160 THE WORLD OF LIFE CHAP. 



is simply a sage-gray lump without distinctive colour or form. Its 

 colour in particular is wholly protective, and it is usually accident 

 rather than sharpness of vision which betrays the creature as it 

 squats. But the moment it springs it is wholly changed. It is 

 difficult to realise that this is the same animal. It bounds away 

 with erect ears showing the black and white markings on their back 

 and underside. The black nape is exposed. The tail is carried 

 straight down, exposing its black upper part surrounded by a region 

 of snowy white ; its legs and belly show clear white, and everything 

 that sees it is clearly notified that this is a jack-rabbit. The coyote, 

 the fox, the wolf, the badger, etc., realise that it is useless to follow ; 

 the cotton-tail, the jumping rat, the fawn, the prairie dog, etc., that 

 it is needless to flee; the young jack-rabbit jthat this is its near 

 relative, and the next jack-rabbit that this may be its mate. And 

 thus, though incidentally useful to other species at times, the sum 

 total of all this clear labelling is vastly serviceable to the jack-rabbit, 

 and saves it much pains to escape from real or imaginary dangers. 

 As soon as it squats again all the directive marks disappear, and the 

 protective gray alone is seen. In the bird-world the same general 

 rule applies. When sitting, birds are protectively coloured ; when 

 flying^ directivcly? 



The African antelopes offer very striking examples of 

 " recognition "- marks, especially those that inhabit Central 

 and South Africa, where such indications are most needed. 

 The land is generally open, often quite bare, but usually 

 with scattered trees and bushes ; and as these animals roam 

 over a great extent of country in search of food or water, 

 and are also liable to the attacks of many dangerous beasts 

 of prey, their safety depends largely on their keeping 

 together in small or large herds. There are nearly a 

 hundred different kinds of antelopes known to inhabit 

 Africa, the larger part of them being found in Central and 

 South Africa. Almost all of these have very distinctive 

 markings on a general ground-colour harmonising with the 

 tint of the soil or rock. These markings are usually con- 

 fined to white patches on the head and face, and on the 

 hinder parts, so as to be visible in the two directions that 

 are most serviceable. 1 I have also come to the conclusion 

 that the horns of these animals, though primarily developed 



1 The beautiful gazelle figured in my Darwinism (p. 219) shows both these 

 kinds of markings very strongly ; while an examination of the numerous figures 

 of antelopes in Wood's Natural History (or in any of the more recent illustrated 

 works) affords numerous examples of them. 



