The Variation of Animals and Plants under Domestication Volume I Part 22

EFFECTS OF USE AND DISUSE ON THE LIMB-BONES.

GOOSE, ANCIENTLY DOMESTICATED.

LITTLE VARIATION OF.

SEBASTOPOL BREED.

PEAc.o.c.k, ORIGIN OF BLACK-SHOULDERED BREED.

TURKEY, BREEDS OF.

CROSSED WITH THE UNITED STATES SPECIES.

EFFECTS OF CLIMATE ON.

GUINEA-FOWL, CANARY-BIRD, GOLD-FISH, HIVE-BEES.

SILK-MOTHS, SPECIES AND BREEDS OF.

ANCIENTLY DOMESTICATED.

CARE IN THEIR SELECTION.

DIFFERENCES IN THE DIFFERENT RACES.

IN THE EGG, CATERPILLAR, AND COc.o.o.n STATES.

INHERITANCE OF CHARACTERS.

IMPERFECT WINGS.

LOST INSTINCTS.

CORRELATED CHARACTERS.

I will, as in previous cases, first briefly describe the chief domestic breeds of the duck:--

[BREED 1. COMMON DOMESTIC DUCK.

Varies much in colour and in proportions, and differs in instincts and disposition from the wild duck. There are several sub-breeds:--

1. The Aylesbury, of great size, white, with pale-yellow beak and legs; abdominal dermal sack largely developed.

2. The Rouen, of great size, coloured like the wild duck, with green or mottled beak; dermal sack largely developed.

3. Tufted Duck, with a large top-knot of fine downy feathers, supported on a fleshy ma.s.s, with the skull perforated beneath. The top-knot in a duck which I imported from Holland was two and a half inches in diameter.

4. Labrador (or Canadian, or Buenos Ayres, or East Indian); plumage entirely black; beak broader, relatively to its length, than in the wild duck; eggs slightly tinted with black. This sub-breed perhaps ought to be ranked as a breed; it includes two sub-varieties, one as large as the common domestic duck, which I have kept alive, and the other smaller and often capable of flight. (8/1. 'Poultry Chronicle' 1854 volume 2 page 91 and volume 1 page 330.) I presume it is this latter sub-variety which has been described in France (8/2. Dr. Turral 'Bull. Soc. d'Acclimat.' tome 7 1860 page 541.) as flying well, being rather wild, and when cooked having the flavour of the wild duck; nevertheless this sub-variety is polygamous, like other domesticated ducks and unlike the wild duck. These black Labrador ducks breed true; but a case is given by Dr. Turral of the French sub-variety producing young with some white feathers on the head and neck, and with an ochre-coloured patch on the breast.

BREED 2. HOOK-BILLED DUCK.

This bird presents an extraordinary appearance from the downward curvature of the beak. The head is often tufted. The common colour is white, but some are coloured like wild ducks. It is an ancient breed, having been noticed in 1676. (8/3. Willughby's 'Ornithology' by Ray page 381. This breed is also figured by Albin in 1734 in his 'Nat. Hist. of Birds' volume 2 page 86.) It shows its prolonged domestication by almost incessantly laying eggs, like the fowls which are called everlasting layers. (8/4. F. Cuvier in 'Annales du Museum' tome 9 page 128 says that moulting and incubation alone stops these ducks laying. Mr. B.P. Brent makes a similar remark in the 'Poultry Chronicle' 1855 volume 3 page 512.)

BREED 3. CALL DUCK.

Remarkable from its small size, and from the extraordinary loquacity of the female. Beak short. These birds are either white, or coloured like the wild duck.

BREED 4. PENGUIN DUCK.

This is the most remarkable of all the breeds, and seems to have originated in the Malayan archipelago. It walks with its body extremely erect, and with its thin neck stretched straight upwards. Beak rather short. Tail upturned, including only 18 feathers. Femur and metatarsus elongated.]

