(68.) Adaptation of the Sheep to Climate.—No animal varies more than the sheep, and none so speedily adapts itself to climate; it would almost appear that nature, convinced of its great utility, had bestowed upon it a constitution so pliant, as to enable it to accommodate itself to any point in a wide scale of temperature; for though its natural situation as a wool-bearing animal, like that of man appears to be the wine countries, yet with him, it has spread to every quarter of the globe, becoming impressed at every change with some peculiarity, alterable only by a change of situation, and varying, we might almost affirm, with the weather; for, where the temperature is equable, there does the animal preserve unchanged an atmospheric stamp, and defies our efforts to alter the breed; while under a fluctuating sky we can model it at will, though in this case, continued exertions are required to secure them for any length of time in an undeviating course.
(69.) Changes produced by Climate.—The wonderful power of temperature in effecting changes upon animals, is well illustrated by the Portuguese, who, after a residence of three hundred years in India, are said to be at present almost as black as Caffres. Bishop Heber, speaking of India, says, "It is remarkable to observe how surely all these classes of men (whites—Persians, Greeks, Tartars, Turks, and Arabians), in a few generations, even without any inter-marriage with the Hindoos, assume the deep olive tint, little less dark than a negro, which seems natural to the climate." Buchanan also in his travels through the same country, alludes to a tribe of black Jews who have, in all probability, been settled in the district ever since the period of the captivity under Nebuchadnezzar, 3000 years ago, and who retain all the national peculiarities of their race, with the exception of their colour, which is now as dark as that of the surrounding tribes. These examples, however, it may be affirmed, are not to the point, as embracing theories in regard to peculiar changes in an animal different from the sheep, but such objections are perfectly groundless, as what will affect colour in mankind, will lead to changes even of a more wonderful nature in the sheep, seeing that it is abandoned more entirely to such an influence.
(70.) Temperature preferred by Sheep.—Sheep, though capable of thriving in a great variety of climates, seem to prefer such as are temperate, and in these only do they arrive at perfection. They are common on the Cordilleras at an elevation of from 3300 to 8200 feet, within which limits they propagate readily without any care; but the reverse is the case in hotter regions, it being difficult to rear lambs in the plains of Meta, and no sheep are to be met with from the river to the foot of the Cordilleras, though their skins, from being in demand for making parchment, sell as high as those of the ox. Sheep were at one time, according to Thunberg, the scarcest articles in Batavia, as their woolly coat rendered the heat of the climate quite insupportable; but this inconvenience was at last remedied by sending them, on their arrival from the Cape, further up the country, to the Blue Mountains, where the air is several degrees colder. The question then naturally occurs, if an elevation of temperature is, as in this instance, fatal to these animals, how do they happen to have spread over a vast tract of country in spite of such extremes? Simply for the reason, that when an animal is left to the exercise of its own free will, and the dominion of its instincts, it will not subject itself to the danger of an extreme in any thing. It will not traverse several hundred miles in a single season, and thus expose itself to sudden changes. The natural dispersion of all animals is gradual, so that their constitutions are enabled, from the slowness of the transition, to accommodate themselves, by an alteration in covering and habit, to surrounding circumstances, which would, were the variations abrupt, speedily destroy it. The reason why a race of animals occasionally thrives so well in a country to which it may be removed, appears to lie in its being suited, I may say, accidentally, by peculiar conformation, to the temperature to which it is transplanted. There are some happy climates where, introduce what animals you will, no matter how stunted they are, or how different the degree of warmth may be, their offspring will thrive, proving large and vigorous, and every way worthy of being placed at the head of its species. These are, however, cases where the transition is from an extreme of heat or cold to a temperate atmosphere. Witness what Mr Dawson, the manager of the Australian Agricultural Company, says in his private journal (quoted in Cunningham's New South Wales). "Both the climate and the soil appear by nature intended to produce fine wool, and fine animals too, even from the worst beginnings. The latter seems a paradox. The extensive range afforded to every animal keeps it in good condition, and, perhaps, the natural grasses may have more of good in them than their appearance indicates. However this may be, the climate clearly has a wonderful effect on the size of all animals, even upon man, who is universally tall here, though born of diminutive parents. From this I am led to believe, that the climate governs chiefly, and thus every breeding animal introduced here will attain a size not known in Europe."
