172r THE WOELD OF LIFE 



lecture on the Colours of Animals given at many places in 

 the United States and Canada in 1886-87, and in England in 

 1888. No doubt some of the facts had been noted by other 

 writers, but I thinlv I was the first to claim for it a high place 

 among the factors concerned in animal evolution. The clear- 

 est and most picturesque illustration of the subject 1 have seen 

 is in a very short article by Mr. E. Seton Thompson in the 

 American periodical " The Auk " for October 1897, from 

 which I will quote the most important passage : 



" The common jack-rabbit ^ when squatting under a sage-bush 

 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 

 diflScult 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 jach-rabhit. 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 that 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-rab- 

 bit, and saves it much pains to escape from real or imaginary 

 dangers. As soon as it squats again all the directive marks disap- 

 pear, and the protective gray alone is seen. In the bird-world the 

 same general rule applies. When sitting, birds are protectively 

 coloured; when flying, directivelyf i 



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 scat- 



1 This appears to be the common grey hare {Lepiis a^nericanus) . 



