Читать книгу Mammals in the British Isles - L. Harrison Matthews - Страница 10
ОглавлениеTHE MAMMALS OF THE BRITISH ISLES
THE number of different kinds of mammal indigenous to the British Isles, and now living in them, is comparatively small. About four thousand kinds of living mammals are known to science throughout the world, but of these only forty-one indigenous land mammals inhabit our region. In addition two kinds of seal breed on our coasts, and seventeen kinds of whale and dolphin are regular inhabitants of our inshore or offshore seas, making a total of sixty.
This total, however, does not include all the kinds of mammal now living in our islands, for we have no less than fourteen kinds that have been introduced by man and have become established members of the fauna. There are moreover two kinds of bat, six kinds of whale or dolphin, and six kinds of seal that have occasionally wandered to our shores and are regarded as accidental vagrants. In addition five kinds of domestic animal have become feral – that is, have run wild – in various parts of the country, and if we add to these four kinds of indigenous mammal that have been exterminated in historic times, and one introduced but subsequently exterminated, we have a grand total of ninety-eight. This represents about one fortieth of the number of known living mammals, far less than the more than five hundred kinds of bird ‘admitted to the British list’, which represent about one fifteenth of the known kinds of bird inhabiting the world.
As might be expected in a country so densely populated by man as the British Isles, most of the mammals are small and inconspicuous so that they easily keep out of harm’s way. The majority are active only by night; those active during the day live concealed underground, in woodland and hedgerow litter, or among dense vegetation. Forty-five different kinds fall into the category of small mammals, ranging in size from the pygmy shrew to the hedgehog and the pine marten; they include the insectivores, the shrews, mole and hedgehog; the bats; all but one of the rodents, the rats, mice and voles; and six of the smaller carnivores such as the stoat, weasel, and polecat.
The medium-sized mammals are much fewer; they range in size from the rabbit to the fox, and include the leporids, the rabbit and hares; four carnivores, the fox, badger, otter and wild cat; one introduced rodent, the coypu; and one introduced marsupial, the red-necked wallaby – only nine different kinds in all. Most of them are nocturnal or crepuscular – active around dusk and dawn – and all but three lie up in underground burrows for much of the daylight hours. The brown hare lies up in a form, a slight depression among herbage or even in a bare ploughed field, in which it is remarkably difficult to detect; if disturbed it escapes from danger by its speed in running and adroitness in jinking if pursued. The mountain hare digs short burrows but usually sits at the entrance and escapes from danger by running away rather than entering the burrow; it too is remarkably inconspicuous when it sits still unless it is in its white winter coat and the ground is not covered with snow. The wallaby lies up in scrubby woodland when not grazing in the open.
Of the large mammals there are only four kinds that are indigenous to our fauna, two kinds of seal and two of deer. To these must be added five introduced kinds of deer, one semi-domesticated; the semiferal horse; and the feral sheep and goat. The only enemy these have to fear is man. The seals avoid him by hauling out only on inaccessible ocean beaches, in sea caves, on remote uninhabited islands of the western coasts, or sandbanks such as those of the Wash where no one can approach unobserved within a mile. The native red deer live in the hills and mountains of the north where there is plenty of room to flee from approaching danger, which they are quick to apprehend by scent, hearing and sight in that order. The native roe deer is a woodland animal, and by day remains hidden in thick cover from which it emerges to feed in the open at dusk and dawn. Where these animals have been introduced to other places, or have become established through escapes from parks and enclosures, they are usually nocturnal inhabitants of woodlands. The introduced fallow, sika, muntjac, and Chinese water deer avoid disturbance by man in a similar way, generally emerging from thick cover only by night or at dawn and dusk. Most of these introductions and escapes have increased greatly in numbers and distribution since the end of the war in 1945, and often live close to human habitations where, because of their secretive habits, they are seldom seen unless specially sought for. Their depredations in field and garden are more commonly seen and noticed with disapproval. The feral, miscalled ‘wild’, horses, goats and sheep live on open moors and mountains where, like the red deer, they can from afar see the approach of danger – that is, man – and can move swiftly away to safety. The feral ponies of the New Forest, however, are so used to the sight of man that they take little notice of his presence, and often approach picnickers to beg for titbits.
The whales and dolphins all fall into the category of large mammals, but as they are creatures of the seas their way of life is so different from that of the land mammals that they cannot usefully be considered as living in the British Isles.
We shall now briefly pass in review the different kinds of mammal, and their taxonomic classification, before going on to consider their habits, habitats and ways of life. We fortunately do not need to enter into minute description of their diagnostic characters and structure, or the basic details of their biology, which are all set forth with great clarity in the second edition of the Handbook of British Mammals, edited for the Mammal Society by G.B. Corbet and H.N. Southern, and published in 1977, a work indispensible to naturalists interested in British Mammals.39
Many naturalists have worked out schemes of classification for animals both before and since the Swedish naturalist Carl von Linné, whose name is latinised as Linnaeus, invented the binomial system. He gave each kind of animal and plant a specific name, and grouped the species, ‘species’ being merely the latin for ‘kind’, that showed some resemblance to each other into genera, singular ‘genus’, the latin for a clan or tribe. For example he classified the rats and mice into the genus Mus, giving the specific names Mus rattus to the black rat, Mus musculus to the house mouse, and Mus sylvaticus to the wood mouse. Since his time they have been separated into different genera, but still retain their specific names.
