On a p. IV. Moral Sense. 101 



of a troop of monkeys acts as the sentinel, and utters cries 

 expressive both of danger and of safety. 9 Social animals perform 

 many little services for each other : horses nibble, and cows lick 

 each other, on any spot which itches : monkeys search each 

 other for external parasites ; and Brehm states that after a troop 

 of the Cercopit'hecus grineo-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 lish in 

 concert. The Hamadryas baboons turn over stones to find 

 insects, &c. ; 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 chapter give an account of two young wild bulls at 

 Ohillingham attacking an old one in concert, and of two stallions 

 together trying to drive away 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 : the 

 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, excepting 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 triumphantly 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 Cercopithecus, 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, 



5 Brehm, ' Thierleben,' B. i. 1864, the evi lence of Alvarez, whose ob- 

 8. 52, '79. For ths case of the servaticas Brehm thinks quite trust- 

 monkeys extracting thorns from worth). For the cases of the old 

 each other, see s. 54. With respect male baboons attacking the dogs, 

 to the Hamadryas tinning over see s. 79 ; and with respect to th< 

 stones, the fact is given (s. 76) on eagle, s. 56 



