grass prairie is the so-called bread basket of our 

 modern civilization. 



SUMMARY 



Grasslands occur on all continents and are 

 marked by low amounts of precipitation and high 

 rates of evaporation. Climax grasses are mostly per- 

 ennial and are characteristically tall, medium, or 

 short in stature. Since their leaves grow at the base, 

 they tolerate grazing by animals, and it is in this 

 biome that ungulate mammals and rodents attain 

 large population densities. 



The large herbivorous ungulates commonly go in 

 herds, are fleet on foot, and have long-range vision. 

 Some species of rodents form large colonies and dig 

 extensive underground burrows. Locomotion by 



hopping occurs in several mammals and some insects. 

 Protective coloration is well developed in many kinds 

 of animals. L'pland birds are strong fliers and com- 

 monly have flight songs. Scattered ponds surrounded 

 by marsh have concentrations of many nesting spe- 

 cies of birds and are the source of drinking water for 

 the large mammals. Migration is well developed 

 among birds and hibernation among small mammals, 

 reptiles, amphibians, and invertebrates so that there 

 is a nearly complete absence of animals above ground 

 during the winter months. Only one biociation is 

 recognized in North America and in each of the other 

 continents. 



The more humid grassland areas make very fer- 

 tile and productive agricultural land for man while 

 the drier portions are best used for grazing of do- 

 mestic animals. 



Grassland biome 331 