Almost all naturalists admit that the several breeds are descended from the common wild duck (Anas boschas); most fanciers, on the other hand, take as usual a very different view. (8/5. Rev. E.S. Dixon 'Ornamental and Domestic Poultry' 1848 page 117. Mr. B.P. Brent in 'Poultry Chronicle' volume 3 1855 page 512.) Unless we deny that domestication, prolonged during centuries, can affect even such unimportant characters as colour, size, and in a slight degree proportional dimensions and mental disposition, there is no reason whatever to doubt that the domestic duck is descended from the common wild species, for the one differs from the other in no important character. We have some historical evidence with respect to the period and progress of the domestication of the duck. It was unknown (8/6. Crawfurd on the 'Relation of Domesticated Animals to Civilisation' read before the Brit. a.s.soc. at Oxford 1860.) to the ancient Egyptians, to the Jews of the Old Testament, and to the Greeks of the Homeric period. About eighteen centuries ago Columella (8/7. Dureau de La Malle in 'Annales des Sciences Nat.' tome 17 page 164; and tome 21 page 55. Rev. E.S. Dixon 'Ornamental Poultry' page 118. Tame ducks were not known in Aristotle's time, as remarked by Volz in his 'Beitrage zur Kulturgeschichte' 1852 s. 78.) and Varro speak of the necessity of keeping ducks in netted enclosures like other wild fowl, so that at this period there was danger of their flying away. Moreover, the plan recommended by Columella to those who wish to increase their stock of ducks, namely, to collect the eggs of the wild bird and to place them under a hen, shows, as Mr. Dixon remarks, "that the duck had not at this time become a naturalised and prolific inmate of the Roman poultry-yard." The origin of the domestic duck from the wild species is recognised in nearly every language of Europe, as Aldrovandi long ago remarked, by the same name being applied to both. The wild duck has a wide range from the Himalayas to North America. It crosses readily with the domestic bird, and the crossed offspring are perfectly fertile.

Both in North America and Europe the wild duck has been found easy to tame and breed. In Sweden this experiment was carefully tried by Tiburtius; he succeeded in rearing wild ducks for three generations, but, though they were treated like common ducks, they did not vary even in a single feather.

The young birds suffered from being allowed to swim about in cold water (8/8. I quote this account from 'Die Enten- und Schwanenzucht' Ulm 1828 s.

143. See Audubon 'Ornithological Biography' volume 3 page 168 on the taming of ducks on the Mississippi. For the same fact in England see Mr. Waterton in Loudon's 'Mag. of Nat. Hist.' volume 8 1835 page 542; and Mr. St. John 'Wild Sports and Nat. Hist. of the Highlands' 1846 page 129.), as is known to be the case, though the fact is a strange one, with the young of the common domestic duck. An accurate and well-known observer in England (8/9.

Mr. E. Hewitt in 'Journal of Horticulture' 1862 page 773; and 1863 page 39.) has described in detail his often repeated and successful experiments in domesticating the wild duck. Young birds are easily reared from eggs hatched under a bantam; but to succeed it is indispensable not to place the eggs of both the wild and tame duck under the same hen, for in this case "the young wild ducks die off, leaving their more hardy brethren in undisturbed possession of their foster-mother's care. The difference of habit at the onset in the newly-hatched ducklings almost entails such a result to a certainty." The wild ducklings were from the first quite tame towards those who took care of them as long as they wore the same clothes, and likewise to the dogs and cats of the house. They would even snap with their beaks at the dogs, and drive them away from any spot which they coveted. But they were much alarmed at strange men and dogs. Differently from what occurred in Sweden, Mr. Hewitt found that his young birds always changed and deteriorated in character in the course of two or three generations; notwithstanding that great care was taken to prevent their crossing with tame ducks. After the third generation his birds lost the elegant carriage of the wild species, and began to acquire the gait of the common duck. They increased in size in each generation, and their legs became less fine. The white collar round the neck of the mallard became broader and less regular, and some of the longer primary wing-feathers became more or less white. When this occurred, Mr. Hewitt destroyed nearly the whole of his stock and procured fresh eggs from wild nests; so that he never bred the same family for more than five or six generations. His birds continued to pair together, and never became polygamous like the common domestic duck. I have given these details, because no other case, as far as I know, has been so carefully recorded by a competent observer of the progress of change in wild birds reared for several generations in a domestic condition.

