238 Life-histories of Northern Animals 



stone and Missouri Rivers, destroying apparently three-fourths 

 to nine-tenths of them. The greatest fatahty seems to have oc- 

 curred in July, judging from the size of the fawns found dead, 

 and hence not long after we crossed this portion of the country. 

 From the head of Heart River to the Missouri we found their 

 carcasses, on our return, thickly scattered along our hne of 

 march, including those of both sexes and all ages, fawns being 

 often found lying within a few yards of their dams. On our way 

 out Antelope were almost constantly in sight, but on our return 

 they were only rarely met with, ten dead ones being seen to each 

 living one. The epidemic seems not to have extended beyond 

 the Yellowstone, where they seemed more numerous on our re- 

 turn than on our way out, and where no dead ones were observed. 



"The previous year they are reported to have ranged over 

 this section of the country, in autumn, in very large numbers, 

 bands of two or three hundred being sometimes met with by 

 the Yellowstone Expedition of 1872, on its return eastward. 

 Four were captured by the men as the frightened animals 

 attempted to run through the train. 



'^Epidemics similar to that affecting the Pronghorns are well 

 known to occasionally affect Deer, Rabbits, and Field-mice." 



LIFE During the winter the Antelope live in mixed bands of all 



ages and sizes. Nowadays these bands are commonly 10 to 

 50 in number, but in earlier days, I am told, several hundred, 

 even thousands, would run together. 



Early in the spring the usual inevitable disposition to 

 scatter manifests itself. The separation of the sexes seems to 

 be due to an instinctive dislike of each other, as the time ap- 

 proaches for the young to be born. It becomes yet stronger as 

 the hour draws near. At that time each female strives to be 

 utterly alone. She avoids even the few remaining companions 

 of her own sex, and retires to some secluded spot. 



YOUNG Parturition takes place in late May or early June, on the 



Yellowstone, but may be earlier farther south. The fawns 

 or kids are commonly 2 in number. Their mother hides them 

 close together for several days, visiting them at frequent inter- 