Before the time of Linnaeus naturalists distinguished species by using cumbrous compound names often amounting to short descriptive sentences. For example, Linnaeus named the daisy of our lawns and fields Bellis perennis, whereas many earlier botanists called it ‘Bellis scapo nudo unifloro’. Early writers in English often used expressions that appear quaint to modern eyes; Edward Topsell whose ‘Historie of Foure-footed Beastes’ was published in 1607–08, heads his chapter on mice ‘Of the vulgar little Mouse’ – meaning the ‘common house mouse’ – to distinguish it from the ‘Vulgar Rat, or great domesticall Mouse’.
When species are classified into genera, the genera themselves need to be arranged into convenient groups, the genera in each having some characters in common. Thus genera are gathered into families, families into orders, orders into classes, and classes into phyla (singular, phylum). Intermediate grades such as superfamily or subfamily are often used for finer divisions of classification. Thus the mammals are put into the Class Mammalia of the sub-phylum Vertebrata of the Phylum Chordata; and the ‘vulgar little mouse’ becomes Mus musculus of the genus Mus, of the Family Muridae, of the Order Rodentia, of the class Mammalia.
Although this system of classification is linear it must not be read as though it were a genealogy or family tree in which the successive levels are the descendants of the previous ones. It is merely a convention and a convenience, at least partly determined by the necessity of representing it in only two dimensions on a written or printed sheet of paper. In nature all the living species of animal are on a single level, and can be likened to the tips of the twigs of a three-dimensional tree, of which the dead-wood in the branches, limbs and trunk represents the extinct ancestors of the living species. The analogy is the more apt because the wood ascends continuously from its origin to its utmost ramifications unlike a family tree which is inverted and where the descent is cut up into generations.
The scheme of classification for the mammals now almost universally accepted and adopted by naturalists was worked out by the American zoologist G.G. Simpson and published in 1945.131 Some minor modifications have been made to it during the last thirty-five years, but it has proved so useful, and is supported by such erudite and convincing arguments, that it has become the standard system adopted by zoologists throughout the world. According to the modified Simpson’s system there are 33 orders of mammals, 14 of which are extinct; 257 families, of which 139 or 54 per cent are extinct; and 2,864 genera, of which 1,932 or 67 per cent are extinct. Thus the living species represent only a small fraction of the total that have lived since the class Mammalia evolved. The diversity and number of species in all the orders except perhaps the rodents reached their peak in the Miocene or Pliocene epochs – some twenty-five to three million years ago – since when they have declined to their present level.
In the British Isles, excluding the whales, we have mammals representing nine of the nineteen orders now living, but of these only seven are indigenous, the two others are either introduced and naturalised, or are derived from stocks of domestic animals. Our fauna is therefore no more than a small sample of the mammalian diversity that ornaments the fauna of the world. It has, moreover, not contained a larger number of orders since the land became generally habitable by warm-blooded animals at the end of the great glaciation of the Pleistocene epoch, about half a million years ago. In the preceeding epochs, before the ice ages, several other orders were represented by species of mammal that became extinct long before the present pattern of the fauna evolved.
Before we discuss the problematic origin of the present fauna we should enumerate and specify the species about which we shall be speaking. In following Simpson’s arrangement of the orders the indigenous species are necessarily not separated from those that have been introduced or are extinct.
ORDER MARSUPIALIA
The marsupials differ so fundamentally from the other mammals that they are placed in a separate Infraclass, the Metatheria, whereas the other mammals of our fauna are included in the Infraclass Eutheria. The marsupials show many unique anatomical characters, but are popularly known merely by a single one, as the mammals that carry their young in a pouch. This is not universally true, for some of them are pouchless; but in all of them the young are born at a comparatively early stage of development and thus need to be carried attached to the mother’s nipples. The marsupials are typically the mammals of the Australasian region, but in addition many species live in South America and one, the Virginian opossum, extends into North America. The living species are divided into eight families of which one, containing the kangaroos and wallabies, is represented in our fauna by a single introduced species.
Family Macropodidae
Macropus rufogriseus, the red-necked wallaby or Bennett’s wallaby, is a medium sized kangaroo-like animal weighing up to about 30 pounds, sometimes nearly 50 pounds. It is native to south-eastern Australia and Tasmania; but as it is easily kept in captivity it is commonly exhibited in zoos and parks of many lands, whence it sometimes escapes. Small feral populations of that origin have become established in Sussex and Derbyshire; smaller colonies deliberately introduced on Herm in the Channel Islands, and on Lambay Island off the coast of Co. Dublin in Eire have died out. Although the English populations have been established for over thirty years they remain small because wallabies are liable to suffer heavy mortality in severe winters.
ORDER INSECTIVORA
The insectivores are mostly small mammals characterised by many primitive or generalised mammalian characters. They are considered to be descended with least change from the ancestral stock of the mammals, though all living species have various specialised adaptations. Insectivores live in most parts of the world except Australasia and South America; they include the tenrecs, hedgehogs, moles, desmans, and shrews.
