12 ANIMAL LIFE OF CARLSBAD CAVERN 



rats, pocket mice, lechuguilla pocket gopher, Rio 

 Grande spotted skunk, Mearns white-backed skunk, 

 Texas skunk, guano bat, little canyon bat, and house 

 bat. 



Some of the conspicuous Lower Austral zone birds 

 are the road-runner, cactus woodpecker, Texas night- 

 hawk, Cassin kingbird, white-necked raven, Scott 

 oriole, hooded oriole, desert sparrow, painted bunting, 

 western mockingbird, cactus wren, and plumbeous 

 gnatcatcher. 



Among the Lower Austral reptiles are the Texas 

 diamond-back rattlesnake, leopard lizard, Texas 

 spotted-tailed lizard, Clark scaly lizard, whip-tailed 

 lizard, and Texas horned lizard (horntoad). 



Neither plants nor animals, however, are evenly 

 distributed in their zones, but each species is pushing 

 and striving for its place in the sun, and its room in the 

 soil, for its right to live and reproduce its kind. No- 

 where is the struggle for existence more fierce and 

 relentless, or adaptation and specialization carried to 

 a higher degree, than in the desert. The slightest tilt 

 of level that makes available a little more sunshine or 

 a little more moisture, a dike that catches and holds a 

 little more soil and plant food, a combination of ele- 

 ments of earth and soil in any way favorable to plant 

 life, are quickly taken advantage of, not only by the 

 strong and vigorous, but by the small and weak, in a 

 test of power to take, and strength to hold, possession. 

 On the other hand, the unfavorable slope that with 

 baked surface excludes moisture, or with excess of 

 unfavorable mineral content bars certain forms of 



