8 The Hawaiian Rat. 



"I have been wondering what the principal food of the rats 

 might be on Popoia. Their habits are difficult to study on account 

 of their extreme shyness. The only knowledge I ever had of their 

 presence was the rapid disappearance of a diminutive brown animal 

 on several occasions, and until I saw them in the trap it would 

 have been impossible to give any adequate description of them. 

 A native who frequently visited Popoia told me that there were no 

 rats there. In dry weather — the greater part of the year — I doubt 

 if the vegetable life would support them. I am inclined to think 

 that the rats depend largely on the food brought in by the petrels, 

 whose burrows they seem to share. The only man whom I have 

 met who has previously seen the Hawaiian rat alive is Mr. Augustus 

 Knudsen of Kauai. He told me some time ago that many years 

 previously he had observed the rats and sea birds living together 

 on the ocean cliffs of Kauai, and that the rats did not appear to 

 disturb the eggs, nor the birds the rats. He had not seen them for 

 many years. 



"Similar conditions undoubtedly exist on Popoia. The oppor- 

 tunities for observation, however, are not the same, as the tern, 

 which is probably what Mr. Knudsen referred to, nests in open, 

 exposed places, and the petrel the exact opposite." 



So much for Mr. Stokes' interesting rediscovery of this sup- 

 posed extinct mammal. The next question is to determine its 

 identity and relationship to other forms. For this purpose the 

 Bishop Museum has very kindly placed all of its material in my 

 hands for study, consisting of the several lots of bones and seven 

 rats in alcohol, three males and four females. 



Two specimens were immediately removed from the alcohol 

 and prepared as skins, the skulls being carefully cleaned. 



The first description of a rat from the Pacific islands is by 

 Titian R. Peale, naturalist of the U. S. Exploring Expedition, 

 who in his report of the birds and mammals obtained by the expedi- 

 tion proposed the name Mus exalans for specimens of native rats 

 obtained on the Dog and Disappointment Islands (Paumotu Archi- 

 pelago), Tahiti, Wake Island (20 west of Marianas, io° north of 

 Marshalls) and Hull's Island (Phoenix Group). 



A specimen from Tahiti, which may be regarded as the type, is 



still preserved in the U. S. National Museum, but lacks the skull. 



[258] 