Family Erinaceidae
Erinaceus europaeus, the hedgehog, our only mammal with prickles in its skin, is the largest of our insectivores. It is present throughout the mainland of Great Britain and Ireland and is common in lowland areas, particularly in the suburbs of towns. It is also found in many of the islands, but has probably been introduced into most of them by man. It lives in woods and hedgerows, coming into the open to feed as night falls. The hedgehog and the dormouse are our only mammals besides the bats that hibernate in winter.
Family Talpidae
Talpa europaea, the mole, is our only mammal that spends nearly all of its life underground. Its cylindrical body, some five to five and a half inches in length, is covered with black velvety fur. The fore limbs and their muscles are highly adapted for tunnelling in the earth, and the strongly clawed hands are broadened internally by an extra bone, the radial sesamoid. The hind feet are similarly but less conspicuously reinforced by an accessory sesamoid bone. The eyes are minute and hidden by the fur, and there is not an ear pinna, but the long snout is plentifully supplied with special touch organs. The sites of mole burrows are shown by the conspicuous heaps of earth pushed up to the surface as the mole digs its underground tunnels, in which it spends most of its life feeding mainly on earthworms which fall into the burrows. Moles are present throughout Great Britain but not Ireland or the Isle of Man; they are not found on many of the smaller islands except Anglesey and the Isle of Wight, Alderney and Jersey.
Family Soricidae
The shrews are small mouse-like animals with velvety fur, long pointed snouts, small eyes and ears. They are insectivorous and carnivorous, generally seeking their food under thick vegetation and litter below which they have runways; some species dig burrows. The first incisor teeth are large and project forwards, acting like forceps in picking up small food objects; the back teeth bear sharp pointed cusps. Shrews need comparatively large quantities of food, and are consequently active by day and night, alternating short periods of activity and rest throughout the twenty-four hours. They soon die of starvation if denied food for a few hours.
The genus Sorex contains two British species, the common shrew, S. araneus, and the pygmy shrew S. minutus, the latter being our smallest British mammal. The enamel of the tips of the teeth is red in both species, which are distinguished by size, relative length of tail which is longer in the pygmy shrew, and colour of the fur, darker in S. araneus but lighter in S. minutus. The common shrew is found throughout England, Scotland and Wales and on many of the islands, but is absent from Ireland, Orkney, Shetland, the outer Hebrides and Man. The pygmy shrew, although less abundant, is found throughout the whole of the British Isles except Shetland, the Scilly and Channel Islands. The common shrew is peculiar in showing chromosome polymorphism, that is, the number and form of the chromosomes differs in animals from different parts of the country.62 Both species are annuals: young born in one summer breed in the next and die in the following autumn, so the winter population consists entirely of immature animals, and none normally lives through a second winter.
The water shrew, N. fodiens, is the only British species of the genus Neomys, and is easily distinguished by its larger size and the black colour of the fur on the upper parts; it too has red-tipped teeth. Although it is aquatic and has fringes of stiff hairs on feet and tail that aid in swimming, it is nevertheless often found at considerable distances from water in woods and hedgerows in similar places to those inhabited by other shrews. It lives in burrows in the banks of clear streams and ponds; when it enters the water the fur traps air so that it appears silvery. The fur nevertheless soon becomes wet and is dried on landing by squeegeeing through the tight fitting burrow. Its food consists of invertebrates and even creatures as large as itself such as frogs and small fish. It is found throughout the mainland but is absent from Ireland, Isle of Man, and the western and northern islands of Scotland. The water shrew is unique among British mammals in being the only one with a poisonous bite, because the submaxillary salivary glands contain a venom that paralyses small prey.
The other two species of British shrew belong to the genus Crocidura, at once distinguished from the rest by their white teeth. Their ears are larger than in the others, and the tails bear a number of long scattered hairs. They are found only in the Scilly and Channel Islands, where they live in habitats similar to those of the common and pygmy shrews. The lesser white-toothed shrew, C. suaveolens, is found on most of the Scilly Islands, Jersey and Sark; it was probably unintentionally introduced into Scilly from the continent by man. The greater white-toothed shrew, C. russula, is found only on Alderney, Guernsey and Herm in the Channel Islands. The water and greater white-toothed shrews reach a life span of eighteen months or a little more, but the lesser white-toothed shrew is as short-lived as the common and pygmy shrews.
ORDER CHIROPTERA – BATS
All the British bats are comparatively small animals, and all are solely insectivorous, and nocturnal or crepuscular. They generally catch their food on the wing but some carry their larger prey to habitual perches to eat it. During darkness they find their prey by echolocation or ‘sonar’, emitting pulses of high frequency ultrasound which are reflected back from surrounding objects to give a mental image probably similar to that produced by sight in other animals. The horseshoe bats emit pulses through the nostrils, the other species through the open mouth. All species hibernate during the winter, and become torpid for four or five months, though not continuously, for hibernation is interrupted by short periods of activity. Bats are long-lived in comparison with other small mammals, reaching an age of four or five, and sometimes over twenty years.
Fig. 1. Side and front views of the head of a horseshoe bat to show the details of the nose-leaf.
Family Rhinolophidae
Two species of this family are members of the British fauna, the greater and lesser horseshoe bats, Rhinolophus ferrumequinum and R. hipposideros. They are characterised by the possession of ‘nose leaves’, thin fleshy outgrowths arising round the nostrils but overlapping the fur of the face with their free outer parts. Their structure is complex and better described by a drawing than by words; the part over the muzzle and round the nostrils is crescentic in shape, hence the English, Latin, and latinised Greek names of these bats.
