Field Guide to the Animals of Britain [antikvár]

-.1 I ¦ |i i : I 1 ¦ I I i ;'. ' ' V,;, I . ' ! M : • V. , ! M, '1 ii M' 1 Vl 1 , ' I , • ' ',1.1 I'H M^'^if ii .1, 1 ^ I , iVî^'i 'm mm Vi'V-lMA: " Understanding animals The Animal Kingdom consists of all living things that are not plants. Although birds, fish and insects are therefore technically animals, in common usage the term is not generally applied to them. This book covers all vertebrate (backboned) animals that live on land in Britain. It therefore includes all four-legged animals and also snakes and slow-worms (which are limbless vertebrates) as well as seals, which spend part of their lives on land and part in water. It does not include vertebrates such as fish and whales, which live entirely in water, nor does it include invertebrate land animals - creatures such as slugs, snails, worms and woodlice, which have no bony skeleton. These are dealt with in companion volumes. The land animals described in this book belong to one or other of three major groups: mammals, amphibians or reptiles, which have each evolved different ways of using energy and reproducing their kind. Mammals (which include man) have hairy or furry bodies and feed their new-bom young on milk. They are described as warm-blooded because their body temperature is normally higher than that of their surroundings - usually within a range of 90-104'F (32-40®C). Because they are able to maintain their own body heat, mammals can be active at any time. Muscle, nerve and digestive action increases at higher temperatures, and animals must have a certain body temperature before the system can be fully active. Amphibians are animals such as frogs, which have soft, moist skins and can breathe air on land or absorb oxygen through the skin when under water. They live in damp places on land, in spring taking wholly to the water for a period in order to breed. They lay eggs that hatch into tadpoles, which live and grow entirely in the water for the first few weeks of life until they are transformed into tiny adults ready for life on land. Reptiles are animals such as snakes, which have dry, scaly skins. They have lungs and breathe air, like mammals, but do not produce milk to feed their young. Some lay eggs and others give birth to live young. Both amphibians and reptiles are 'coldblooded' - that is, their body temperature varies according to that of their surroundings. They are fully active only when outside warmth raises their body temperature to a high enough level, which is generally about 77-90®F (25-32®C). Plant-eating animals are known as herbivores. Some, such as sheep, are totally herbivorous; others will occasionally take different food - grey squirrels, for instance, will take birds' eggs. Animals that feed almost entirely on flesh are described as carnivores, and animals that will feed on plants or flesh as the opportunity offers are called omnivores. Although animals that eat insects are called insectivores, the term can be confusing because all insect-eating animals, bats for example, do not belong to the classification order Insectivora. Animal classification The smallest natural group to which an animal belongs is termed the species. Animals of the same species are able to interbreed and produce fertile offspring. Those of different species do not normally do so. Although an animal's common name usually indicates its species - weasel for example - names can vary in different parts of the country, so animals are given a scientific name based on Latin. The weasel's scientific name is Mustela niualis, of which nivalis is the species name and Mustela the genus name - a name shared by other closely related animals of a different species. So the related stoat is Mustela erminea. When more than one genus closely resembles another, they are grouped together to form a family. The stoat and weasel belong to the Family MusteHdae. Various families are also grouped into related orders. The mustelids all belong to the Order Car-nivora - flesh-eating animals. It is usual for scienrific names to be printed in italic type. The genus name is always given a capital letter, the species name a small letter. With domestic animals such as the cow, there may be many different breeds within a single species; these breeds have been developed by man for particular purposes. A Jersey cow, for example, is a dairy breed developed on Jersey, and looks quite different from a Hereford, developed as a beef breed. Both belong to the same species and have the scientific name Bos (domestic).