THE WATER RAT 495 



unless enraged by being hurt — makes its entry quite peace- 

 ably, and receives all further captives in a tolerant spirit ; but 

 a freshly caged Water Rat, like a Lemming, expects to be 

 attacked, and generally has a short bout with all its fellow- 

 captives in turn,^ thus indicating that it lives in colonies 

 or pairs each in its own territory apart from its neigh- 

 bours. Of course when the colonies become crowded the 

 sense of "property" indicated above cannot be so readily 

 satisfied, but where the animals are not common, and during 

 the breeding season, they have distinct " beats," as observed on 

 the river Mole, near Reigate, by Mr Adams. These beats 

 extend for about 20 yards along both banks, and the entrance 

 of a stranger is always vigorously resisted, even by immature 

 individuals whose riparian property is invaded. This sense of 

 property rather interferes with the animal's character in 

 captivity, since although naturally gentle and unaggressive, it 

 bites furiously if its nest or its person are interfered with, and 

 cannot be handled unless thoroughly familiar with its owner. 



Although "plagues" of Water Rats are not frequently 

 reported, there is evidence that the numbers of these animals 

 are subject to the same extraordinary fluctuations as those of 

 Grass Mice.^ J. L. Knapp relates' that a large stagnant piece 

 of water was thus suddenly infested one summer with an 

 astonishing number, where none had previously been known ; 

 they disappeared in the following winter. Mr O. V. Aplin 

 commenting* on their varying numbers in Oxfordshire, 

 suggests that many perish during hard winters. Early in 1896 * 

 a serious "plague" was reported from Read's Island, consisting 

 of some 600 acres of reclaimed pasture in the Upper H umber 

 adjoining South Ferriby, Lincolnshire. This is said to have been 

 reduced to the conditions of a rabbit warren by the burrowing 

 propensities of the animals, which were described as "quite 



' Cocks, MS. 



^ As also in Norway, where, however, Collett reports that the increase is chiefly 

 local, and is coincident with that of Microius and Lemmus. In Scotland, also, 

 Service {Annals Scott. Nat. Hist., 1896, 206) noted a marked increase during the 

 "vole plague" of 189 1-3. 



' Journal of a Naturalist, 1829, 142. ■• Zoologist, 1891, 304. 



' SeeR. Payne-Gall wey, Field, 22nd February 1896, 294 ; F. 'Royts, Journ. cit., 

 29'li February 1896, 336 ; also, Eastern Morning News of same date. 



