MAMMALS 



483 



given locality the total number of rabbits may remain practi- 

 cally the same for long periods of time, but, as everyone knows, 

 the introduction of this species into Australia has been followed 

 by an extraordinary increase in numbers, chiefly owing to the 

 absence of predaceous native forms. In respect of fertility the 

 Rabbit is greatly surpassed by some other members of the same 

 order, such as Mice and Voles. Certain species of the latter 

 at times increase at such an alarming rate, both in this country 

 and on the Continent, as to constitute a serious agricultural 

 "plague", to successfully cope with which taxes all the resources 

 of applied science. 



Turning now to 

 the Hare, we find 

 that this animal does 

 not burrow, its home 

 being simply a shel- 

 tered spot known 

 as a "form". The 

 leverets are from two 

 to five in number, 

 their eyes are open 

 from the first, and they are fur-covered when born. After being 

 suckled for about three weeks they have to look after themselves. 



The blind and naked young of the little Harvest- Mouse 

 (Mus minutus, fig. 1000) are born in an elegant globular nest, 

 usually found suspended from the stalks of corn or grass. 

 Gilbert White (in The Natural History of Selborne), in his 

 oft-quoted account of these mice, says that "they build their 

 nests amidst the straws of the corn above the ground, and 

 sometimes in thistles. They breed as many as eight at a litter, 

 in a little round nest composed of the blades of grass or wheat. 

 One of these nests I procured this autumn, most artificially 

 plaited, and composed of the 'blades of wheat, perfectly round, 

 and about the size of a cricket-ball; with the aperture so in- 

 geniously closed, that there was no discovering to what part it 

 belonged. It was so compact and well filled that it would roll 

 across the table without being discomposed, though it contained 

 eight little mice that were naked and blind." 



The Common Squirrel (Sciurus vulgaris] is another nest- 

 building rodent, and constructs its dwelling either in a hole in 



Fig. looo. Harvest-Mice (Mus minutus] and Nest 



