MISCELLANEOUS NOTES. 665 



was covered with dead and dying rats, sticking in the mud. The people 

 say half of them have died. " Sir Walter Elliot says of the Mettadesthat 

 number perish at the beginning of the rains owing to the cracks filling up 

 their hole or falling in on them. In the monsoon probably large numbers 

 of rats are killed one way or another, but I do not think that when the 

 rains are a failure, that alone is the cause of the plagues. Mr. Sedgwick 

 suggests that ticks have a great deal to do with the keeping of rats in 

 check and the killing off the plagues. They very likely do play a part, but 

 probably the scarcity of food is the principal cause of the plagues, and we 

 know that abundance and scarcity of food has a great deal to do with the 

 facundity of animals. 



All kinds of rats breed chiefly in the spring, though also probably in 

 warm climates, all the year round to a certain extent, and if this spring, 

 when the breeding season commences they cannot get as much food as 

 usual, the litters will be fewer and smaller in size and fewer young rats 

 will reach maturity and take longer before they are able to breed. Rats of 

 all kinds breed when they are a month or two old, but probably owing to 

 the scarcity of food this will be delayed, so that even if this year's rains 

 are good the rat population next winter will be below the average.. With 

 this years supposed good monsoon there will be abundance of food and the 

 rats will breed next spring in numbers and produce by the following winter 

 a regular plague. 



The plagues of rats are said to disappear as quickly as they appear and 

 at times numbers are seen dead in the fields. This points to their having 

 been attacked by some disease which has broken out owing to their great 

 increase in numbers. The natural enemies of rats in ordinary times keep 

 them in check, but when once they become a plague and get beyond their 

 natural enemies then Nature calls in other remedies in the form of some 

 infectious disease. This may account for the quick disappearance 

 of the plagues and for the number of dead rats seen lying about in the 

 fields. 



In all probability a certain number of the rats migrate to a less popu- 

 lated district but of this we know nothing. Any information about rat 

 plagues after a famine would be most acceptable with special reference to 

 the following points : — 



(1) Kind of rat causing plague (skin and skull should be forwarded 



for identification). 



(2) When increase was first noted. 



(3) When rats began to decrease. 



(4) When rats appear to be in their normal numbers again. 



(5) If any great increase or scarcity of birds of prey, mungooses or 



other carnivorous animals also snakes during or before the 

 plague. 



(6) If any dead rats seen lying in the roads and fields (specimens 



should be collected and sent in strong country liquor to the 

 Society.) 



(7) Any signs of rats migrating or leaving the district. 



As regards the preventive measures it is diflicult to say what can be 

 done but it is evident that the sooner measures are adopted the more 

 eriicacious they will be, and with the present scarcity of food it is evident that 

 any method of trapping or poisoning with a bait would be of more value 

 now, than later on when food becomes plentiful. It must be remembered that 

 if a poison is used it must be one which is not harmful to the rats natural 



