184 REPTILES AND FISH 



it will be shown below that Varanus has a profound 

 influence upon the number of crocodiles, yet it is not 

 clear how the reverse can be the case. Varanus seems 

 to enjoy a varied diet. The stomach of one was found 

 to contain two slugs and the shell of an operculate fresh- 

 water mollusc, and collections of shells of the large water 

 snail Ampullaria are often seen on the shore broken on 

 a rock as garden snails are broken by thrushes. ^ 



I have seen a young Varanus biting off the juicy lower 

 part of the stems of rushes ; natives say they eat fish, 

 and on one occasion when my boys were walking a little 

 ahead on the shore, one of them saw an Enswa-swa run 

 away from a piece of dead fish. On one occasion at 

 Jinja a scnall bird that I had shot fell down almost on 

 top of an unperceived Enswa-swa, who at once picked 

 it up and ran away with it, shaking the struggling bird 

 as a terrier shakes a rat. 



The most important food of Varanus, so far as man is 

 concerned, is the egg of the crocodile, and there is no 

 doubt whatever in my mind that the increase of Varanus 

 on the islands since the depopulation must eventually have 

 a powerful effect in reducing the number of crocodiles 

 there. Thus on July 30, 1914, on Tavu Island, two 

 crocodiles' nests previously noted there were found to 

 have been disturbed ; holes had been dug and a crushed 

 egg was lying on the sand. On Bulago Island, on 

 August 1st, two nests previously noted were found 

 ravaged and crushed eggs lay all round. At another point 

 a nest of seventy-six eggs that had been found, freshly laid, 

 on July 24th, had been absolutely cleared out and not 

 one was left. In seven days eggs had been accounted 

 for at the rate of eleven a day, which would seem to be 

 more than one Enswa-swa could accomplish ! In fact, 

 no nest of crocodiles' eggs tvhich I visited a second time 



^ This may, however, be entirely the work of the open-bill stork. See 

 Chapter VIII. 