The nose leaf is part of the special echolocation system. The greater horseshoe bat has a wingspan of 34 to 39 centimetres and is thus one of our larger bats. Its natural roosts are in caves, but it also uses mines and the cellars and roof spaces of buildings. In the British Isles it is found only in southwest England and south Wales. The lesser horseshoe bat is one of our smaller species, with a wingspan of only 22 to 25 centimetres. It roosts in similar places to those used by the larger species, and has a larger range, being found in southwest England, all of Wales and extending into Yorkshire, and far to the west in western Ireland.
Family Vespertilionidae
All the other British bats belong to this family – fifteen species in seven genera. They are mostly small to medium-sized bats but the serotine and noctule equal the greater horseshoe in wingspan, and one, the rare mouse-eared bat exceeds it by up to six centimetres.
Of the fifteen species, six are common throughout much of the British Isles, though only one, the pipistrelle, is found everywhere except in Shetland; they are the whiskered, Natterer’s, Daubenton’s, noctule, pipistrelle, and long-eared bats. Five species are rare, or occasional vagrants – Bechstein’s, the mouse-eared, parti-coloured, Nathusius’ pipistrelle, and the grey long-eared bats. The remaining four species are intermediate, having a limited distribution within the bounds of which they may not be scarce. They are Brandt’s, the serotine, Leisler’s and the barbastelle bats.
Six species of the genus Myotis are British. The whiskered bat, M. mystacinus, is a small dark grey bat that roosts in trees and buildings and often hibernates in caves. It is found throughout England, Wales and Ireland, but is less common in southern Scotland and absent from the north. Brandt’s bat, M. brandti, so closely resembles the whiskered bat that it has only recently been recognised as a separate species, differing slightly in details of the ear and teeth; it is known from many parts of England and Wales but its overall distribution has yet to be ascertained. Natterer’s bat, M. nattereri, is larger, with a wingspan of up to 30 cm, and the fur brown above and light or white below. It can be distinguished from all others by the fringe of stiff short hairs along the edge of the bare skin joining the legs and tail – the interfemoral part of the patagium or double layer of skin that makes a bat in effect an aerofoil. It roosts in trees, buildings and caves throughout the British Isles as far north as central Scotland. Bechstein’s bat, M. bechsteini, very similar to Natterer’s bat but having longer ears and lacking the fringe of hairs on the interfemoral patagium, is a rare woodland bat that has occasionally been found in southern England, mostly in Dorset. The mouse-eared bat, M. myotis, our largest species with wingspan up to 45 centimetres, was known only as a rare vagrant until 1956 when a small colony was found in a cave in Dorset; another was found in Sussex fifteen years later. Daubenton’s bat, M. daubentoni, is medium in size, dark brown above and pale grey below. The ear is comparatively short, and the feet large. It is often seen catching insects flying low over water, but is by no means confined to this way of feeding and frequently hunts in other places. It roosts in hollow trees and buildings, and often hibernates in caves. It is found throughout the British Isles except the northern parts of Scotland and the Hebrides.
Of the genus Vespertilio only the parti-coloured bat, V. murinus, has been found in the British Isles, as a very rare vagrant from the continent. It is a medium-sized bat; the dark brown hairs of the back have white or buff tips which give a grizzled or speckled appearance. Similarly, the genus Eptesicus has only one British species, the serotine bat, E. serotinus, which is, however, a regular though localised member of the fauna. It is a large species with a wingspan of up to 38 centimetres, and has dark brown fur, paler below. It is mainly a woodland species but often roosts in buildings; in England it is found only in the southern and eastern counties as far north as the Wash.
Two species of the genus Nyctalus, the noctule N. noctula, and Leisler’s bat N. leisleri, are widespread though not universal in the British Isles; both have comparatively narrow pointed wings. The large noctule with a wingspan of up to 39 centimetres has dark yellowish or reddish brown fur. It is a woodland bat, roosting in holes in trees, and often flies well before dark, hunting high above the trees. It occurs throughout England and Wales, rarely in southern Scotland and is absent from Ireland. The smaller but similar Leisler’s bat on the other hand is found throughout Ireland but has a more restricted distribution in central and southern England. It, too, is a woodland bat, differing from the noctule not only in its smaller size but also in the colour of the fur on the back, which is reddish brown at the surface but dark brown at the bases of the hairs.
The pipistrelle, Pipistrellus pipistrellus, a small bat with a wingspan not over 25 centimetres, is our commonest species, being found throughout the British Isles with the exception of Shetland. It varies greatly in colour, ranging from rufous through shades of brown to almost black. It roosts commonly in buildings, in which its colonies may number several hundred animals. The closely similar Nathusius’ pipistrelle, P. nathusii, is slightly larger, but is known only as a vagrant, a single specimen having been found in Dorset in 1959.
The barbastelle, Barbastellus barbastellus, the only British member of its genus, is a medium-sized bat with black fur, the lighter tips of the hairs giving a frosted appearance. The ears are short but wide and joined at their bases above the face, thus differing from all other British species except the long-eared bat. Barbastelles roost in hollow trees and buildings, and sometimes hibernate in caves. The species is rather thinly distributed over England and Wales as far north as Cheshire and Yorkshire, and is generally regarded as uncommon.
