32 FAUNA OF SHROPSHIRE. 



CHAPTER III. 

 MAMMALS. 



IN considering the animals of an inland County like Shrop- 

 shire, several points are of importance as affecting the 

 whole fauna. In the first place, the County is only an 

 arbitrarily defined portion of a country, and that country an 

 island. The insular position of Great Britain renders it 

 almost impossible for any creatures to reach it from outside 

 unless they can either fly in the air or swim in the sea. Now 

 most Mammals are terrestrial, but one group (the Bats) can 

 fly like birds, while another group (Whales and Seals) can 

 swim. The Bats, however, unlike many birds, do not 

 migrate ; instead of that they hibernate or sleep through the 

 winter. They usually live and seek their food and die in the 

 same district where they were born. The Whales and Seals 

 roam afar in the sea, but rarely ascend rivers far enough to 

 reach so inland a County. Thus it happens that the 

 number of species of Mammals is very limited, and cannot 

 be added to from outside unless by human agency, and any 

 species, once extinct, cannot occur again. For this very 

 reason our Mammals are particularly interesting to the 

 naturalist, and proportionately more space is devoted to 

 them in this volume than to the Birds. This course seems 

 the more necessary because few as they are the number of 

 species is gradually but surely lessening. The Wolf, the 

 Roebuck, and the Wild Boar have been long extinct ; the 

 Black Rat and the Pine Martin disappeared this century ; 

 while the Polecat is on the verge of extinction. It was the 



