66 BRITISH MAMMALS 



ground. From above this nest cavity start several or many- 

 tunnels into the mound, called the molehill, which is formed by 

 the excavation of the nest. These, it is supposed, are used for 

 ejecting earth from the nest cavity. They are, however, often 

 spiral in their ascent from the nest, with many branches, most of 

 which may end blindly without emergence into the open air. 



In a complicated fortress the design of which is given by Mr. 

 Adams there are as many as eleven exits from the branches of 

 these spiral tunnels into the open air round the base of the mole- 

 hill. Mr. Adams considers that these often very elaborate 

 galleries are simply formed in the process of ejecting the mould 

 from the nest cavity, and are not to be considered as elaborate 

 labyrinths along which the mole may evade rivals or other 

 enemies. Much cleverness is displayed by the moles in exca- 

 vating their fortresses in marshy land or by the banks of streams. 

 A way of escape is always arranged above flood level, which 

 the mole by some inherited instinct or experience seems to 

 be able to gauge pretty correctly. The curious down shafts, 

 ending blindly, which are found in some moles' nests, were 

 thought at one time to be receptacles for paralysed worms which 

 the mole was storing up for food, or a provision for draining the 

 nest in the case of wet weather, or wells which should provide the 

 mole with underground drinking water. All these theories are 

 derided by Mr. Adams, who believes that these down shafts are 

 little else than projected bolt holes which have been abandoned 

 when half made. The bolt hole, or alternative main exit from the 

 nest, is generally started in a downward direction and then turns 

 up somewhat abruptly towards the surface. Sometimes these 

 abandoned pits below the nest do contain bunches of sickly look- 

 ing worms, but these have probably fallen in accidentally. The 

 nest itself, which completely fills the nest cavity, is a ball of 

 grass or leaves, or a mixture of both. There is no hole or 

 entrance to this spherical structure of dried vegetation. When 

 the mole quits it, it manages in some way to arrange the stems of 

 grass or leaves so as not to suggest a passage. Mr. Adams 

 relates that in his experience the inside of the nest is warm to the 



