GRAZING AND BROWSING 



121 



Small Grazers Resident Underground. This group includes notably 

 the prairie dogs, marmots, and conies in North America. Grasses and 

 forbs are also taken by certain species of kangaroo rats, ground squir- 

 rels, etc. There is no universal connection between subterranean habit 

 and grazing, but the animals of this group exhibit such a correlation 

 as an important feature of their community relations. Prairie dogs 



Total Protection 



PLOT 



Prairie Dog 



PLOT 



Cattle Grazed 



PLOT 



Fig. 30. — Fall clippings of blue grama (Boutcloua gracilh) in grazing exclosures 

 at Williams, Arizona. The pile labeled "cattle-grazed plot" is from the open 

 areas where both cattle and prairie dogs grazed. (After Taylor and Loftfield, 



1922.) 



crop herbs and also dig them out, their choice being somewhat the 

 same as that of the native ungulates and domestic animals. Marmots 

 (Marmota) usually choose forbs rather than grasses, owing to their 

 general relation to forest regions, while conies graze and store herbs 

 of all kinds. Another important characteristic of this group of grazers 

 is the occurrence of quiescence in many species during unfavorable 

 seasons. This takes them out of competition with the large grazers 