(71.) Extent of the Alterations produced by Climate.—Changes occasioned by climate are always limited to the fleece, horns, and disposal of the fat, and never extend to those parts, on the permanence of which the animal depends for its station in the scale of being, as the feet, teeth, and digestive organs. In tropical countries we find the fleece approaching more to hair than wool, as in the sheep of Thibet, so celebrated for the silky nature of their coat. Burchell remarks, that the skins he brought from the Cape of Good Hope were often taken for those of an unknown quadruped, from the furry nature of their wool, if such it can be called, and thinks it is owing as much to the pasture, which is well adapted for giving these animals a soft and useful fur, though not suited, like New South Wales, for the growth of the finest wool, and that the colony might turn this to great advantage. In cold regions the hairy covering is more developed and fully coarser, but always mingled with a proportion of hard rough wool. The influence of climate on portions of the fleece and skin is well illustrated by circumstances which have occurred in Galloway, even within the limits of our traditionary writings.[ [11] The native sheep of the Highlands of that district is supposed to have been a small, handsome, white-faced breed; at least so thinks John MacLellan, who wrote an account of Galloway in 1650, from the wool being much praised, and eagerly bought up by merchants, which would not have been the case if taken from the black-faced animal; yet how happens it that at present the native breed exists only in the lower parts of Kirkcudbrightshire, the high country exhibiting black-faced sheep, which, after every trial, have been found best adapted to the climate, and pasture of the moors and Highlands; while Chalmers owns that it has not been ascertained when or whence this hardy breed were brought to their present locality? Why, it is tolerably plain, that though the white-faced sheep might be placed there originally, yet they would speedily lose every trace of their origin, and become black-faced when placed on a hilly country, and subjected to the slow but certain influence of peculiar food and climate.
Mr Culley imagines, that the dun-faced sheep were the earliest tenants of the Scottish hills, but so far as my researches extend, that supposition is entirely contradicted. Chalmers remarks, that the black-faced animals superseded the goats, which were at one time a source of subsistence to the farmers, and it is exceedingly probable, that as the old white-faced began to change their appearance, and became gradually able to withstand the rigours of a mountain fare, and winter under a dun skin, and short rough wool, so would they recommend themselves as the best of all stock to the hard-driven agriculturalist.
(72.) Increase of the Number of the Horns.—As much wonder is sure to be excited by the fact, that bony prominences are subjected with as great certainty to the modelling hand of climate as softer parts, I give the following from a recent work, entitled, "Gardens and Menagerie of the Zoological Society Delineated," premising, however, that, in my opinion, temperature has a vast deal more to do with alterations in the horns than domestication or cultivation. "One of the most curious modifications produced by cultivation in the domesticated sheep consists in the augmentation of the number of its horns; two, three, or even four supplementary appendages of this description being occasionally produced in addition to the normal number. Under these circumstances the additional horns usually occupy the upper and fore part of the head, and are of a more slender shape, and take a more upright direction than the others, thus approaching in character to those of the goats, while the true horns retain more or less of the spiral curve that distinguishes those of the sheep. There exists a strong tendency to the propagation of this monstrosity, which is extremely frequent in the Asiatic races, but is also met with in a breed that is common in the north of Europe, and is said to have been originally derived from Iceland, and the Feroe Islands. In this case it is unconnected with any other anomaly, but in the flocks of the nomad hordes of Tartary, it is usually combined with an enlargement of the tail, and adjacent parts, by the deposition of fat, frequently to an enormous extent."
(73.) Causes of the various forms of the Horn.—Horns are seldom met with in the sheep of hot climates, occurring more frequently in cold and temperate regions; thus following closely the development of the other coverings, to which, as before stated (19), they are strictly analogous. The fleece consists of two portions—hair and wool, the one predominating more or less over the other, as the climate may direct. The form of the horns is always in unison with the character of the fleece: thus, if the animal is covered with hair, as in the goat, the horns will be straight; but if it is clothed with wool, as in the sheep, the horns will be curved. The same holds good in other animals. The reason of this appears to lie in the tendency which the hair or wool, constituting the horny sheath, has to model the form of the supporting bone. The fibre of hair is nearly straight; that of wool is, on the other hand, remarkable for the number of tufted curls, or small spiral ringlets, into which it naturally contracts; so that a Merino ram, for example, will never be found with rectilinear horns, nor a true goat with twisted ones. The truth of these remarks is borne out by observations on animals on whose heads more than two horns are occasionally met with. We always in such instances notice, that the additional horns are straight, thus indicating the presence of a considerable quantity of hair among the wool. The curve will be more decided, and the twists more numerous, in proportion as the fibre comes nearer and nearer to a perfect wool—evidence of which we have in the beautifully-tufted and spiral horns of the Merino ram, which are as opposite in this respect to those of the goat, as is its fleece to the hairy coat of the latter. From these considerations I am led to believe, that the form of the horn, when present, is an excellent guide to the nature and quality of the other coverings, and an index to every gradation which can possibly occur between wool and hair.
