58 ANIMAL LIFE AND SOCIAL GROWTH 



At the present time Drummond's vole, often 

 called a meadow mouse, is the most abundant 

 and the most influential animal, man and his 

 beasts aside. It has been found to be impractical 

 to attempt an estimate of the numbers of these 

 voles present per acre but every square foot of 

 prairie is crossed by their runways. They feed 

 entirely on plants, and hence are true "key- 

 industry" animals in that they convert the grasses 

 into meat which is then a source of food for hawks, 

 coyotes, weasels and the great horned owl. Where 

 in the boyhood of my father the mighty and pic- 

 turesque bison roamed in countless numbers, 

 so many that men could smell them at a dis- 

 tance, today the retiring, apparently insignificant 

 meadow mouse is the most important wild 

 animal left! 



The crow, the introduced partridges, the leop- 

 ard frogs, meadowlarks, insects in general and 

 particularly ants and invertebrates as a group may 

 be considered to be important prairie animals. Of 

 these, the invertebrates reach a total population 

 of about 6,000,000 per acre upon the prairie 

 in March at a time when the larger animals are 

 still hibernating. As these emerge and become 

 active, the numbers of insects decrease until in 

 June there are only about a million per acre; 

 then with more favorable conditions their numbers 



