How Animals Work. 



becomes longer and longer, winding round under the 

 surface of the growing fortress. The tunnels in the 

 fortress are for two distinct purposes : (a) tunnels to 

 eject earth from the nest cavity and bolt run these are 

 generally in the shape of a corkscrew ascending from 

 the nest, and often diverging into blind terminals ; (b) 

 tunnels not connected directly with the nest cavity, but 

 traversing the fortress from runs outside it. Through 

 these tunnels the Mole has brought the earth to heap 

 over the nest, and they seldom occur except in boggy 

 land, where the nest is of necessity near the surface of 

 the ground, or even in the centre of the piled-up mound. 

 The nest cavity is roughly spherical, about the size of 

 a large cottage loaf, and quite smooth from constant 

 friction and use. The nest, which completely fills the 

 nest cavity, is a ball of grass or leaves, or a mixture of 

 both. I have found a nest made entirely of dead beech 

 leaves, others entirely of dead oak leaves ; and when 

 it is remembered that this material must all be brought 

 in by the mouth, the amount of labour Required can 

 be appreciated. When the nest is taken out bodily, it 

 has to be unwound (if made of grass) to find the centre. 

 There is never a hole apparent; and not only is the 

 nest always found closed when the young are within, 

 but in all cases, even when old and long deserted. 

 When dry grass is not obtainable, fresh green grass is 

 used, which soon withers and gets dry with the heat 

 of the Mole's body. When a nest containing young is 

 found, it is invariably infested with fleas and mites. 

 Nearly every fortress has a bolt run, by which the 

 Mole can escape when surprised in the nest. This 

 run leads downwards from the bottom of the nest, and 



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