1 3 14 THE RODENTS 



the abundant food soon leads to a prodigious increase in their numbers; but sooner 

 or later they practically exterminate the indigenous inhabitants, and then have to 

 seek a more precarious livelihood by preying upon the crustaceans and mollusks on 

 the shores. Some years ago the number of rats in the slaughter houses around 

 Paris was so great, that as many as 2,650 were killed in a single night, and over 

 16,000 within a month. 



Rats, impelled by scarcity of provisions, at times make migrations in large 

 bodies generally, or always during the night; and on such journeys they will not 

 hesitate to plunge boldly into and swim over such rivers as may come in their way; 

 and it is related that instances have occurred of their being suddenly hemmed in 

 during such voyages by a rapid formation of ice. Some years ago the rats that fre- 

 quented the London Zoological Gardens were in the habit of regularly swimming to 

 and fro across the Regent's canal. When brought to bay, the ferocity with which 

 a rat will defend itself against a human or canine foe, is known to most persons. 

 When pressed by hunger, rats will, however, occasionally attack human beings 

 without provocation; and it is on record that an unfortunate man on entering a coal- 

 pit which had been closed for some time, was actually killed and devoured by a 

 starving host of rats. 



The black rat (Af. rattus) is smaller and more elegantly built than 

 the brown, with a longer and thinner tail; the length of the head and 

 body being about .seven inches, while that of the tail varies from eight to nine 

 inches. Its snout, moreover, is longer and more slender, projecting to a greater 

 distance beyond the lower jaw, while its ears are considerably larger. In Europe 

 the black rat, as its name implies, generally has fur of a deep bluish-black color; but 

 in India and other parts of the east there are varieties, in one of which the tint is 

 usually brown above and white below, while in a second the hue is rufous or yel- 

 lowish brown, and spines are mingled with the fur. When domesticated, white and 

 pied varieties are readily produced, and most of the rats thus colored which are 

 exhibited by showmen, belong to this species. In one of the Indian varieties 

 the length of the head and body is not more than five inches, while in another it 

 reaches eight inches. 



The black rat is very commonly spoken of as the indigenous British 

 Distribution 



d H b't s P ecles I this, however, is incorrect, as this rat was also introduced 



from the East, although at a much earlier date than its brown cousin. 

 The exact date of its arrival in Europe cannot, however, now be determined, 

 although it is known to have existed on the Continent in the thirteenth century. 

 At the present day the European variety of this species is almost cosmopolitan; but 

 the brown and rufous varieties extend from Northern Africa through India to 

 Burma, and are doubtless indigenous to both these regions. 



The black rat, in addition to its inferior size, is a far less ferocious animal than 

 the brown species, which accounts for the ease with which it has been conquered by 

 the latter. In England it is now comparatively rare, the Isle of Dogs being one 

 of its last strongholds; but it is more common in certain parts of the Continent. In 

 Europe its habits are generally very similar to those of the brown rat; but in India 

 it frequently ascends trees, where it makes its nests among the branches, while in 



