BRITISH MAMMALS 
THE BLACK RAT. 
Mus rattus, Linnaeus. 
Plate 29. 
The so-called ' Black ' Rat is a smaller and less heavily built animal 
than the common Brown Rat, and is characterised by its comparatively 
slender head and body, large shapely ears, and long tail. The measure- 
ments are, head and body about j\ inches, tail about S\, but individuals vary 
a good deal in size. 
This animal, usually known as the ' Old English Black Rat,' has not 
been quite happily named, as the colour can hardly be called black and its 
origin is certainly not English. 
Whence it first came appears uncertain but it probably originated, as a 
more brightly coloured form, in Southern Asia, and travelling westwards by 
degrees, is supposed to have been brought to Europe in the ships of the 
Crusaders during the eleventh and twelfth centuries, where it soon estab- 
lished itself and began to attract attention. 
The species is not mentioned by the ancient Greek or Roman writers. 
In time the colder climate of Europe seems to have changed the 
originally brighter coloration to a much darker hue. 
In England, where this Rat was known as early as the thirteenth century, 
it was not long in becoming a permanent and unwelcome guest, and con- 
tinued as the only British species until the coming of the larger Brown Rat 
[Mus decumanus), early in the eighteenth century. The latter, owing to its 
superior strength, resourceful character, and greater prolificacy, soon ousted 
the weaker race when they came in contact, until the old Black Rat became 
scarce and nearly extinct throughout the greater part of the country, except 
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