5. RHINOCEROS AND BUFFALO 



EFE in Africa is sensitively balanced. Among the grass 

 eaters there is cooperation for defense. A kongoni, 

 posted on an anthill, serves as a sentinel for herds of grazing 

 antelope and zebra. When a baboon or small monkey, 

 stationed high in a tree, sees a nearly submerged crocodile, 

 he will, through his own alarm, signal danger to animals 

 coming to drink. The beautiful buff-backed egrets and 

 white herons, suddenly rising from the high reeds and dense 

 papyrus, cause the near-by elephant and buffalo to be wary. 



As we trekked out to Lake Manyara one morning, we 

 saw a solitary rhinoceros in the high grass at the edge of the 

 sandy beach. Passing some fifty yards downwind of him, we 

 noticed small brown birds rising from his back. Immediately 

 sensing danger, he whirled and, catching the scent, started 

 in our direction; but when within 50 feet of us, he as 

 suddenly stopped, circled once or twice, then trotted off 

 into the bush. 



The insignificant ears of the rhinoceros testify to his lack 

 of enemies. The pigl'ike eyes show that sight is not a para- 

 mount factor in his survival. The rhinoceros depends upon 

 the small, red-beaked birds that perch upon his back to 

 serve as a warning to him. When these tickbirds fly from 

 him, the simple memory mechanism of the rhinoceros 

 associates danger. Thus the rhino bird and the rhinoceros 

 are in cooperation. 



Although the eyesight of the elephant and the hippopota- 

 mus is poor also, the elephant, the hippopotamus, and the 

 buffalo, having used their senses of sight and hearing to 

 detect danger, have evolved a greater intricacy of action 

 patterns than the rhinoceros. 



Wearing a heavy armored skin, the rhinoceros pushes 

 noisily along among the shrubs and bush, through thorns 

 and high grass, crushing everything before him. He sees 



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