Introduction to mammals

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Like ourselves, wild mammals are warm-blooded creatures that bear and suckle live young. The most familiar examples in our countryside are in fact introduced species rather than natives. Grey squirrels were introduced from North America in the 19th century and have displaced their smaller native cousin the red squirrel from most of England and Wales. Rabbits were introduced from Southern Europe centuries earlier.

Two introduced deer are now widespread in Essex as well: the fallow deer from mainland Europe and the muntjac deer from Spain. In some areas they cause serious damage to trees and woodland plants.

Of the native mammals, the most seriously threatened is the water vole, suffering from loss of its bankside habitat and predation by another introduction, the american mink. The dormouse, once to be found in almost every wood and hedgerow, is now restricted to just a few Essex woods.

Otters went extinct in Essex last century but are now making a comeback as the quality of our rivers improves and are spreading south and east into the county along the rivers.

More adaptable small mammals like the common shrew are still widespread, but others like the harvest mouse have been driven out of their former strongholds on farmland and are now largely restricted to places like roadside verges and reedbeds.

The bats are mammals that have taken to the air. Many species have suffered severe declines and all are now protected by law. The most widespread Essex species, and the smallest found in Europe, is the pipistrelle.

© Ken King

More information

"Kingfisher Field Guide to the Mammals of Britain & Europe" by John A. Burton."The Mammals of Essex" by John Dobson (Lopinga Books).