From these considerations there can hardly be a doubt that the wild duck is the parent of the common domestic kind; nor need we look to other species for the parentage of the more distinct breeds, namely, Penguin, Call, Hook- billed, Tufted, and Labrador ducks. I will not repeat the arguments used in the previous chapters on the improbability of man having in ancient times domesticated several species since become unknown or extinct, though ducks are not readily exterminated in the wild state;--on some of the supposed parent-species having had abnormal characters in comparison with all the other species of the genus, as with Hook-billed and Penguin ducks;--on all the breeds, as far as is known being fertile together (8/10. I have met with several statements on the fertility of the several breeds when crossed. Mr. Yarrell a.s.sured me that Call and common ducks are perfectly fertile together. I crossed Hook-billed and common ducks, and a Penguin and Labrador, and the crossed Ducks were quite fertile, though they were not bred inter se, so that the experiment was not fully tried. Some half-bred Penguins and Labradors were again crossed with Penguins, and subsequently bred by me inter se, and they were extremely fertile.);--on all the breeds having the same general disposition, instinct, etc. But one fact bearing on this question may be noticed: in the great duck family, one species alone, namely, the male of A. boschas, has its four middle tail-feathers curled upwardly; now in every one of the above-named domestic breeds these curled feathers exist, and on the supposition that they are descended from distinct species, we must a.s.sume that man formerly hit upon species all of which had this now unique character. Moreover, sub-varieties of each breed are coloured almost exactly like the wild duck, as I have seen with the largest and smallest breeds, namely Rouens and Call ducks, and, as Mr.

Brent states (8/11. 'Poultry Chronicle' 1855 volume 3 page 512.), is the case with Hook-billed ducks. This gentleman, as he informs me, crossed a white Aylesbury drake and a black Labrador duck, and some of the ducklings as they grew up a.s.sumed the plumage of the wild duck.

With respect to Penguins, I have not seen many specimens, and none were coloured precisely like the wild duck; but Sir James Brooke sent me three skins from Lombok and Bali, in the Malayan archipelago; the two females were paler and more rufous than the wild duck, and the drake differed in having the whole under and upper surface (excepting the neck, tail-coverts, tail, and wings) silver-grey, finely pencilled with dark lines, closely like certain parts of the plumage of the wild mallard. But I found this drake to be identical in every feather with a variety of the common breed procured from a farm-yard in Kent, and I have occasionally elsewhere seen similar specimens. The occurrence of a duck bred under so peculiar a climate as that of the Malayan archipelago, where the wild species does not exist, with exactly the same plumage as may occasionally be seen in our farm-yards, is a fact worth notice. Nevertheless the climate of the Malayan archipelago apparently tends to cause the duck to vary much, for Zollinger (8/12. 'Journal of the Indian Archipelago' volume 5 page 334.), speaking of the Penguin breed, says that in Lombok "there is an unusual and very wonderful variety of ducks." One Penguin drake which I kept alive differed from those of which the skins were sent me from Lombok, in having its breast and back partially coloured with chestnut-brown, thus more closely resembling the Mallard.

From these several facts, more especially from the drakes of all the breeds having curled tail-feathers, and from certain sub-varieties in each breed occasionally resembling in general plumage the wild duck, we may conclude with confidence that all the breeds are descended from A. boschas.

[I will now notice some of the peculiarities characteristic of the several breeds. The eggs vary in colour; some common ducks laying pale-greenish and others quite white eggs. The eggs which are first laid during each season by the black Labrador duck, are tinted black, as if rubbed with ink. A good observer a.s.sured me that one year his ducks of this breed laid almost perfectly white eggs. Another curious case shows what singular variations sometimes occur and are inherited; Mr. Hansell (8/13. 'The Zoologist'

volumes 7, 8 1849-1850 page 2353.) relates that he had a common duck which always laid eggs with the yolk of a dark-brown colour like melted glue; and the young ducks, hatched from these eggs, laid the same kind of eggs, so that the breed had to be destroyed.

(FIGURE 39. SKULLS, viewed laterally, reduced to two-thirds of the natural size. A. Wild Duck. B. Hook-billed Duck.)

