18 CONTROLLED NATURAL SELECTION 



that position. Animals in defence, in order to 

 beat off an enemy, will erect combs, feathers, 

 or hairs, will open mouths, stretch necks, take 

 up an upright position, and in many other 

 ways assume conspicuous attitudes ; these 

 may be called Eepelling Conspicuous Atti- 

 tudes. Just as there are attracting conspicuous 

 movements, so there are attracting conspicuous 

 attitudes. Many animals by thus making them- 

 selves conspicuous endeavour to draw an 

 enemy's attack, for instance, from their young. 

 Birds especially will erect combs, spread tails, 

 and assume all manner of conspicuous attitudes 

 for this purpose. A large number of pre- 

 copulatory displays consist in the assumption 

 of conspicuous attitudes. 



Sound. Sound is seldom used for ought 

 but signalling to friend or foe. Silence spells 

 concealment, sound conspicuousness. 



Sound can be similarly classified : 



Purposely 



conspicuous ^ 



sounds. 



1. Signals to (() Between the aex* 



- . , i (o) Between members or other 

 I societies. 



2. Signals to 

 enemies. 



(a.) Repellent 

 sounds : to 

 enemy away. 



(b) Attractive 



(conspicuous) 

 frighten 



an 



(conspicuous) 



sounds : to attract an enemy, 

 to draw its attack. 



