RATS. 83 



CHAPTER XII. 



RODENTIA RATS. 



THE gnawing-animals, which constitute the order liodentia, form 

 the most sharply defined group of the Mammalia, the distinguish- 

 ing characters and name being derived from their teeth. These 

 are of two kinds only viz., incisors and grinders there being 

 two efficient incisors in each jaw, and from three to six molars. 

 There are no canine teeth at all; consequently it is easy to recog- 

 nize the skull of a rodent by its dentition. The animals are mostly 

 small, the beaver being about the largest; while some kinds of mice 

 are hardly more than a couple of inches long. 



Seven species of rodents have been introduced into this country 

 at one time or another. Of these, three species of rat, the mouse, 

 and the guinea-pig belong to the simple-toothed rodents that is, 

 they never have at any period of their life more than two incisors 

 in the upper jaw. The rabbit and the hare belong to the double- 

 toothed rodents. These have each two large incisors in the upper 

 jaw, and behind them two small almost rudimentary incisors. 



A species of rat was one of the four land-mammals occurring 

 in these islands when Captain Cook first visited New Zealand, the 

 others being a dog and two species of bats. Sir Joseph Banks says 

 in his Journal, (< On every occasion when we landed in this country 

 we have seen, I had almost said, no quadrupeds originally natives 

 of it. Dogs and rats, .indeed, there are the former, as in other 

 countries, companions of men, and the latter probably brought 

 hither by the men. Especially as they are so scarce that I myself 

 have not had an opportunity of seeing even one." 



This was not Forster's experience, for in his account of the 

 second voyage of Cook (in 1773) he says, "Our fellow-voya^vi s 

 [Furneaux in the ' Adventure '] found immense numbers of rats 

 upon the Hippah Rock [Queen Charlotte Sound], so that thi-y 

 were obliged to put some large jars in the ground level with 

 the surface, into which these vermin fell during the night by 