The Hook-billed duck is highly remarkable (see figure 39, of skull); and its peculiar beak has been inherited at least since the year 1676. This structure is evidently a.n.a.logous with that described in the Bagadotten carrier pigeon. Mr. Brent (8/14. 'Poultry Chronicle' 1855 volume 3 page 512.) says that, when Hook-billed ducks are crossed with common ducks, "many young ones are produced with the upper mandible shorter than the lower, which not unfrequently causes the death of the bird." With ducks a tuft of feathers on the head is by no means a rare occurrence; namely, in the True-tufted breed, the Hook-billed, the common farm-yard kind, and in a duck having no other peculiarity which was sent to me from the Malayan archipelago. The tuft is only so far interesting as it affects the skull, which is thus rendered slightly more globular, and is perforated by numerous apertures. Call ducks are remarkable from their extraordinary loquacity: the drake only hisses like common drakes; nevertheless, when paired with the common duck, he transmits to his female offspring a strong quacking tendency. This loquacity seems at first a surprising character to have been acquired under domestication. But the voice varies in the different breeds; Mr. Brent (8/15. 'Poultry Chronicle' volume 3 1855 page 312. With respect to Rouens see ditto volume 1 1854 page 167.) says that Hook-billed ducks are very loquacious, and that Rouens utter a "dull, loud, and monotonous cry, easily distinguishable by an experienced ear." As the loquacity of the Call duck is highly serviceable, these birds being used in decoys, this quality may have been increased by selection. For instance, Colonel Hawker says, if young wild ducks cannot be got for a decoy, "by way of make-s.h.i.+ft, SELECT tame birds which are the most clamorous, even if their colour should not be like that of wild ones." (8/16. Col. Hawker 'Instructions to young Sportsmen' quoted by Mr. Dixon in his 'Ornamental Poultry' page 125.) It has been erroneously a.s.serted that Call ducks hatch their eggs in less time than common ducks. (8/17. 'Cottage Gardener' April 9, 1861.)

The Penguin duck is the most remarkable of all the breeds; the thin neck and body are carried erect; the wings are small; the tail is upturned; and the thigh-bones and metatarsi are considerably lengthened in proportion with the same bones in the wild duck. In five specimens examined by me there were only eighteen tail-feathers instead of twenty as in the wild duck; but I have also found only eighteen and nineteen tail-feathers in two Labrador ducks. On the middle toe, in three specimens, there were twenty- seven or twenty-eight scutellae, whereas in two wild ducks there were thirty-one and thirty-two. The Penguin when crossed transmits with much power its peculiar form of body and gait to its offspring; this was manifest with some hybrids raised in the Zoological Gardens between one of these birds and the Egyptian goose (Anser aegyptiacus) (8/18. These hybrids have been described by M. Selys-Longchamps in the 'Bulletins (tome 12 No 10) Acad. Roy. de Bruxelles.'), and likewise with some mongrels which I raised between the Penguin and Labrador duck. I am not much surprised that some writers should maintain that this breed must be descended from an unknown and distinct species; but from the reasons already a.s.signed, it seems to me far more probable that it is the descendant, much modified by domestication under an unnatural climate, of Anas boschas.

OSTEOLOGICAL CHARACTERS.

The skulls of the several breeds differ from each other and from the skull of the wild duck in very little except in the proportional length and curvature of the premaxillaries. These latter bones in the Call duck are short, and a line drawn from their extremities to the summit of the skull is nearly straight, instead of being concave as in the common duck; so that the skull resembles that of a small goose. In the Hook-billed duck (figure 39), these same bones as well as the lower jaw curve downwards in a most remarkable manner, as represented. In the Labrador duck the premaxillaries are rather broader than in the wild duck; and in two skulls of this breed the vertical ridges on each side of the supra-occipital bone are very prominent. In the Penguin the premaxillaries are relatively shorter than in the wild duck; and the inferior points of the paramastoids more prominent.

In a Dutch tufted duck, the skull under the enormous tuft was slightly more globular and was perforated by two large apertures; in this skull the lachrymal bones were produced much further backwards, so as to have a different shape and nearly to touch the post. lat. processes of the frontal bones, thus almost completing the bony orbit of the eye. As the quadrate and pterygoid bones are of such complex shape and stand in relation with so many other bones, I carefully compared them in all the princ.i.p.al breeds; but excepting in size they presented no difference.

