Mammals in the British Isles. L. Harrison Matthews
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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