The origin of British mammals

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THE ORIGIN OF BRITISH MAMMALS

P. A. MORRIS DĂźring the Pleistocene Epoch, popularly known as 'The Ice A g e \ there were at least four separate glacial periods. In between, there were warmer interglacials, when mammals such as the hippopotamus (Hippopotamus amphibiiis) and spotted hyaena (Crocuta crocuta) roamed widely in Britain, just as they do in Africa today. These became extinct as the climate cooled again in the last glaciation. This was not so severe as previous ones and some mammals managed to survive in Britain despite the harsh conditions. When the last glaciation ended, about 10,000 years ago, species that were adapted to cold moved further north, to be replaced by animals from the south. These spread into the areas that are now England, Wales, Ireland and Scotland. They continued to do so as forests began to cover the land - first birch, pine and juniper and later oak and alder as the land became warmer and wetter. This was possible because Britain was still linked to the Continent by low-lying land at that time. Those species that arrived naturally, before Britain and Ireland were cut off from the rest of Europe, are called 'native' species. The first animals to spread would have been those able to withstand cold, such as the fox (Vulpes vulpes), otter (Lutra lutra), stoat (Mustela erminea), mountain hare (Lepus timidus), badger (Meies meles) and red deer (Cervus elaphus). Animals such as bats, hedgehog (Erinaceus europaeus), and weasel (.Mustela nivalis) would have followed as the climate became warmer. Among the last native species to arrive would have been the mole (Talpa europaea) and the red squirrel (Sciurus vulgaris). By about 7,000 BC, the melting of the polar ice cap had liberated enough water to raise the sea level and flood the swampy land between England and the Continental mainland. Britain became an island, and the climate abruptly warmed encouraging the rapid spread of woodland communities here. The only way land animals could now reach Britain was to be brought in by man. Several species, such as the garden dormouse (Eliomys quercinus) and white toothed shrew (Crocidura leucodon) reached northern France only after Britain had been cut off by the sea. Consequently, although they are still found only 35km away across the English Channel, they were never native to Britain. The changing climate caused many species to die out. Later, others that were once common succumbed to competition from our own species and disappeared in comparatively recent times. With the development of farming and Settlements, there was simply no room for them to exist alongside the spreading human population. Bears (Ursus arctos) and wolves (Canis lupus) roamed free in Britain until only a few centuries ago. Wolves survived in England until about 1550, and small numbers were still to be found in Scotland and Ireland in the 1700s. Other large carnivores once native to Britain include the wolverine (Gulo gulo) and lynx (Lynx lynx). They probably became extinct in Britain during the Stone Age, some 5,000 years ago. There has been no evidence of wild beavers (Castor fiber) in Britain

Trans. Suffolk Nat. Soc. 29 (1993)


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The origin of British mammals by Suffolk Naturalists' Society - Issuu