NATURAL HISTORY OF SOUTH AFRICA 



would be expert in the water owing to its awkward- 

 looking, barrel-like body and stumpy legs devoid 

 of webbed or even large feet. Nevertheless it is 

 an expert and rapid swimmer, and is able to make 

 headway against, the strongest currents. A most 

 remarkable thing about the Hippo is that it is 

 able to sink itself in deep water and walk along the 

 bottom, rising to breathe about every five or six 

 minutes. In this way it eludes its enemies, and 

 travels long distances up and down the rivers in 

 safety. This power of walking on the river bottom 

 is due to its specific gravity being almost equal to 

 that of water. 



During the rainy season, when rivers are running 

 freely, the Hippos sometimes travel up them to 

 near their sources. Selous records having observed 

 one in Rhodesia at an elevation of about 4000 feet 

 above sea-level. On the approach of the dry season, 

 the Hippos again retire to the lower reaches and 

 mouths of the rivers, or to the permanent water 

 holes or Zeekoegats. When these gats are near to each 

 other, the Hippos sometimes make a communicating 

 ditch or trench in the dry river-bed, along which 

 they travel from one hole to another. 



A Hippo can, if hard pressed, remain under water 

 about four and a quarter minutes. 



Although so short-legged and ungainly, the Hippo 

 can travel on flat ground as fast as an active man 

 can run. 



At the mating season the bulls fight a series of 

 162 



