98 THE DESCENT OF MAN. 



tinel, and utters cries expressive both of clanger and of safety." 

 Social animals perform many little services for each other: horses 

 nibble, and cows lick each other, on any spot which itches: monk- 

 eys search each other for external parasites; and Brehm states 

 that after a troop of the Cercopithecus griseo-viridis has rushed 

 through a thorny brake, each monkey stretches itself on a branch, 

 and another monkey sitting by, "conscientiously" examines its 

 fur, and extracts every thorn or burr. 



Animals also render more important services to one another: 

 thus wolves and some other beasts of prey hunt in packs, and 

 aid one another in attacking their victims. Pelicans fish in con- 

 cert. The Hama'dryas baboons turn over stones to find insects, 

 &o. ; and when they come to a large one, as many as can stand 

 round, turn it over together and share the booty. Social animals 

 mutually defend each other. Bull bisons in N. America, when 

 there is danger, drive the cows and calves into the middle of the 

 herd, whilst they defend the outside. I shall also In a future chap- 

 ter give an account of two young wild bulls at Chillingham at- 

 tacking an old one in concert, and of two stallions together trying 

 to drive av/'ay a third stallion from a troop of mares. In Abyssinia, 

 Brehm encountered a great troop of baboons, who were crossing 

 a valley: some had already ascended the opposite mountain, and 

 some were still in the valley: tlie latter were attacked by the 

 dogs, but the old males immediately hurried down from the rocks, 

 and with mouths widely opened roared so fearfully, that the dogs 

 quickly drew back. They were again encouraged to the attack; 

 but by this time all the baboons had reascended the heights, ex- 

 cepting a young one, about six months old, who, loudly calling 

 for aid, climbed on a block of rock, and was surrounded. Now 

 one of the largest males, a true hero, came down again from the 

 mountain, slowly went to the young one, coaxed him, and trium- 

 phantly led him away — the dogs being too much astonished to 

 make an attack. I cannot resist giving another scene which was 

 witnessed by this same naturalist; an eagle seized a young Cerco- 

 pithecus, which, by clinging to a branch, was not at once carried 

 off; it cried loudly for assistance, upon which the other members 

 of the troop, with much uproar, rushed to the rescue, surrounded 

 the eagle, and pulled out so many feathers, that he no longer 

 thought of his prey, but only how to escape. This eagle, as Brehm 



» Brehm, 'Thierleben,' B. i. 18G4, s. 52, 73. For the case of the mon- 

 keys extracting thorns from each other, see s. 54. With respect to the 

 Hamadryas turning over stones, the fact is given (s. 76) on the evi- 

 dence of Alvarez, whose observations Brehm thinks quite trustworthy. 

 For the cases of the old male baboons attacking the dogs, see s. 79; 

 and with respect to the eagle, s. 56. 



