-quarters. In the most recent work on Cattle (3/36.

Moll and Gayot 'La Connaissance Gen. du Boeuf' Paris 1860. Fig. 82 is that of the Podolian breed.), engravings are given of fifty-five European breeds; it is, however, probable that several of these differ very little from each other, or are merely synonyms. It must not be supposed that numerous breeds of cattle exist only in long-civilised countries, for we shall presently see that several kinds are kept by the savages of Southern Africa.

[With respect to the parentage of the several European breeds, we already know much from Nilsson's Memoir (3/37. A translation appeared in three parts in the 'Annals and Mag. of Nat. Hist.' 2nd series volume 4 1849.), and more especially from Rutimeyer's works and those of Boyd Dawkins. Two or three species or forms of Bos, closely allied to still living domestic races, have been found in the more recent tertiary deposits or amongst prehistoric remains in Europe. Following Rutimeyer, we have:-

Bos primigenius.

This magnificent, well known species was domesticated in Switzerland during the Neolithic period; even at this early period it varied a little, having apparently been crossed with other races. Some of the larger races on the Continent, as the Friesland, etc., and the Pembroke race in England, closely resemble in essential structure B. primigenius, and no doubt are its descendants. This is likewise the opinion of Nilsson. Bos primigenius existed as a wild animal in Caesar's time, and is now semi-wild, though much degenerated in size, in the park of Chillingham; for I am informed by Professor Rutimeyer, to whom Lord Tankerville sent a skull, that the Chillingham cattle are less altered from the true primigenius type than any other known breed. (3/38. See also Rutimeyer 'Beitrage pal. Gesch. der Wiederkauer' Basel 1865 s. 54.)

Bos trochoceros.

This form is not included in the three species above mentioned, for it is now considered by Rutimeyer to be the female of an early domesticated form of B. primigenius, and as the progenitor of his frontosus race. I may add that specific names have been given to four other fossil oxen, now believed to be identical with B. primigenius. (3/39. Pictet 'Palaeontologie' tome 1 page 365 2nd edition. With respect to B. trochoceros see Rutimeyer 'Zahmen Europ. Rindes' 1866 s. 26.)

Bos longifrons (or brachyceros) of Owen.

This very distinct species was of small size, and had a short body with fine legs. According to Boyd Dawkins (3/40. W. Boyd Dawkins on the British Fossil Oxen 'Journal of the Geolog. Soc.' August 1867 page 182. Also 'Proc.

Phil. Soc. of Manchester' November 14, 1871 and 'Cave Hunting' 1875 page 27, 138.) it was introduced as a domesticated animal into Britain at a very early period, and supplied food to the Roman legionaries. (3/41. 'British Pleistocene Mammalia' by W.B. Dawkins and W.A. Sandford 1866 page 15.) Some remains have been found in Ireland in certain crannoges, of which the dates are believed to be from 843-933 A.D. (3/42. W.R. Wilde 'An Essay on the Animal Remains, etc. Royal Irish Academy' 1860 page 29. Also 'Proc. of R.