PROTECTIVE COLORATION 511 



beneficially affected by its protective coloration. The two animals 

 cannot both be protectively coloured ; they cannot each owe to its 

 coloration an advantage in escaping from its foes. It is absolutely 

 impossible, if one of them is so coloured as to enable it to escape 

 the observation of its foes, that the other can be. As a matter of 

 fact, neither is, and neither makes any attempt to elude observa- 

 tion by its foes, but trusts entirely to vigilance in discerning them 

 and Heetness in escaping from them ; although the wild ass, unlike 

 the zebra, really is so coloured that because thereof it may occa' 

 sionally escape observation from dull-sighted foes. 



Mr. Thayer's argument is based throughout on a complete 

 failure to understand the conditions of zebra life. He makes an 

 elaborate statement to show that the brilliant cross-bands of the 

 zebra have great obliterative effect, insisting that, owing to the 

 obliterative coloration, zebras continually escape observation in 

 the country in which they live. He continues : " Furthermore, all 

 beasts must have water, and so the zebras of the dry plains must 

 needs make frequent visits to the nearest living sloughs cind rivers. 

 There, by the water's edge, tall reeds and grasses almost always 

 fiouri.sh, and there, where all beasts meet to drink, is the great 

 place of danger for the ruminants, and all on whom the lion preys. 

 In the open land they can often detect their enemy afar off', and 

 depend on their fleetness for escape ; but when they are down in 

 the river-bed, among the reeds, he may approach unseen and leap 

 among them without warning. It is probably at these drinking- 

 places that the zebra's pattern is most beneficently potent. From 

 far or near the watching eye of the hunter (bestial or human) is 

 likely to see nothing, or nothing but reed-stripes, where it might 

 otherwise detect the contour of a zebra." In a footnote he adds 

 that, however largely lions and other rapacious mammals hunt by 

 scent, it is only sight that serves them when they are down wind 

 of their quarry ; and that sight alone must guide their ultimate 

 killing dash and spring. 



Now, this theory of Mr. Thayer's about the benefit of the zebra's 

 coloration at drinking-places, as a shield against foes, lacks even 

 the slightest foundation in fact; for it is self-evident that animals, 

 when they come down to drink, necessarily move. The moment 

 that any animal the size of a zebra moves, it at once becomes 

 visible to the eye of its human or bestial foes, unless it skulks in 

 the most cautious manner. The zebra never skulks, and, like most 

 of the plains game, it never, at least when adult, seeks ho escape 

 observation — indeed, in the case of the zebra (unlike what is true 

 of the antelope) I am not sure that even the young seek to escape 

 observation. I have many times watched zebras and antelopes — 

 wildebeest, hartebeest, gazelle, waterbuck, kob — coming down to 

 water ; their conduct was substantially similar. The zebras, for 



