THE HIPPOPOTAMUS 293 



further study will no doubt reveal characters by which 

 several races may be recognized of this wide-spread species. 



The hippo often wanders far overland at night, and 

 doubtless thus wandered by day in the past ages before 

 man became the most formidable foe of all big creatures. 

 In consequence it is found in some land-locked waters, like 

 Lake Naivasha, to which it can only have penetrated by 

 extensive journeys across country containing no streams in 

 which it could swim or hide itself. Where human beings 

 are rare and relatively inoffensive, it is often found in 

 streams so small that it seems extraordinary that so bulky 

 a creature can dwell in them without being always in evi- 

 dence; but in such streams it always finds some pool or quiet 

 reach with a fringe of reeds or bush that offers it a chance 

 to hide during the daytime. Where much molested it be- 

 comes excessively shy, and during daylight often lies for 

 hours with only its nostrils above water, in the shelter of 

 some tuft of water-grass or the like ; and under such circum- 

 stances it is astonishingly hard to make out. But on the 

 Nile, among the channels and shallows of the vast beds 

 of papyrus, we frequently saw small herds or family par- 

 ties of the obese, unwieldly creatures sunning themselves 

 even at noon, half out of water, or out on the shore, with 

 their heads resting on the mud or on one another's bodies. 

 Biting flies hover over them, and instead of the ticks which 

 infest the elephant and rhino the hippos are hosts of small 

 leeches which are often found in swarms fixed to the more 

 tender parts. Not only have we seen herons and plover 

 walking about and over them, but also birds that looked 

 like tick-birds. 