(FIGURE 40.-CERVICAL VERTEBRA, of natural size. A. Eighth cervical vertebra of Wild Duck viewed on haemal surface. B. Eighth cervical vertebra of Call Duck, viewed as above. C. Twelfth cervical vertebra of Wild Duck viewed laterally. D. Twelfth cervical vertebra of Aylesbury Duck, viewed laterally.)

VERTEBRAE AND RIBS.

In one skeleton of the Labrador duck there were the usual fifteen cervical vertebrae and the usual nine dorsal vertebrae bearing ribs; in the other skeleton there were fifteen cervical and ten dorsal vertebrae with ribs; nor, as far as could be judged, was this owing merely to a rib having been developed on the first lumbar vertebra; for in both skeletons the lumbar vertebrae agreed perfectly in number, shape, and size with those of the wild duck. In two skeletons of the Call duck there were fifteen cervical and nine dorsal vertebrae; in a third skeleton small ribs were attached to the so-called fifteenth cervical vertebra, making ten pairs of ribs; but these ten ribs do not correspond, or arise from the same vertebra, with the ten in the above-mentioned Labrador duck. In the Call duck, which had small ribs attached to the fifteenth cervical vertebra, the haemal spines of the thirteenth and fourteenth (cervical) and of the seventeenth (dorsal) vertebrae corresponded with the spines on the fourteenth, fifteenth, and eighteenth vertebrae of the wild duck: so that each of these vertebrae had acquired a structure proper to one posterior to it in position. In the eighth cervical vertebra of this same Call duck (figure 40, B), the two branches of the haemal spine stand much closer together than in the wild duck (A), and the descending haemal processes are much shortened. In the Penguin duck the neck from its thinness and erectness falsely appears (as ascertained by measurement) to be much elongated, but the cervical and dorsal vertebrae present no difference; the posterior dorsal vertebrae, however, are more completely anchylosed to the pelvis than in the wild duck. The Aylesbury duck has fifteen cervical and ten dorsal vertebrae furnished with ribs, but the same number of lumbar, sacral, and caudal vertebrae, as far as could be traced, as in the wild duck. The cervical vertebrae in this same duck (figure 40, D) were much broader and thicker relatively to their length than in the wild (C); so much so, that I have thought it worth while to give a sketch of the twelfth cervical vertebra in these two birds. From the foregoing statements we see that the fifteenth cervical vertebra occasionally becomes modified into a dorsal vertebra, and when this occurs all the adjoining vertebrae are modified. We also see that an additional dorsal vertebra bearing a rib is occasionally developed, the number of the cervical and lumbar vertebrae apparently remaining the same as usual.

I examined the bony enlargement of the trachea in the males of the Penguin, Call, Hook-billed, Labrador, and Aylesbury breeds; and in all it was identical in shape.

The PELVIS is remarkably uniform; but in the skeleton of the Hook-billed duck the anterior part is much bowed inwards; in the Aylesbury and some other breeds the ischiadic foramen is less elongated. In the sternum, furculum, coracoids, and scapulae, the differences are so slight and so variable as not to be worth notice, except that in two skeletons of the Penguin duck the terminal portion of the scapula was much attenuated.

In the bones of the leg and wing no modification in shape could be observed. But in the Penguin and Hook-billed ducks, the terminal phalanges of the wing are a little shortened. In the former, the femur, and metatarsus (but not the tibia) are considerably lengthened, relatively to the same bones in the wild duck, and to the wing-bones in both birds. This elongation of the leg-bones could be seen whilst the bird was alive, and is no doubt connected with its peculiar upright manner of walking. In a large Aylesbury duck, on the other hand, the tibia was the only bone of the leg which relatively to the other bones was slightly lengthened.

ON THE EFFECTS OF THE INCREASED AND DECREASED USE OF THE LIMBS.

In all the breeds the bones of the wing (measured separately after having been cleaned) relatively to those of the leg have become slightly shortened, in comparison with the same bones in the wild duck, as may be seen in Table 8.I.

TABLE 8.I.a.

COLUMN 1. Length of Femur, Tibia, and Metatarsus together (inches).

COLUMN 2. Length of Humerus, Radius, and Metacarpus together (inches).