The long-eared bat, Plecotus auritus, is a small species recognised by its enormously long narrow ears which are nearly as long as the head-and-body. When asleep it tucks the ears under the wings leaving the tragus, the lobe representing the ear-cover, of each side sticking up like a pair of spikey horns. It roosts in trees and buildings and frequently hibernates in caves; when feeding it often hovers to pick insects off the leaves of trees. It is widely distributed throughout the British Isles except in northern Scotland and most of the Scotch islands. The very similar grey long-eared bat, P. austriacus, slightly larger, greyer, and with broader ears, has only recently been recognised as a separate species. It has been found in the south of Dorset, Hampshire and Sussex, but may prove to be more widely distributed after further study.
ORDER LAGOMORPHA
This order contains the rabbits and hares, easily distinguished from rodents by the presence of a second pair of small upper incisor teeth immediately behind the large first pair. There are three British species. Oryctolagus cuniculus, the rabbit, has long been an established member of the fauna although it is not indigenous. It was introduced by man a little before A.D. 1200 from its native Iberian peninsula and north Africa to be raised in confinement for fur and meat; it subsequently escaped, became feral and increased so that it is now found everywhere in the British Isles. The myxomatosis epidemic of the 1950s reduced the population drastically, but numbers have now recovered in many places.
We have two species of hare, the brown hare, Lepus capensis, and the mountain hare, L. timidus, both considerably larger than the rabbit, and with longer, black-tipped ears and longer legs. Linnaeus named the only hare found in Sweden in his time L. timidus, and a species from South Africa L. capensis, not knowing that the brown hare of Europe differs from the mountain hare, or that its range extends from South Africa to most of Europe and much of Asia – hence the peculiarity that our native brown hare takes its scientific name from the Cape of Good Hope. The brown hare, distinguished by the black upper side of the tail, is found throughout England and Wales, southern and north-eastern Scotland. It is not native to Ireland, but has been introduced into the north, and also into many of the Scotch islands. The mountain hare is smaller, has shorter ears, and the upper side of its tail is not black. After the autumn and winter moult the coat is wholly or partly white, and becomes brown again with the spring moult. The mountain hare is indigenous to the highlands of Scotland and all of Ireland. The Irish mountain hare is considered to be a distinct subspecies slightly larger than the Scotch, and assuming a white coat incompletely or not at all during winter. Mountain hares have been introduced into parts of southern Scotland and some of the islands, the Peak district and north Wales.
ORDER RODENTIA
The rodents comprise the rats, mice, squirrels, beavers, porcupines, and cavies. They are mostly small to medium-sized animals, the largest, the Capybara, a huge cavy of South America, reaching a weight of over a hundredweight; few others approach this size. There are about 1,500 species of rodents; Simpson131 remarks that they are ‘believed to be as abundant individually and in variety as all other mammals put together.’ Fortunately we have only fifteen species living in the British Isles, eight of them introduced; one introduced and one indigenous species are extinct. The incisor teeth of rodents, separated by a long gap from the cheek teeth, are single upper and lower pairs with chisel-like cutting edges and long roots from which growth is continuous so that the loss by wear at the cutting edge is perpetually made good.
Family Castoridae
The beaver, Castor fiber, was exterminated in the British Isles about AD 1200, but had been scarce long before. It was abundant in the Fens during prehistoric times.
Family Sciuridae
The red squirrel, Sciurus vulgaris, our only indigenous species, is typically an inhabitant of coniferous forests, especially those of our only indigenous pine, Pinus sylvestris, though not confined to them. The fur is reddish brown above, white below, the tail is long and bushy, and in winter tufts of long hair on the ears are conspicuous. The hairs of the tail and ear tufts wear and bleach during spring and summer, leaving the tail almost white and the ear tufts sparse. The numbers of red squirrels have varied widely during the last 300 years, but reached a peak at the turn of the century since when they have declined again. It is now widespread in much of Scotland, Ireland, Wales and northern England, but extinct in most of southern and central England. The causes of the fluctuation in the size of the population are not known.
The grey squirrel, Sciurus carolinensis, was introduced from North America and irresponsibly released in various places in the last quarter of the nineteenth century and the first of the twentieth. It has spread widely, and is now found in most of England and Wales, central Scotland and central Ireland. It is larger than the red squirrel, and has proportionally larger ears without conspicuous tufts. The fur is grey with yellowish brown streaks on the sides and feet and, in the winter coat, on back and head. The grey squirrel lives in woods of broad-leaved trees as well as of conifers; some town people regard it as an attraction in public parks, but in the country it is so destructive to young trees, fruit, forestry, agriculture and horticulture that it is now illegal to import or to release grey squirrels or keep them in captivity. Legislation, however, came too late to rid us of this pest.
Family Cricetidae
There were five species of voles in the British Isles, one probably introduced, and another that was injudiciously introduced but successfully exterminated. The last was the musk rat, Ondatra zibethicus, which escaped from fur farms, to which it had been brought from its native America. It became established in several districts about 1930, but a great official effort of destruction eliminated it seven years later.
