The Yellowstone Rivo- rises in the Rockies, then descends onto the prairies, loses impetus, and 

 begins to meander and to cut a deep gutter. 



stemmed shrubs, followed in turn by hardy trees such as the 

 beautiful, useful, but in many respects almost indestructible 

 Mesquite, which has now moved up from southern Texas as far 

 as Kansas and is being held back only by considerable effort 

 from that area of western Texas called the Llano Estacado. The 

 Prairie Dog was master and part maker of the prairie, but he 

 was not alone. 



There was, and still is, another burrower and an even more 

 profound one. This is the Pocket Gopher, a really appalling- 

 looking creature, with tiny eyes, vast front teeth stuck out at the 

 end of a fully furred but bony snout, powerful front legs with 

 huge claws for digging, little trundling hind legs, and a loose- 

 skinned tail that can be used as a feeler when the animal goes 

 backward, which it can do as readily and as fast as it can go 

 forward. Unlike the Prairie Dog, the Pocket Gopher spends 

 almost all its time down below, endlessly burrowing and throw- 

 ing up small mounds of excess earth. The Pocket Gopher (not 

 to be confused with the plain gophers or ground squirrels) does 

 not live where the Prairie Dog is found, or vice versa. On the 

 pure grasslands there is nothing below the surface but grass 

 roots, and these are not acceptable to the Pocket Gopher. They 

 need bulbs and roots, so they go to work under areas where 

 herbs, bushes, and trees grow. There they do a very effective job 

 of "mowing" all those types of vegetation from underneath, 

 thus eliminating them. 



The part played by these animals under natural conditions 

 was to hold back, if not actually to push back, the scrub and 

 chaparral on the south and the parkland woods on the north of 

 the Prairie Belt. They did this by cutting off the individual plants 

 of these types at the base of their stems just as soon as they 

 gained a footing, and then toting these treasures down into the 

 subsoil and stowing them away in caches. The efficacy of their 

 efforts may be dramatically demonstrated when a parcel of these 

 animals moves into a young and thriving orchard. They move 

 down the lines of young trees at a surprising rate, cutting them 

 off neatly just below the surface so that, within hours, they wilt, 

 die, and topple. I have seen them completely destroy a thriving 

 citrus plantation in the tropics in one night. The Pocket Gophers 

 had — and still have — few enemies except for certain fungoidal 

 diseases that periodically decimated their ranks, for they are 

 agile at digging, and drill their tunnels deep into the subsoil. 



NATURE'S BALANCE 



The Prairie Dog, on the other hand, once had many enemies, 

 which is to say — if we would be more biologically precise — it 

 formed the staple item in a large food cycle, for animals do not, 

 of course, have "enemies." Prairie Dogs shared their dominions 

 with a large number of other creatures, notably burrowing owls, 



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