ORGANISATIONS 389 



1. At night, or during the sleep of the flock or herd, to 

 guard against surprise. 



2. During feeding, rest on a march, or pastimes. 



3. In war, on the march or halt, in camp or bivouac 

 here also to prevent surprise. 



It is their duty to sound or give the alarm on the 

 approach of an enemy, or the threatening of any danger. 

 If a sentinel fail in this duty, for instance, by being cap- 

 tured or destroyed before he can perform it, the capture of a 

 whole herd may become easy. Thus the German Arctic 

 Expedition inform us that Greenland seals ' set a watch 

 before they go to sleep, which watch being killed, the whole 

 herd may often be taken.' In such a case, however, it 

 may be that the watchman is also a leader, in whose ab- 

 sence the same kind of helplessness from mental confusion 

 and panic ensues as in the case of bees and some other 

 animals. 



In connection with the appointment of sentinels the 

 following points have to be noticed : 



1. That, as in the case of leaders, the animals selected 

 are almost invariably males. 



2. That every advantage is taken of elevated ground 

 commanding a view on ah 1 sides. 



3. That the animal appointed is implicitly trusted by the 

 rest ; it has a specific duty to discharge, and it performs it 

 conscientiously. 



4. There must therefore be an appreciation of the dif- 

 ferent kinds of danger, as well as an idea of duty in relation 

 to that danger. 



Certain African antelopes place sentries generally bulls 

 while they are grazing, and these sentries take up their posts 

 on the summits of ant-hills, which form the only heights in 

 certain parts of the plains of the Nile. Their occupancy of 

 such watch-towers is, however, unfortunate for themselves 

 in presence of the sportsman, to whom they thus readily 

 become a marked prey (Baker). 



Californian quails as naturalised in New Zealand 

 'always keep a sentry perched on the stump of a neigh- 

 bouring tree, to give them timely warning of the approach 



