APPENDIX E 503 



cover, in which case they always seemed more nervous, more on the 

 alert, and quicker in their movements. They came down in herds, and 

 they would usually move forward by fits and starts; that is, travel a 

 few hundred yards, and then stop and stand motionless for some time, 

 looking around. They were always very conspicuous, and it was quite 

 impossible for any watcher to fail to make them out. As they came nearer 

 to the water, they seemed to grow more cautious. They would move 

 forward some distance, halt, perhaps wheel and dash off for a hundred 

 yards, and then after a little while return. As they got near the water 

 they would again wait, and then march boldly down to drink except 

 in one case where, after numerous false starts, they finally seemed to 

 suspect that there was something in the neighborhood, and went off for 

 good without drinking. Never in any case did I see a zebra come down 

 to drink under conditions which would have rendered it possible for the 

 most dull-sighted beast to avoid seeing it. Of course I usually watched 

 the pools and rivers when there was daylight; but after nightfall the 

 zebra's stripes would be entirely invisible, so that their only effect at the 

 drinking-place must be in the daytime; and in the daytime there was 

 absolutely no effect, and the zebras that I saw could by no possibility 

 have escaped observation from a lion, for they made no effort whatever 

 thus to escape observation, but moved about continually, and, after drink- 

 ing, retired to the open ground. 



The zebra's coloration is certainly never of use to him in helping him 

 escape observation at a drinking-place. But neither is it of use to him 

 in escaping observation anywhere else. As I have said before, there are 

 of course circumstances under which any pattern or coloration will har- 

 monize with the environment. Once I came upon zebras standing in 

 partially burned grass, some of the yellow stalks still erect, and here the 

 zebras were undoubtedly less conspicuous than the red-coated hartebeests 

 with which they were associated; but as against the one or two occasions 

 where I have seen the zebra's coat make it less conspicuous than most 

 other animals, there have been scores where it has been more conspicu- 

 ous. I think it would be a safe estimate to say that for one occasion on 

 which the coloration of the zebra serves it for purposes of concealment 

 from any enemy, there are scores, or more likely hundreds, of occasions 

 when it reveals it to an enemy; while in the great majority of instances 

 it has no effect one way or the other. The different effects of light and 

 shade make different patterns of coloration more or less visible on different 



