APPENDIX E 555 



such obliterative value would be at the precise moment when it happened 

 to be standing stern-on in such a position that the rump was above the 

 sky-line and all the rest of the body below it. Ten steps further back, 

 or ten steps further forward, would in each case make it visible instantly 

 to the dullest-sighted wolf or cougar that ever killed game, so that Mr. 

 Thayer's theory is of value only on the supposition that both the prong- 

 buck and its enemy happen to be so placed that the enemy never glances 

 in its direction save at just the one particular moment when, by a combi- 

 nation of circumstances which might not occur once in a million times, 

 the prongbuck happens to be helped by the obliterative quality of the 

 white rump mark. Now, in the first place, the chance of the benefit 

 happening to any individual prongbuck is so inconceivably small that it 

 can be neglected, and, in the next place, in reality the white rump mark 

 is exceedingly conspicuous under all ordinary circumstances, and for 

 once that it might help the animal to elude attention, must attract at- 

 tention to it at least a thousand times. At night, in the darkness, as 

 any one who has ever spent much time hunting them knows, the white 

 rump mark of the antelope is almost always the first thing about them 

 that is seen, and is very often the only thing that is ever seen; and at 

 night it does not fade into the sky, even if the animal is on the sky-line. 

 So far as beasts of prey are guided by their sight at night, the white rump 

 must always under all circumstances be a source of danger to the prong- 

 buck, and never of any use as an obliterative pattern. In the daytime, 

 so far from using this white rump as obliterative, the prongbuck almost 

 invariably erects the white hairs with a kind of chrysanthemum effect 

 when excited or surprised, and thereby doubles its conspicuousness. In 

 the daytime, if the animals are seen against the sky-line, the white rump 

 has hardly the slightest effect in making them less conspicuous; while if 

 they are not seen against the sky-line (and of course in a great majority 

 of cases they are not so seen), it is much the most conspicuous feature 

 about them, and attracts attention from a very long distance. But this 

 is not all. Any one acquainted with the habits of the prongbuck knows 

 that the adult prongbuck practically never seeks to protect itself from 

 its foes by concealment or by eluding their observation; its one desire is 

 itself to observe its foes, and it is quite indifferent as to whether or not it 

 is seen. It lives in open ground, wliere it is always very conspicuous; ex- 

 cepting during the noonday rest, when it prefers to lie down in a hollow, 

 almost always under conditions \*. hich render the white rump patch much 

 less conspicuous than at any other time. In other words, during the time 

 when it is comparatively off its guard and resting, it takes a position 

 where it does not stand against the sky-line as according to Mr.Thayer's 

 ingenious theory it should; and, again contrary to this same theory, it 

 usually lies down so that any foe would have to look down at it from 

 above. Whenever it does lie down, the white patch becomes less conspicu- 

 ous; it is rarely quiet for any length of time except when lying down. The 

 kids of the prongbuck, on the other hand, do seek to escape observation, 

 and they seek to do so by lying perfectly flat on the ground, with their 



