lo8 THE SOCIAL LIFE OF ANIMALS 



of South Africa, came to spend some weeks with us. 

 He told us that the Knysna Forest, a protected wood- 

 land in South Africa, has an area of 225 square miles, 

 fifteen miles on a side, and that this forest is the 

 home of a herd of eleven elephants, which can also 

 range outside the forest limits. On the other hand, 

 the Addo Forest, of twenty-five to thirty square miles, 

 supports a herd of twenty-four elephants. (98) Dr. 

 Phillips thinks that the smaller herd is not maintain- 

 ing itself, and that the larger one, under apparently 

 less favorable conditions as regards available area of 

 range, is at approximately the lower limit for keep- 

 ing up its own numbers. He estimates that an ele- 

 phant herd of about twenty-five individuals could 

 maintain itself in an unrestricted range providing 

 civilized man were absent. 



He gave us a second example, of a herd of some 

 three hundred springbok on a protected reserve of 

 six thousand acres in the Transvaal, which was un- 

 able to maintain its numbers and became reduced 

 to eighty or ninety, on its way toward total ex- 

 tinction. 



It is well known that in the life of equatorial 

 Africa the tsetse fly plays an important part. It carries 

 the trypanosomes which cause the deadly disease, 

 "sleeping sickness," of man and his domestic animals, 

 and which affect native game as well. The British 



