THE REDISCOVERED COUNTRY 357 



number of species — would raise their heads, stare for a 

 moment, and join the stampede. None but the first little 

 group had seen me, but all had caught the warning of danger 

 from the flash of stripe and colour, and all were heeding it. 

 On one occasion, six minutes by the watch after the first 

 beasts had departed, game was still plodding by across our 

 front. They were plodding very slowly and mechani- 

 cally and in a bored fashion, because by now the warning 

 had been much diluted, but they were doing their duty. 

 Now of all these beasts nine tenths were more or less un- 

 noticeable as long as they stood still. Their coloration, or 

 the light or the cover, or all three tended to obliterate most 

 of them sufficiently to cause them to be overlooked by a 

 cursory glance. But the moment any of them moved, 

 they became instantly and plainly visible. In other words, 

 the same pattern that fulfilled one function one moment in 

 certain circumstances fulfilled another function the next 

 moment in changed circumstances. To go back to our 

 zebra, because he is easy to discuss, no creature was harder 

 to make out in thin cover as long as he held still; no animal 

 was easier to see the instant he moved. As long as he held 

 still he was presumably in no danger of which he was aware, 

 and his pattern helped him to remain unobserved; the in- 

 stant he became aware of danger and ran, that instant by 

 his very conspicuousness he served as an easily visible warn- 

 ing to all other beasts that something was wrong. 



It is useless to discuss the point played by coloration in 

 recognition and sex attraction. The uniform of a par- 

 ticular species is as definite as the imiform of a regiment, 

 and perhaps fulfills much the same function. Of course 



