American Prong-Horn 



haps come in view, and once more stand and gaze at the in- 

 truder." 



The wonderful watchfulness of the antelope is due naturally 

 to its continual exposure in the open country in which it lives 

 and the necessity of being ever prepared to get a clear start of 

 the wolves or such other enemies as may harass it, against 

 which flight is its only safeguard. 



Like many other animals that habitually associate in flocks, 

 the antelope has in its two white rump patches conspicuous 

 "recognition marks," as they have been termed, by which, ac- 

 cording to Wallace's theory, individuals can at a glance recog- 

 nize their own kind, even though at a considerable distance. The 

 rump patches of the antelope, however, are different from those 

 of other ruminants and are of much more importance to the 

 animal. Ernest Seton-Thompson, writing of this matter in The 

 Century Magazine, says: "Some years ago, while riding across 

 the upland prairie of the Yellowstone, I noticed certain white 

 specks in the far distance. They showed and disappeared seve- 

 ral times and then began moving southward. Then, in another 

 direction, I discovered other white specks which also seemed to 

 flash and disappear. A glass showed them to be antelope, but 

 it did not wholly explain the flashing or the moving which ul- 

 timately united the two bands. I made note of the fact, but 

 found no explanation until the opportunity came to study the 

 antelope in the Washington Zoo." He goes on to explain how 

 the approach of a dog to the enclosure of the captive animals 

 caused them to elevate the hair all over their rump patches. 

 "The wild antelope habit is to raise the head while grazing to 

 keep a sharp lookout for danger, and these captives kept up 

 the practice of the race. The first that did so saw the dog. It 

 uttered no sound, but gazed at the wolfish-looking intruder and 

 all the long white hairs of the rump patch were raised with a 

 jerk that made the patch flash in the sun like a tin pan. Every- 

 one of the grazing antelopes saw the flash, repeated it instantly 

 and raised his head to gaze in the direction in which the first 

 was gazing. At the same time I noticed on the wind a pecu- 

 liar musky smell a smell that certainly came from the antelope." 

 Subsequent investigation showed the presence of a musk gland 

 in the centre of the rump patch and a mass of muscle connected 

 with it and with the bases of the white hairs. This completed 



56 



