Collins New Naturalist Library. L. Matthews Harrison

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СКАЧАТЬ throughout the British Isles, remains as a truly wild animal only in Scotland, the Lake district, on Exmoor and the Quantock Hills, and in south-west Ireland; elsewhere feral deer, often derived from escaped park animals, are present in many places. In Scotland the deer are animals of the hill, but in lowland England they are more generally inhabitants of woodland where they reach greater size and the stags bear larger antlers.

      The sika deer, C. nippon, smaller than the red deer but similar in build, was introduced from the Far East in the second half of the nineteenth century, and feral populations have become established in a number of places in the British Isles. The coat is red with light spots in summer, darker and unspotted in winter; the rump patch and tail are white except for a narrow black line on the latter. The antlers of the stags are smaller and have fewer tines than those of the red deer, and lack a bez tine between the brow and trez tines. Sika deer inhabit woodlands from which they come out to graze from dusk to dawn. They hybridize freely with red deer where the ranges of the two species overlap.

      The fallow deer, Dama dama, is another introduced species, but has been adopted into our fauna for a much longer time – probably almost a thousand years. It has for long been a favourite ornament in parks from which it has escaped so that feral populations are widespread in England, Wales and Ireland, and are found in some parts of Scotland; those in Epping and the New Forests probably represent the early stock. Bucks stand about three feet high at the withers, does a few inches less; the antlers of the bucks are usually handsomely palmated. The colour varies greatly but is light with spots in summer, much darker and generally without spots in the winter. The border of the white rump patch is black, as is the upper surface of the tail.

      The roe deer, Capreolus capreolus, is a true native of Great Britain but not of Ireland. It is plentiful in Scotland and northern England, but has been introduced into southern England, and into East Anglia where it was exterminated some two hundred years ago. It is a small deer, barely two feet six inches at the withers, with no visible tail. The colour is tawny red, the muzzle black and the chin white; in the darker brown winter coat two white patches appear on the throat. The antlers of the buck are short spikes each with one forwardly directed tine at the base and a backwardly directed one at the top. Roe live in woodlands, which they leave to browse on bushes at dawn and dusk.

      Two other small species of introduced deer are at large in parts of England, descended from animals that escaped from captivity during the present century. The muntjac, Muntiacus reevesi, is widespread through much of south, central and eastern England, and is still increasing its range. It is not more than eighteen inches high at the withers; the coat is deep chestnut in colour, lighter below. The antlers are short spikes carried on long hair-covered pedicles prolonged forward as ribs on the face. Muntjac live in dense cover where they are more easily heard than seen, for they utter a short sharp bark repeated many times when disturbed. The Chinese water deer, Hydropotes inermis, is slightly larger, reddish to greyish brown, and with large ears; the bucks do not have antlers but long upper canine teeth that project from the mouth as tusks nearly three inches in length. Water deer live among long dense herbage on which they graze – they are less widespread than the muntjac, being feral but numerous in parts of Bedfordshire, Northamptonshire, Buckinghamshire, and Huntingdonshire.

       Family Bovidae

      Cattle, sheep and goats do not exist in the wild in the British Isles. Wild cattle, from which domestic cattle are descended, have been extinct in Great Britain for some three thousand years – the ‘wild’ white cattle preserved in several parks are derived from domestic animals. A primitive breed of sheep, the Soay breed, has long been present on the island of the St. Kilda group to which it gives its name meaning ‘Sheep island’; it is derived from domestic stock. The ‘wild’ goats that are feral on mountains or islands in various parts of the British Isles are derived from domestic animals, for the species has never been indigenous. The domestic sheep, however, has played an important part in shaping the ecological background of the British fauna, much of our so-called man-made landscape being in fact a sheep-moulded landscape.

      In the chapters that follow we consider the biology of this mammalian fauna, enquire into its origin and present distribution, and investigate the way of life of its various members, and how it shares the approximately 75 million acres of its homeland with over fifty million human beings.

       CHAPTER 2

       ICE AGES

      THE small number of mammalian species now living in the British Isles is sometimes spoken of as an impoverished fauna. This is not strictly correct; it is a small fauna compared with those of some other lands, but of the forty-six indigenous species only five have been exterminated in historic times, whereas fourteen that are not indigenous have been introduced and now permanently enrich it. The causes of the present composition and distribution of our indigenous mammalian fauna must be sought in the geological history of the islands.

      The basic geological structure of the country has evolved through enormous periods of time during which the rocks were laid down as deposits on the floors of successive seas, or extruded through the earth’s crust by volcanic activity. If we could see from a satellite the events forming the present topography of the earth as in a time-lapse film, so that many millions of years were concentrated into an hour, the tortured crust would appear to be in constant movement, writhing and squirming as immense forces distorted it. The tectonic plates jostling each other or drawing apart to form the oceans, pushed asunder by the material rising between them from below, were sometimes sunk far beneath the sea from which they received deposits of enormous thickness, or thrust up into mountains and lands from which erosion carried their substance back to the oceans – everything was, and still is, in constant flux. During all these upheavals plants and animals were evolving ever since life first appeared on the earth some time in the Precambrian epoch, perhaps as much as three thousand million years ago.

      The successive epochs into which palaeontologists divide geological history each had their characteristic faunas and floras which left their remains as fossils in the rocks, representing a biomass, or aggregate of living matter, so great that it is almost beyond comprehension to the human mind. Among this teeming swarm the mammal-like creatures first appeared in the Triassic epoch, which began some 225 million years ago; but ten million years were to pass before the Eutheria, the placental mammals, evolved towards the end of the Cretaceous epoch. In the succeeding Eocene epoch, which began about seventy million years ago, the orders of mammals that we know as living animals were already differentiated together with others that are now extinct.

      During the following epochs, the Oligocene and the Miocene, in which great crustal disturbance took place, including the upraising of the great mountain ranges, the evolution of the mammals produced a vast variety of forms which reached a peak in numbers before the end of the Miocene some twelve million years ago. In the succeeding Pliocene, which lasted about ten million years, the land masses gradually took on their present shapes, and mammalian species began to decline in number, a decline that continues to the present day. Throughout these epochs the climate varied from time to time, sometimes temperate, at others cool and wet, or warm and arid, but it was not until the Pleistocene that the greatest climatic change in later geological history took place.

      The Pleistocene epoch was comparatively short; it has been deeply studied using modern techniques during the last fifty years so that our knowledge of it increases every day. It was formerly thought to have lasted about a million years, but is now known to have been probably twice as long – some authorities consider it to have lasted as much as three million years. It is popularly called the ‘Ice Age’, a name that over-simplifies the matter, for the ice ebbed and flowed so that mild periods of sometimes almost tropical warmth, separated successive glaciations. At its height ice sheets covered most of Europe, North America and northern СКАЧАТЬ