488 MURID^— ARVICOLA 



of similar size, and, not being by any means lacking in climbing 

 powers, it regularly takes refuge in the stumps of old willow 

 trees.^ During protracted floods large numbers are sometimes 

 destroyed, but the altered conditions seem never to last long 

 enough to effect the animal's extinction, and its numbers recover 

 in the security of the ponds and ditches and sluggish rivers, 

 which, rather than swift, gravelly streams, are its favourite 

 summer haunts. But it is not tied to these, and when abundant 

 may be found almost anywhere within a reasonable distance of 

 water — in gardens, corn-fields, coastal marshes, hill-streams, 

 or even sand-hills by the sea-shore.^ In the north-western 

 Highlands it frequents the limestone burns, where it takes 

 shelter in holes in the limestone.^ 



It is at all times an expert swimmer and diver, vastly more 

 so, as Mr A. H. Cocks has observed, than the scarcely less 

 aquatic Brown Rat,* but, although it progresses rapidly under 

 the surface, its methods are those of ordinary terrestrial 

 mammals, since it uses all four limbs for purposes of propulsion, 

 and on the surface swims with its head and upper part of its back 

 above the surface. Mr Aubyn Trevor-Battye^ has, however, 

 observed that, when it is not in a hurry, its fore legs may rest 

 at its sides, the hind legs doing all the work.® There is no 

 evidence to show how long it is capable of remaining below the 

 surface. If frightened, it usually contrives to emerge under 

 some cover.' 



Although the young are for some time comparatively help- 

 less, they can swim at an early date, even before their eyes 

 open.^ Monsieur Fernand Lataste has described the first 

 attempts in this direction of a young male of the allied con- 

 tinental Water Rat.® This was taken from its nest before its 



' E. HoUis {MS.) took one from a hole in an oak, 12 feet above the ground. 

 The tree not being hollow, the rat must have climbed up by the outside. 



2 H. A. Macpherson ; W. Evans. 



^ J. A. Harvie-Brown and Macpherson, North-west Highlands, 1904, 42. 



^ Millais (ii., 292) strangely puts the facts in exactly the opposite way. 



^ Pictures in Prose, 1894, 215. 



" Beavers swim with the fore paws motionless under the chin (L. E. Adams). 



' According to Mr Douglas English, Some Smaller British Mammals (undated), 

 if cover is absent, it will bring up a leaf or other material in its mouth from the 

 bottom. 



* H. G. M. Williams, Zoologist, 1857, 5788. " A. sapidus. 