The British voles are small mouse-sized animals with one exception, the water vole, often called the water rat from its larger size. The voles are distinguished from the mice by the rounded or blunt rather than pointed profile of the snout, and the comparatively small ears partly concealed in the fur. The diagnostic character of the different species is given by the pattern of the cheek teeth. Our four species are classified into three genera.
The bank vole, Clethrionomys glareolus, is recognised by the chestnut red fur of the upper side. It lives mostly in woodland, scrub and hedgerows, under which it makes runways and burrows, but it also habitually climbs among the branches of shrubs and small trees – so much that the late Oliver Hook, the well-known naturalist, nicknamed it ‘Cleth the Climber’, though the wood and yellow-necked mice are at some times and in some places equally or even more arboreal111a. The bank vole is often a destructive pest in country gardens. It is found all over the mainland of Great Britain, and on many of the islands, but is not indigenous in Ireland where it has recently been introduced, perhaps by some zoological practical joker, and now occupies a large area in the south-west. Four sub-species are recognised, each confined to a separate island – Raasay, Mull, Skomer, and Jersey. All are larger than the mainland race, and that of Skomer is much brighter in colouration.
The field vole, Microtus agrestis, is of smaller size but has greyish brown fur, smaller ears, and a short tail. It lives mainly in rough grassland and less often among scrub and dense cover; it makes runways and builds its nests under the thick mat of grasses, the stems and leaves of which form the greater part of its food. It is found throughout the mainland of Great Britain and on many of the Hebrides, but not in Ireland, the Isle of Man, Orkney or Shetland.
The voles of Orkney and Guernsey are slightly larger and darker, and differ from the field vole by a detail in the pattern of the cheek teeth. They are a separate species, M. arvalis, common on the Continent whence they were probably accidentally introduced into the islands long ago.
Our largest vole, the water vole Arvicola terrestris, about the size of a rat, lives near rivers, ponds and canals, into the banks of which it burrows to make its nest. Although it feeds mainly upon the grass growing near the banks it readily dives into the water and swims well. Its colour is generally brown, but populations of black water voles are present in north Scotland and East Anglia. The water vole is found throughout the mainland of Great Britain but is rare in north-west Scotland, and is absent from most of the islands and from Ireland. The paradox of a water animal having the scientific name ‘terrestris’ is due to the habits of this vole on the Continent, where it is not confined to the neighbourhood of water.
Family Muridae
The mice and rats differ from the voles in having proportionally larger ears and eyes, more pointed snouts, and longer tails. The cheek teeth differ in having low crowns with cusps. We have three indigenous and one introduced species of mouse, and two introduced rats.
The wood mouse, Apodemus sylvaticus, brownish yellow above and nearly white below, often with a coloured spot on the chest, was formerly called the ‘Long-tailed Field mouse’. It lives wherever there is cover, especially in woodlands and hedgerows and consequently is found throughout the British Isles and off-lying islands into many of which it was probably accidentally introduced by man. A large number of subspecies has been described none of which are now held to be valid. Although primarily vegetarian the diet is very varied and includes many small invertebrates.
A. flavicollis, the yellow-necked mouse, closely resembles the wood mouse but is larger and has a yellow band across the chest joining the colour of the upper side. It is found in many parts of England south of the Humber, and in Wales, but is absent elsewhere. It lives in similar places to the wood mouse, but more frequently comes into houses in autumn and winter. It was not recognised as a member of the British fauna until 1894.
The harvest mouse, Micromys minutus, is the smallest British rodent. Gilbert White of Selborne, the first naturalist to note its presence in England, wrote in 1768152 that he found two of them just counterbalanced ‘one copper halfpenny, which is about the third of an ounce avoirdupois’ or six to the ounce – they must have been thin mice for the average weight is about 6.0 grams or just over four to the ounce. The fur of the upper parts of the harvest mouse is bright reddish yellow and of the underside white. The nose is rather blunt, the hairy ear rather small, and the tail is prehensile. Harvest mice live among tall ground plants such as long grass and rough herbage among the stems of which they climb to seek their food and where they make globular breeding nests in summer up to about two feet above ground; in winter they live among the litter below. They are found, sometimes in abundance, throughout most of England and much of Wales, but are absent from the greater part of Scotland and the whole of Ireland.
The house mouse, Mus domesticus*, has dull brownish grey fur, slightly lighter below, occasionally much lighter. Unlike the other mice it has an unpleasant smell resembling that of acetamide. It is found wherever there are human habitations throughout the British Isles, feeding upon and spoiling man’s stored foods. It also occurs in hedgerows and fields away from buildings. It was introduced from the continent, no doubt unintentionally, about 2,000 years ago. Both the British species of rat are introduced, the ship or black rat about 900, and the brown or common rat about 250 years ago.
The ship rat, Rattus rattus, is commonly black in colour, but also occurs as two other forms, brown with grey underside or brown with nearly white underside. It was once widespread but is now found, with few exceptions, solely in the neighbourhood of sea ports, where it lives only in buildings.
The common rat, Rattus norvegicus, is larger than the ship rat and has comparatively smaller eyes and ears; the fur is greyish brown, lighter beneath. It lives in buildings of all sorts but also inhabits rubbish tips and hedgerows far from them. In addition it commonly lives in the open on the coast, especially on the shores of estuaries and salt marshes. It is found throughout the British Isles and off-lying islands, having replaced the once abundant ship rat. Charles Waterton, the early nineteenth century naturalist of Wakefield, expressed150 his extreme Jacobin loyalty by calling the common rat the ‘Hanoverian rat’ because it was introduced soon after King George I’s accession in 1714 – a name that was sometimes used by other writers.
