XIII 



SOCIAL INSTINCTS 



thing more than instinct in these actions, which, if 

 effective, must at any rate be fairly well adjusted to 

 the presence of real danger. The semi-intelligent Para- 

 dise-fish makes a rude nest of bubbles, and is said to make 

 a special provision for the weakly, yet when its young are 

 old enough to fend for themselves it frequently eats 

 them. 1 The highest development of nest-building is 

 found among sticklebacks, to which we have already 

 referred, 2 and we must not forget the conscientious care 

 shown by some species of sharks in fixing their eggs in a 

 safe position. Careful choice of place for oviposition is 

 indeed characteristic of this grade, and some rough 

 preparation may go along with it. Among reptiles, 

 tortoises scrape holes for their eggs, and some measure 

 of care for them is shown by crocodiles, lizards and 

 snakes. All these actions, however, along with the nicely 

 adapted oviposition of many insects, and the choice of 

 suitable spots by cephalopods, we must set down to 

 instinct. More interesting are cases of protection attri- 

 buted to parents in this grade. Thus the cayman is said 

 to defend its young, 3 and the guana to defend its 

 mate. 4 Upon the whole, the parental behaviour in 

 these classes is no higher than we should expect from 

 the general level of their intelligence. The gregarious- 

 ness of fish and other animals in this stage would seem 

 to be purely instinctive, and the alleged instances of 

 attachment too few to lay stress upon. There is little 

 if anything of that close attachment to individuals and 

 many-sided attention to their needs that we find so 

 conspicuously among birds and mammals. 5 



A broad comparison of the different forms of parental 

 care, from its germ to its highest development in the 

 animal world, is given by Schneider. 6 From this it 



1 Brehm, VIII. pp. 187, 188. 



2 See Sutherland, I. p. 36, and a good description in Romanes, p. 243 

 et seq. 



3 Brehm, II. p. 536. 4 Romanes, p. 255. 



5 The summary account of reptile intelligence in Brehm's Thierleben 

 (VII. pp. 24, 25) states explicitly that their care for the young is not 

 to be compared with that displayed by birds and mammals. It is "meist 

 wohl nur Folge eines mit der Geschlechtsthatigkeit zusammenhangendes 

 Reizes " a significant description, 6 Op. tit. p. 372 el seq. 



