120 THE REASON WHY! 



; It is not iron bands, nor hundred eyes, 

 Nor brazen walls, nor many wakeful skyes, 

 That can withhold their wilful wandering feet." SPENSER. 



instinct which prompts rats to quit an uninhabited house, and to 

 abandon an unseaworthy ship. 



374. Lemmings are allied to the rat tribes. There are several species of them, 

 varying in size and colour, according to thfl 

 regions they inhabit. They are found in 

 Norway, Lapland, Siberia, and the northern 

 parts of America; those of Norway being 

 nearly the size of the water-rat, and of a 

 tawny colour, variegated with black, the 

 sides of the head and the under parts 

 being white; while those of Lapland and 

 Siberia are scarcely larger than a field- 

 mouse, and much less distinctly marked. 



They subsist entirely on vegetable food ; they form shallow burrows, in 

 the summer time, under the ground, and in winter make long passages under the 

 snow in search of food. Their hairy heads and short ears and tails admirably adapt 

 them for the latter labour. Their migrations are not regularly periodical, but are 

 undertaken at irregular epochs upon an average about once in ten years. 



The inclination, or instinctive faculty, which induces them, with one consent, to 

 assemble from a whole region, collect themselves into an army, and descend from 

 the mountains into the neighbouring plains in the form of a firm phalanx, moving 

 on in a straight line, resolutely surmounting every obstacle, and undismayed by 

 every danger, cannot be contemplated without astonishment. All who have 

 written upon the subject agree that they proceed in a direct course, so that the 

 ground along which they have passed appears at a distance as if it had been 

 ploughed ; the grass being devoured to the very roots in numerous stripes or 

 parallel paths of one or two spans broad, and at the distance of some ells from 

 each other. This army moves chiefly by night, or early in the morning, devouring 

 the herbage as it passes in such a manner that the surface appears to have iJben 

 burnt. No obstacles will materially alter their route ; neither fires, nor deep 

 ravines, torrents, marshes, nor lakes ; they proceed obstinately in a right line, and 

 hence it happens that many thousands perish in the waters, and are found dead by 

 the shores. If a rick of hay or corn occurs in their passage, they eat through it ; but 

 if rocks intervene which they cannot pass, they go round, and then resume their 

 former straight direction. If disturbed or pursued while swimming over a lake, 

 and their phalanx is scattered by oars and poles, they will not recede, but keep 

 swimming directly on, and get into regular order again. Th^y have ever been 

 kiiown to endeavour to board, or pass over a vessel. 



On the passage overland, if attacked by men they will raise themselves up, 

 uttering a kind of barking sound, and fly at the legs of their invaders ; and will 

 fasten so fiercely at the end of a stick as to suffer themselves to be swung about 

 before they quit their hold. Sometimes an intestine war breaks out in these 

 armies during their march, when they fight desperately and destroy 

 each other. 

 On the march they - attacked by various enemies, and particularly by owls 



