CHAPTER XXVII 

 ANIMAL DEFENCES— SPECIAL PRECAUTIONARY HABITS 



We have so far considered Precautionary Measures whereby 

 enemies are warded off, so far as they depend upon bodily charac- 

 teristics producing inconspicuousness or studied conspicuousness, 

 but certain Precautionary Habits of quite different kind are 

 equally important, and deserve a little attention. A great deal 

 of what might be said has of necessity been anticipated, for the 

 form and structure of animals can only be properly understood 

 when considered alono- with habits and surroundino^s. 



It has already been pointed out that animals are most ex= 

 posed to the attacks of enemies when they are on the move. 

 Excluding forms such as sponges, corals, sea-lilies, &c., we may 

 say that movements are more or less necessary for the purpose 

 of obtaining food. The risk thus incurred, however, may be 

 reduced by feeding at suitable times and in suitable places, while 

 safety between whiles may be gained by the existence of dwellings, 

 retreats, and temporary resting-places. 



FEEDING AT FAVOURABLE TIMES— NOCTURNAL 

 ANIMALS. (Fig. 489) 



This subject requires working out, so that only a few points 

 can be here presented for consideration. A very large number 

 of those animals most exposed to attack turn night into day, 

 and, in certain cases at any rate, the nocturnal habit may have 

 been acquired as a protective measure. It is necessary here, 

 however, to be guarded in statement, since many factors have 

 to be considered, and consequently every case must be weighed 

 carefully. It is not unlikely, for example, that the nocturnal habit 

 may be a very ancient one, having no special protective signifi- 

 cance, and that its continuance in many recent forms is due to 



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