7.1.2 Species
It surprises many people to learn that in Britain we have seventy-five species and sub- species of native mammals, a number almost as great as a thousand years ago, for within historical time we have lost only the wolf, the beaver, the wild boar, the brown bear and the reindeer, one fifteenth of the total. Numbers of many species are now much restricted, so is their distribution, and it is possible that some kinds are more wary than in the past, though where sanctuary is given animals soon become easier of approach. Surprise at the number of species comes from the fact that we see so little of most of our mammals as compared with our much richer bird life. Quite half our mammals live a more or less underground existence during the hours of daylight.
Over twenty mammals live in the sea and are not visible except when they come up to breathe–-the whales, dolphins and porpoises–though one who lives by the sea may gain stimulating sidelights on the habits of these creatures.
There are twelve species of bats, all night-flying.   In daytime and in winter the bats roost in belfries and caves and places where the average person does not go, so we know little of this sixth part of our mammalian fauna.
There are many more amateur watchers of birds than of mammals, not only for the reasons just given, but because there are over four hundred species of birds on the British List. Birds are mobile creatures, many being migratory, and lots more visit this country only occasionally
Butterflies, moths and dragon-flies are the most spectacular of the thousands of kinds of insects which populate the earth with us, and because of their visual prominence and beauty they do receive some kindly regard from the citizen. There are only seventy-five British butterflies, several hundreds of moths and a mere handful of dragon-flies.
There are about five thousand beetles in Britain, some useful to husbandry, some harmful, but most of them neutral and living their lives unseen.  Two-winged flies are more numerous and obvious than the beetles and there are nearly as many species. These are the basic food supply of much of our other wild life.
Britain has few reptiles. There is one poisonous snake, the adder, and two harmless ones, the grass snake and the ringed snake. The slow-worm is a legless lizard sometimes mistaken for a snake.
Our amphibians are also few–the frog, two toads and three newts.
All these things are much affected by the results of human activities such as agriculture, fen drainage, and industrial expansion with its consequent pollution of air and water.
Over two thousand species make up the British flora and these again are much at the mercy of man, who does not so much directly destroy as render a habitat untenable for some plants by his varied activities. Many of our rarest and most beautiful plants have little or no place as animal food, but vegetation is at the base of the whole pyramid of wild life. And not only as food : plants show immense variety in type and habitat and provide a large measure of the topography of a countryside. Cover means much in animal life– for the predator catching its quarry, for the quarry hiding from the predator.   It is also a factor ameliorating climate. So man in his control of vegetation wields a fateful sword in the lives of the rest of the animal world.