386 AFRICAN GAME ANIMALS 



standing motionless and alert on a neighboring ant-hill. 

 Such animals are often spoken of as sentinels, as delib- 

 erately performing, and set to perform, sentinel duty for 

 the herd. Much study of the herds left us in doubt as to 

 whether this was or was not the case; as to whether there 

 was more in the habit than the individual suspiciousness 

 and wariness of an animal concerned only with his safety 

 and not thinking about his companions at all. Often we 

 saw herds where there were one or more individuals on the 

 lookout, which therefore in effect acted as sentinels; but 

 more often the herds were grazing, resting, or lying down 

 without any sentinels. Moreover, if the seeming sentinel 

 lay down or began grazing there was normally no attention 

 paid by the rest of the herd and no attempt made to sup- 

 ply its place by another sentinel. Yet once, when the 

 possible sentinel descended from his post on an ant-hill, we 

 certainly saw another take his place; but this one may 

 merely have been rendered uneasy by his companion's 

 movements and have risen to look round on his own ac- 

 count; for when, after half an hour's motionless watching, 

 the beast became satisfied, descended and began to graze, 

 no other animal took his place or paid heed to what had 

 happened. When startled or puzzled the lookout animal 

 might give the kind of sneeze spoken of above. With both 

 hartebeest and wildebeest we have seen single individuals 

 watching, on the grazing-grounds and at the watering- 

 places, under circumstances that made it seem as if they 

 were deliberately acting as sentinels for the herd; but we 

 never were sure that this was the case or that the an- 

 imal was behaving otherwise than it would have behaved 

 if entirely alone. Indeed, we are inclined to think that the 



