LIFE IN WINTER NIGHTS 305 



great extent outbalanced by its sinister responsibility as the 

 principal agent in the dissemination of bubonic plague. It 

 is the chief host of the plague-bearing flea, because it is 

 peculiarly the rat of human habitations in India and China, 

 where plague is most prevalent. But the original source of 

 plague is believed to be a central Asiatic marmot ; and the 

 flea which conveys the infection is known to be harboured by 

 the brown rat also. In the recent cases of plague in Suffolk 

 the evidence strongly pointed to infection having been 

 conveyed by rabbits. If a serious epidemic of plague were 

 to break out in Britain in our own time, it would be much 

 more likely to be disseminated by the brown rat or rabbit, or 

 some of the common voles or mice, than by the scarce black 

 rat. Possibly the future may bring us some new immigrant 

 rodent which will oust the brown rat as effectually as the 

 brown rat has dispossessed the black one. Such a ' super- 

 rat ' would be an absolutely appalling pest to industry and 

 agriculture, and we can only hope that in the development of 

 the brown rat and the occasional local plagues of field and 

 bank voles, the evolution of the rodents has reached its 

 crowning triumphs. 



Even rats have not entire immunity at Nature's hands ; 

 and they pay their own tithes to owls, and foxes, and otters 

 on every winter's night. The chief food of otters is eels ; 

 and it is on them rather than on any kind of fish that they feed 

 at all times of year, and especially in winter. In summer 

 they eat large quantities of frogs ; but this form of diet is cut 

 off in winter, until March wakes the frogs from their lairs in 

 the mud, and sends them swarming to the riverside ditches. 

 Young or weakly rats and water-voles form a considerable 

 minor element in the otter's diet. Barn or white owls kill an 

 enormous number of young and half-grown rats, as well as of 

 mice, voles, and shrews ; and the scarcer long-eared owl is 



