198 A PHILOSOPHER WITH NATURE 



Darwin had noticed this habit in the sheldrake, 

 and had attributed it to degraded reflex action 

 an instance, in short, of " an habitual and purpose- 

 less movement " in a changed environment. The 

 sheldrake, it appears, in its natural haunts feeds on 

 worms found in the sands and mud left uncovered 

 by the tide. When a wormcast is discovered, it 

 begins patting the ground with its feet, dancing as 

 it were, over the hole, " and this makes the worm 

 come to the surface." Hence the association of 

 the stamping movement with its impatience for 

 food on being fed. This may be ; but one would 

 have thought better of the worm than that it should 

 come out to be eaten on such an invitation. It 

 might even be considered that natural selection 

 would in its turn have developed the worm's intelli- 

 gence so that it would have recognized so obvious 

 a challenge from its enemy as an unmistakable 

 danger-signal. Despite the great authority of 

 Darwin, it seems reasonable to conclude that the 

 young sheldrake's habit is related to its instinct or 

 intelligence in stirring up the water so as to see 

 its food in the muddy estuaries which form its 

 natural haunts. 



In the case of young animals all the old dispute as 

 to where the border-line is to be drawn between 

 reflex action and instinct, and again between instinct 

 and reason, comes up, but with many new aspects. 

 There is no doubt that young animals possess a 

 remarkable kind of knowledge of the world which 

 they afterwards lose to a great extent. It is often 

 offered as one of the explanations of the unexplained 

 problems of bird migration through vast distances 

 that the young birds learn the way through travel- 



