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try to steal the young fawns. The tactics of a doe in defending 

 her family from a dog are sympathetically described by Hofer, 

 but no doubt an antelope mother would put up a more 

 desperate fight against coyotes alone than against a dog in 

 the presence of its human master. 



The ecologic significance of a birth season four months 

 earlier at the southern end of the Colorado Desert than along 

 various parts of the Mexican border is still to be divined. 

 Doubtless, however, it has a close relation to the grow- 

 ing season of the annual plants, and is secondarily con- 

 nected with the extraordinarily hot, dry summer climate 

 of the northern Lower Calif ornian deserts. The difference in 

 the time of this most important of all functions must, of course, 

 affect the antelope's whole fife history. It must relegate the 

 rutting period to early summer, instead of September or 

 October as in the western United States; furthermore, it 

 might be expected to have an effect upon the season of the 

 molt and the dropping of the horns. 



Little specific information appears to have been published 

 regarding the food plants of the pronghorn antelope. Caton 

 (1877) writes that the wild herds live on ''buffalo grass," and 

 that captive specimens in his deer-park grazed freely upon 

 standing blue grass, and also ate hay. Hornaday (1908) 

 found the antelopes in the Pinacate section of Sonora cropping 

 a species of desert plantain (Plantago) that grew in the lava 

 fields. The Lower Californian animals undoubtedly subsist 

 throughout most of the year upon various kinds of sun-cured 

 vegetation, but during the brief spring season of verdure they 

 seem to prefer tender leafage. Although desert bunch-grass, 

 called by the Mexicans ''guayeta," was common in scattered 

 patches on the lower slopes of Pattie Basin, I looked in vain 

 for evidence that the antelopes had fed upon it. Captain 

 Funcke maintained that they ate no grass at any season of the 

 year. The foliage of the trailing, lavender-flowered ''four 

 o'clock," Ahronia villosa, which grew in sandy parts of the 

 Creosote Association, was a favorite forage. Another plant 

 that they crushed and mouthed, apparently for the moisture 

 it contained, was the desert broom-rape, Orohanche multi flora. 



