ANIMAL LIFE OF THE COUNTRY. 37 



species dwindles and probably finally becomes extinct. It is prejudicial to any 

 animal to have a monopoly of one kind of vegetable food, as it then has no stimulus 

 to improvement. It grows stale and behindhand in the race for existence, and is 

 then at the mercy of any new species which may crop up with more energy and 

 vitality to throw into the struggle for existence. 



Where any food is abundant, such as is the grass of the plains, then the struggle 

 between species is almost nominal. Where, however, food is scarce and difficult to 

 obtain, the struggle is keenly contested and causes rapid changes in the habits and 

 forms of the contesting parties. Such a one has probably been continuing for eras 

 between Waller's and Clarke's gazelle. Each has been trying to fit itself more and 

 more for the scanty grazing off the mimosa and acacia tops. By the simple process 

 of the least fitted of each of these species going to the wall for want of sufficient 

 nourishment, their present forms have been produced. Each species has been 

 unconsciously trying to grow longer legs and necks so as to reach the grazing 

 untouched by its opponent. Apparently the Waller's has shown itself the more 

 fitted to survive, and this probably accounts for its wider distribution. The Clarke's 

 is gradually being ousted from the contest. Even now it is local and rare, which 

 conditions are eventually followed by its extinction, unless, indeed, it can take up 

 some new line before this entirely comes to pass. 



The giraffe is in the same line of contest, but is hardly a serious rival to these 

 gazelle, as it has grown out of their highest sphere of grazing and eats over 

 their heads. Perhaps this animal is the survivor from a bygone contest similar to 

 that now in progress between these gazelle. I can picture a prehistoric struggle 

 between the ancestors of the giraffe, not yet attained to its present size and form, 

 and other giraffe or okapi-like animals ; the gradual evolution to its present form 

 and the gradual dying out and extinction of the other competitors. Having arrived 

 at his present stature, he is now somewhat handicapped by finding himself saddled 

 with an enormous body which it must take all his energies to fill. 



Next, as to the effect on animals caused by their human neighbours. 



It is very easy to imagine that animals living near a race of hunters learn to be of 

 much more shy and retiring habits than those that live in an uninhabited country or 

 near non-hunting tribes. In the plains of East Africa, the only tribe inhabiting these 

 vast expanses is the Masai. They are a pastoral people, probably of northern origin. 

 To judge, however, from some of their cattle tracks, cut deep into rocky soil, they 

 have for centuries been grazing these plains Vv'ith their flocks and herds. Their food 

 consists only of the meat, blood, and milk of their stock. Other meats and other 

 foods they never touch in the ordinary course of events. Thus, they graze their 



