28 INTRODUCTION 



settling down to the water surface. Others alter their beats 

 but little throughout the year, but none is more regular than the 

 Pipistrelle — which may be encountered night after night on the 

 same restricted course. 



On the whole the food appears to consist of such insects as 

 may happen to be caught ; the choice depending, perhaps, 

 rather on the strata of the air in which insects are flying than 

 on any preference for particular kinds. The high flight of the 

 Noctule and its size seem to bring it largely into contact with 

 the large strong-flying beetles which the Greater Horseshoe 

 seems to catch before they have risen to high altitudes. The 

 smaller bats probably rely on flies and small moths for the chief 

 part of their sustenance. The resort of the Water Bat leads it 

 to capture caddis-flies, but for the remaining species there is no 

 observed differentiation. In captivity practically all insects are 

 accepted except those which are distasteful to insectivorous 

 animals generally. Messrs E. L. Rollinat and R. Trouessart' 

 find that whereas the Mouse-eared, Natterer's, and Daubenton's 

 Bats devour cockroaches with avidity, the Serotine, Pipistrelle, 

 Long-eared, Barbastelle, and Notch-eared show no marked 

 predilection for them. Bats in general are extremely voracious, 

 and their powers of consuming insects will be alluded to in 

 connection with their habits in confinement. 



Bats are thirsty creatures and love to lick up water or 

 milk. In nature they often drink, like swallows,^ on the wing, 

 and, although there is no reason to suppose that, like the 

 birds, they seek to wash themselves in the water, they have 

 been occasionally detected alighting on its surface,' and on 

 such occasions have surprised the observer by the agility with 

 which they rowed themselves along with flapping wings, or at 

 will resumed their flight. A Long-ear has been observed 

 settling by some water to drink. 



As is well known, bats afford a conspicuous instance of 

 the phenomenon of hibernation, on which subject the brilliant 

 researches of the Italian Lazarre Spallanzani,* although under- 

 taken over one hundred years ago, are still fascinating reading. 



1 op. cit. infra, p. 32. 2 As noticed by Gilbert White. 



3 J. G. Millais; C. M. Smith, Field, 20th July 1889, 97 ; Lord Lilford, Zoologist, 

 1887, 66 {M. mystacinus). * Op. cit. infra, p. 30. 



