AGGREGATIONS OF ANIMALS 101 



swarms from twenty or more well populated bee- 

 hives which have settled near together. 



On the land the story is similar; dancing aggre- 

 gations of midges which appear like animated 

 particles are well known to all country folk. 

 Flocks of birds, herds of deer, hordes of lemmings 

 and even concentrations of snakes are all well 

 known. 



The colonies of social insects have received par- 

 ticular attention. Near Chicago there is a mound- 

 building ant which forms mounds from ten 

 inches high and a foot in diameter to those three 

 feet high and over seven feet in greatest length. 

 The tunnels of such nests extend farther below the 

 surface than the mounds pile up above it. These 

 mounds are not scattered indiscriminately about 

 but are themselves concentrated in two main 

 localities. The largest of these contains 400 

 nests in a patch of oak woodland that covers 

 only one-ninth of a square mile. 1200 colonies 

 of another species of ant have been counted on a 

 single acre of Manitoba prairie. 



Many of these colonies contain great numbers 

 of individuals; the eastern relative of the mound- 

 building ant of the Chicago area has been calcu- 

 lated to average 10,000 individuals in a colony; 

 its European relatives have from 30,000 to 

 100,000 ants and tropical colonies of termites have 



