Chap. III.] MORAL SENSE 71 



aud the other wrong ; but to these terms I shall have to 

 recur. 



Sociability. — Anunals of mauy kinds are social ; we 

 find even distinct species living together, as with some 

 American monkeys, and with the united flocks of rooks, 

 jackdaws, and starlings. Man shows the same feeling in 

 his strong love for the dog, which the dog returns with 

 interest. Every one must have noticed how miserable 

 horses, dogs, sheep, etc., are when separated from their 

 companions ; and what affection at least the two former 

 kinds show on their reunion. It is curious to speculate- 

 on the feelings of a dog, who will rest peacefully for hours 

 in a room with his master or any of the family, without 

 the least notice being taken of him ; but, if left for a short 

 time by himself, barks or howls dismally. We will con- 

 fine our attention to the higher social animals, excluding 

 insects, although these aid each other in many important 

 ways. The most common service which the higher ani- 

 mals perform for each other, is the warning each other of 

 danger by means of the united senses of all. Every 

 sportsman knows, as Dr. Jaeger remarks,^ how difficult it 

 is to approach animals in a herd or troop. Wild horses 

 and cattle do not, I believe, make any danger-signal ; but 

 the attitude of any one who first discovers an enemy, 

 warns the others. Rabbits stamp loudly on the ground 

 with their hind-feet as a signal : sheep and chamois do the 

 same, but with their fore-feet, uttering likewise a whistle. 

 Many birds and some mammals post sentinels, which in 

 the case of seals are said ' generally to be the females. 

 The leader of a troop of monkeys acts as the sentinel, and 

 utters cries expressive both of danger and of safety.* So- 



* ' Die Darwin'sche Theorie,' s. 101. 

 ' Mr. R. Browne in 'Proc. Zoolog. Soc' 18G8, p. 409. 

 8 Brehm, ' Thierleben,' B. i. 1864, s. 52, 79. For the case of llie iiion- 

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



