NORTH AUSTRALIAN MAMMALIA. 211 



municating burrows in common, but even between different 

 colonies intermigration takes place — in fact, all the animals 

 within a fairly large area seem to form one large family, the 

 members of which are very independent of each other. The 

 " Jalva," of course, must be termed a gregarious animal, but the 

 gregarious disposition of each individual is not in any remark- 

 able degree pronounced. The fact that the animals are living 

 together in colonies may, I think, be better explained by con- 

 sidering that long experience in the course of time has undoubt- 

 edly taught them that it is far easier for ten or perhaps one 

 hundred animals to dig a complicated burrow than for one to 

 do so. 



The day is spent sleeping in the channels of the burrow, and 

 just at sunset or immediately after the "Jalvas" commence 

 to appear outside. Nimbly skipping amongst the sand-heaps 

 and the scanty herbage, the agile animals very soon saunter off 

 in search of food. All night they are roaming about feeding, and, 

 according to my experience, they never drink, at least during the 

 dry season. Their tracks were never seen near any well nor on 

 the shore of the ocean, and, although a watering trough for 

 cattle was situated within two hundred yards of one of the places 

 where I used to procure my specimens, I invariably failed in 

 discovering tracks of the animals at the little pool of water 

 which procured its supply from the leaking trough. 



However crooked and complicated the burrows of the "Jalva" 

 are, still some of their most dangerous enemies are not prevented 

 from intrusion. The large pythons, for instance, Python molurus 

 and Aspidites 7nelanocephalus, frequently visit the colonies in 

 search of prey. I have never caught the pythons in the act of 

 devouring the animals, but the unmistakable large tracks of these 

 snakes — the largest in this locality — were often seen leading in 

 and out through the different holes of the " Jalva" colonies; and 

 the natives unanimously affirmed that the snakes came there to 

 eat the " Jalvas." In the north I have frequently found hair and 

 bones of Petrogale brachyotis in the excrements of large snakes. 



During the long dry season the aborigine is not a very 

 dangerous enemy to the " Jalva," but when the rains set in, and, 

 especially in a heavy wet season, perfectly soak the ground, the 

 burrows collapse. The boggy condition of the earth does not 



