v SOCIAL LIFE OF ANIMALS 77 



degree of integration the more indispensable does each part be- 

 come, and the more perfectly do the activities of the parts blend 

 in the harmonious life of the whole. At a higher level, this is 

 sometimes illustrated in the life of industrial organisations, com- 

 munities, nations, and empires. 



3. Gregarious Life and Combined Action. Most mam- 

 mals are in some degree gregarious. The solitary kinds 

 are in a distinct minority. The isolated are exposed 

 to attack, the associated are saved by the wisdom of 



> 



their wisest members and by that strength which union 

 gives. Many hoofed animals, such as deer, antelopes, 

 goats, and elephants, live in herds, which are not mere 

 crowds, but organised bands, with definite conventions 

 and with a power of combined resistance which often 

 enables them to withstand the attacks of carnivores. 

 Marmots and prairie-dogs, whose ' cities ' may cover 

 vast areas, live peaceful and prosperous lives. Monkeys 

 furnish many illustrations of successful gregarious life. 

 As individuals most of them are comparatively defence- 

 less, and usually avoid coming to close quarters with 

 their adversaries ; yet in a body they are formidable, and 



J mJ m, 



often help one another out of scrapes. Brehm tells how 

 he encountered a troop of baboons which defied his dogs 

 and retreated in good order up the heights. A young 

 one about six months old being left behind called loudly 

 for aid. " One of the largest males, a true hero, came 

 down again from the mountain, slowly went to the 

 young one, coaxed him, and triumphantly led him away 

 -the dogs being too much astonished to make an attack." 

 Many birds, such as rooks and swallows, nest together, 

 and the sociality is often advantageous. Kropotkin 

 cites from Dr. Coues an observation in regard to some 

 little cliff-swallows which nested in a colony quite near 

 the home of a prairie-falcon. " The little peaceful birds 

 had no fear of their rapacious neighbour ; they did not 

 let it even approach to their colony. They immediately 

 surrounded it and chased it, so that it had to make off 

 at once." Of the cranes, Kropotkin notes that they are 

 extremely " sociable and live in friendly relations, not 

 only with their congeners, but also with most aquatic 