Family Gliridae
Our only native member of this family is the dormouse, Muscardinus avellanarius, distinguished by its orange-brown fur, long whiskers, and hairy, almost bushy tail. It lives in broad-leaved woodlands, coppices and overgrown hedgerows, building a globular nest of bark fibre, grass, and leaves several feet, sometimes yards, above ground among shrubs. Apart from the bats the dormouse and the hedgehog are the only indigenous British mammals that hibernate; the winter nest is usually made underground or among litter at ground level. The dormouse occurs sparsely throughout England and Wales, becoming scarcer in the north, and is absent from Scotland and Ireland. Another member of the family, the fat dormouse, Glis glis, was introduced at Tring in Hertfordshire in 1902, and has since persisted and spread over a small area of the Chiltern Hills. It closely resembles a small grey squirrel, but has dark rings round the eyes. It inhabits woods, orchards and gardens, and, like the common dormouse, it hibernates, often in the roofs of houses.
Family Hystricidae
The large South American coypu, Myocastor coypus, which produces the fur known commercially as ‘nutria’, escaped from fur farms in the early 1930s and established feral populations in several places, mainly in East Anglia. It is a large aquatic rodent reaching a length of a yard from nose to tail, looking like an enormous brown rat with webbed hind feet, blunt nose, small eyes and ears, and orange coloured enamel on the front of the incisor teeth. In East Anglia the population increased enormously in spite of heavy mortality in severe winters, so that the animals became a pest to agriculture and a threat to the stability of river banks. Since the early 1960s official control measures have greatly reduced its numbers.
ORDER CETACEA
Although seventeen species of whales and dolphins have been recorded as British, mainly because they have been found stranded on our coasts from time to time, they cannot be regarded as part of the British fauna as dealt with here – the wreck of a foreign ship on our coasts does not give its crew British nationality or make it part of the native population.
ORDER CARNIVORA
Of the ten indigenous species of beasts of prey two have been extinct for centuries; the remaining eight have been joined by a recent introduction derived from animals escaped from fur farms.
Family Canidae
The wolf, Canis lupus, was exterminated some 500 years ago in England and Wales, but survived in remote parts of Scotland and Ireland for another 250 years. Its descendent, perhaps with an admixture of other ‘blood’, the domestic dog, has some effect upon the country’s ecology, killing according to one authority146 some 6,000 sheep a year – in 1978 4,639 were killed and 3,833 injured – and every day depositing 500 tons of dung and a million gallons of urine ‘on Britain’s pavements and parks’, equal to the sewage from four million people.
On the other hand the fox, Vulpes vulpes, is found everywhere in Great Britain and Ireland and in some of the islands. Its abundance is due to its adaptability to various habitats and foods, to its nocturnal and crepuscular habits, and to its tolerance of the near neighbourhood of man as shown by its recent extension of habitat into the suburbs of towns.
Family Ursidae
The brown bear, Ursus arctos, has been extinct in the British Isles for a thousand years; its natural distribution covers all of northern Europe, Asia and America. It varies greatly in size, from the comparatively small European race to the enormous ‘grizzlies’ of Kodiak Island off the Alaskan coast, as large as the ‘Cave bear’ that lived in the British Isles before the last glaciation of the Pleistocene epoch.
Family Mustelidae
The family consists of small to medium-sized carnivores, the British species characterised by long bodies and short legs. The pine marten, Martes martes, as large as a rabbit, with deep brown fur, a yellow patch on the throat, and long bushy tail, is an inhabitant of woodlands, where it feeds mainly on small birds and rodents. It is an agile climber. It was formerly found throughout the British Isles but has long been extinct except in northern Scotland, the Lake District, north Wales and Ireland.
Although the pine marten has been successfully destroyed as vermin in most of Great Britain, two other species, the stoat and the weasel, both subjected to similar persecution, have been able to remain plentiful. The larger of the two, the stoat, Mustela erminea, with head and body length of about a foot in males but some two inches shorter in females, is brown above, off-white below, and has a black tip to the tail. In the northern part of its range the winter coat is white with black tail tip; but in the southern part it resembles that of the summer; partly white examples occur in winter between the extremes of its range. Stoats are found throughout the British Isles and on some of the off-lying islands; those in Ireland, being smaller and having less white below, are recognised as a separate subspecies M.e.hibernica.
The weasel, M. nivalis, about four inches shorter than the stoat in both sexes, is similar in colour but does not have a black tail tip. The winter coat is not white in British weasels, though further north on the continent it is. Weasels feed mainly on voles and mice, whereas stoats take larger prey as well, especially rabbits. They are found throughout the mainland of Great Britain and some of the islands, but not in Ireland.
The polecat, M. putorius, is larger than the stoat but similar in build; the fur is brown with a white patch on the face between eyes and ears, the two often joining to form a bar. There is a white patch under the chin extending up onto the muzzle, and the edges of the ears are white. The ferret is a domesticated form of the polecat, perhaps with some hybridisation with the Steppe polecat of eastern Europe which may be specifically different; as it breeds successfully with the polecat, and some specimens cannot be distinguished either by colour or skull structure, the specific name, M. furo, for it seems superfluous. Albino ferrets are popular with the breeders and users of these animals. The polecat is an unselective carnivore; it was exterminated as vermin over most of Great Britain by the beginning of the twentieth century, but remains common in the greater part of Wales and the Welsh Marches.