(74.) The proper Temperature required for Sheep.—Regular warmth is absolutely necessary for the production of a good animal and a fine fleece, and is only to be obtained by attending to the draining and clearing of land, so as to dissipate moisture, and allow currents of air to play freely across the country.[ [12] An atmosphere which holds suspended a large quantity of watery vapour, is always extremely chilling to an animal body. This is accounted for by the well-known fact, that a moist air, being a better conductor of caloric than a dry one, robs an animal more quickly of heat. Thus, in passing from the dry air of the hills into the vapour of the valleys in a winter morning, we feel as if the transition had been from a temperate to an icy region. Hence one of the reasons why sheep thrive best in a rather elevated situation. Moist air, however, is exceedingly oppressive in hot weather, because evaporation, from the surface of the body, is to a great extent diminished; and it is only by the perspiration being allowed to escape rapidly, and to convey away the heated particles, that we can manage to be in any degree comfortable during the heat of summer. This free evaporation we endeavour in every way to obtain, and often in a manner that ignorant people would consider as the reverse of sensible. It is well known that draughts of cold liquids are very far from answering the purpose of lowering our temperature when above a pleasant standard; but we find that a basin of hot soup, or tea, will speedily bring about the desired end, by producing a copious determination of fluid to the skin. Yet, if the air contained no moisture, we should experience sensations just as unpleasant as those already mentioned; for evaporation from our bodies would proceed at such a rate, that we would soon be parched. It is to counteract this tendency of dry air that the Americans are in the habit of placing a small vessel of water on their stoves, by which contrivance a quantity of vapour is diffused through the apartment, sufficient to balance the loss from the arid warmth of the fire.
That an equable temperature is only to be obtained by draining and clearing a marshy and wooded country, is sufficiently authenticated. In the thickly wooded and swampy territories of Guiana, rain falls continually during nearly eight months of the year; and the cold is so intense, that fires are necessary in the houses throughout the night. But in Cayenne and its neighbourhood, which were cleared of wood about one hundred and fifty years ago, the increase of temperature is now so great, that during the night the people are annoyed by the warmth, and the rains are neither so frequent nor so heavy as in the rest of the country. Paris and Quebec are nearly under the same latitude; yet the air of the latter is much colder than that of the former, evidently from its being surrounded by forests so dense and umbrageous, that sun and wind are alike denied access to the earth. The difference between a cleared and an uncleared country, in regard to wool, is well illustrated, by contrasting North America, its heavy woods and stagnant atmosphere, with the thinly timbered surface and constantly renovated air of New South Wales. It is only within the last few years that Canada has been enabled to compete with Britain in the article of wool, and that the sheep, which were of the coarsest kind, have been so improved as to do away with the prejudices against their mutton. Australia, on the other hand, has, from its earliest colonization, figured as a sheep-rearing country of the first importance; and nothing has conduced so much to this as its freedom from closely planted trees, by the absence of which the settler is enabled at once to stock his farm with the best of sheep. Nature, in fact, could never have intended sheep to pasture in a wooded country, as is clearly evinced by their coat, to which every thing in the shape of bush or tree is in the highest degree inimical.
(75.) Geographical limits of the Sheep.—Every plant and animal has certain geographical limits, out of which it cannot exist. With the exception of man and the dog, no animal has a wider range than the sheep, extending as it does from Iceland almost to the equator, and from a few degrees south of that to the polar extremity of South America. But though existing under so great a variety of exposures, it must not be inferred that it can come to perfection in them all. On the contrary, it rather delights in the temperate zones, and can evidently only be raised to its highest point of excellence in the countries of the vine. The western parts of continents produce better sheep than the eastern, and the southern hemisphere better than the northern; as in the former situations the temperature is more nearly equable than in the latter. The same may be said of maritime districts, as compared with such as are inland. Temperature is affected in the same way by elevation as by northern or southern position—the mean heat diminishing in the same ratio when ascending a mountain, as in receding from the equator. On this account, Humboldt compared the earth to two mountains with their bases at the equator, and their summits at the poles. The mean temperature, when resulting from the height of the place above the level of the sea, is at the same time influenced by the nature of the aspect, as we notice in the Alps, where the Glacier exists on the northern side, at the same elevation at which the vineyard yields a perfect fruit upon the southern.