98 ANIMAL LIFE OF THE BRITISH ISLES. 



originated in Trans-Baikal, whence it has spread westwards, even 

 to America by way of the British Isles. Both species hit upon 

 an improved method of extending their range over the earth. 

 The old-fashioned natural way for mammals to spread was for 

 a few adventurous individuals to make food-finding excursions 

 beyond the district in which they were born ; but climate, 

 mountain ranges, broad rivers or seas often checked further 

 progress. The Rats discovered that by keeping close to man 

 they were always in the neighbourhood of food, whether 

 intended for himself or his domestic animals ; and even these 

 tame creatures would at times serve for the Rats' meals. So 

 when they found man loading ships with grain and other 

 desirable food they decided to go with him. Often they con- 

 trived to get into his bales of merchandise and so conveyed to 

 the hold. If not, there were always mooring ropes which 

 served as bridges from the quay to the vessel. And so they got 

 themselves conveyed in comfort, sure that wherever the goods 

 went there would be settlements of their biped friends to house 

 them and serve their ends generally. Now, wherever man has 

 established himself, you are almost certain that the Rat is close 

 at hand. 



Mr. A. W. Rees, in his interesting " Creatures 'of the Night, : ' 

 has summarised the chief characteristics of this species in a 

 paragraph. He says : " Brown Rats are an insufferable nuisance. 

 There is no courtesy or kindness in the nature of the Rat ; no 

 nesting bird is safe from his attacks, unless her home is beyond 

 his reach in some cleft of a rock that he cannot scale or in some 

 fork of a tree that he cannot climb. He is a cannibal even 

 the young and the sick of his own kind become the victims of 

 his rapacious hunger and he will eat almost anything, living 

 or dead, from the refuse in a garbage heap to the dainty egg of 

 a willow-wren in the tiny, domed nest amid the briars at the 

 margin of the river." 



As compared with the Black Rat he is more heavily built, 