The mink, M. vison, a native of North America, escaped from fur farms and became established as a feral member of our fauna in the 1950s; it is now widespread in Great Britain and common in many places – it is also present less widely in Ireland. The mink, about the size of a polecat, with a rather bushier tail, has very dark brown fur with white spots on the chin and throat. It is an unselective carnivore, and the effect of its activities on the native fauna has yet to be assessed – it may not be as destructive as some people have feared.
The well-known badger, Meles meles, grey above and black below, with a fore-and-aft black streak over eye and ear on each side of the white head, is found throughout the mainland of the British Isles and on some of the islands, and is common in many parts. It is a comparatively large animal – weights of over 35 pounds have been recorded – and is so widely spread because it is adaptable to many different habitats, has discreetly retiring habits, and is omnivorous, eating anything from earthworms to rabbits and from fruit, bulbs, and nuts to corn and grass. It comes out to forage at night, remaining underground in its set by day.
The otter, Lutra lutra, on the other hand is restricted in habitat to the neighbourhood of water, and, though formerly found throughout the British Isles and the off-lying islands, is consequently much less common than the badger; since about 1950 it has declined greatly in numbers over most of mainland Great Britain, but it is still plentiful in western Scotland, Ireland, much of Wales and south west England. The aquatic habit of the otter is shown by its webbed feet and broad snout with long tactile whiskers. The fur is brown all over, lighter on the throat, and the tail is long and tapering. The diet of the otter consists mainly of fish, freshwater or marine, for in the west of Scotland it is as much an inhabitant of the sea shore as of fresh waters.
Family Felidae
The wild cat, Felis silvestris, somewhat larger than most domestic cats, is a tabby with dark cross stripes on a grey background, and bushy tail ending in a rounded, not pointed, black tip. It has long been extinct in most of Great Britain and is now found mainly in the highlands of Scotland where it is extending into its former range; it was never native to Ireland. Its food includes rabbits, hares, rodents, and birds. It has hybridised much with feral domestic cats – domestic cats both feral and tame are probably the most destructive of all predators to the small mammals and birds of our fauna.
ORDER PINNIPEDIA
The seals are only marginally part of our fauna, for they are confined to the waters off the coast and to the sea shore from which they come a short way onto land only in remote undisturbed islands. They are, however, animals of particular interest to zoologists, and of unusual endearment to the public in general. Two species live and breed on British coasts; five others are merely accidental vagrants from northern seas, and thus form no regular part of our fauna.
Family Phocidae
The common seal, Phoca vitulina, and the grey seal, Halichoerus grypus, are not easy to tell apart when in the water, unless very close to the viewer. The coat colour of both species varies greatly; the basic pattern is of dark spots on a grey background, the spots tending to be smaller in the common seal, but no two individuals are exactly alike. Bull common seals reach a length of two metres overall, cows about 20 cm less, whereas bull grey seals reach three metres but the cows some 45 cm to 60 cm less. The snout of the common seal is comparatively short, giving the head a rounded appearance and a ‘dished’ profile; in the grey seal it is long and high, giving a convex profile to the head. Both species can be found on many parts of our coasts, but concentrate in special places to form breeding colonies. The common seal is least likely to be met with on the southern and western coasts of England and Wales; it breeds at several places on the east coast, especially in the Wash, in Orkney and Shetland, on the west of Scotland and the islands, and the east of northern Ireland. On the east coast of England the main breeding colony of the grey seal is at the Farne islands; in Scotland it abounds in Orkney and Shetland and many islands of the west. There are also breeding colonies on the coasts of Wales, Cornwall, and much of Ireland. The common seal prefers shallow waters with sand and mudbanks and is often found in estuaries, whereas the grey seal lives in deeper waters off rocky coasts. Both species come ashore to give birth, the young of the grey seal remaining on or above the beach for about their first three weeks, but those of the common seal, born on sand or mudbanks covered at high tide, swim with their mothers from the first.
ORDER PERISSODACTYLA
Family Equidae
Wild horses have been extinct in the British Isles for about 10,000 years, but half-wild breeds derived from introduced domestic horses exist in several districts of extensive unenclosed land.
ORDER ARTIODACTYLA
Family Suidae
The wild boar, Sus scrofa, has been extinct in Great Britain for some 300 years. Although its domesticated descendants have played an important part in the rural economy of Ireland it was never indigenous there.
Family Cervidae
Stags of the largest of our two native species of deer, the red deer Cervus elaphus, stand up to about four feet at the withers, hinds about six inches less. The coat colour varies greatly; in general it is red-brown in summer, grey-brown in winter, with a white patch on the rump. Calves at birth are reddish-brown with white spots, but lose the spots at their first moult at the age of about two months. Horns, now generally called antlers, a term originally meaning the branches or tines, are carried only by stags. They are dropped from the pedicles, from which they grow on the forehead, in spring or summer, whereupon new ones at once start growing and are complete by the autumn. The red deer, formerly present 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.
