Meeson. — On a Plague of Rats. 201 



great deal of the more remote country in this district, and has moreovor 

 great natural aptitude and appetite for observing facts in natural history, 

 tells me that he is pretty sure that these rats are the same as he used to 

 see in large numbers many years ago round about Tarndale, — the very dis- 

 trict that our secretary and his party of explorers visited recently. Here, 

 or hereabouts, are the head waters of the Clarence, Awatere, and "Wairau. 

 Of course it would be absurd for me to pretend to fix the precise spot of the 

 original habitat ; but that it was somewhere at the head of the valleys men- 

 tioned, or on the western side of Mount Odin, in the Kaikoura Eange, seems 

 to me indisputable. What other supposition can be entertained ? Consider 

 the geography of the locality in question. It is the north-eastern corner of 

 the island with the waters of Cook Straits and the Pacific washing its coasts 

 on the entire east and norxh. To these shores trend great mountain chains, 

 like the fingers of an enormous stony hand, slightly outstretched from a big 

 central mass more in the interior. Between these chains lie the narrow 

 valleys mentioned above. The rats first appeared on the shores in the 

 north-eastern corner. How did they come there ? No one will contend 

 that they swam across Cook Straits from the North Island, — or that they 

 came from the ocean, or that they journeyed from the middle of the island 

 where, as far as we know, they have not even as yet been seen. Unless, 

 therefore, we assume that they dropped from the skies, or form an illustra- 

 tion, like Van Helmont's mice, of the doctrine of abiogenesis, we are driven 

 to the conclusion that their original habitat was somewhere in the high, 

 rough, and secluded country on the western side of the Kaikoura Eange, 

 whence they descended by one of the narrow valleys that I have referred to. 

 They probably were driven out of their old haunts by the struggle for exist- 

 ence (or subsistence, if you prefer the word), even as in many cases human 

 beings are driven to emigrate ; and, if we enquire what it was that pressed 

 so severely upon the rodents, we shall probably agree that the best explana- 

 tion of the movement en masse is in some exceptional climatic condition. 

 Let it be borne in mind that last summer was very wet, and last winter 

 very cold, the amount of snow lying on the high lands in the interior having 

 been reported from time to time to be exceptionally large. In the month of 

 September 5,000 sheep were at one station alone, in the Kaikoura District, 

 Kekerangu, lost through heavy snow. Under pressure of famine, therefore, 

 the rats, though contented enough with their habitat under ordinary circum- 

 stances, naturally braved new dangers, and made their way to the more 

 fertile and cultivated lower country in the valleys and along the coast, 

 where food would be found more abundantly. Another supposition would 

 be that the struggle for existence arises from excessive increase in numbers, 

 rather than hard winters ; and a third, that the animals are attracted by 



