The Making of Species 



seems to us that before this check all other 

 checks pale into insignificance. 



Darwin failed to notice the potent effects of 

 damp. Damp is more injurious to most species 

 than even cold or drought, as every one who has 

 tried to keep birds in England knows. All en- 

 tomologists are aware how harmful damp is to 

 insects. Caterpillars seem to take cover under 

 leaves to avoid damp rather than to hide them- 

 selves from birds, since these make a point, when 

 searching for insects, of invariably looking care- 

 fully under leaves. 



It is a well-known fact that a wet winter in 

 England causes much mortality among rabbits. 

 The increase of the rabbit in Australia is usually 

 attributed to the fact that the little rodent has 

 not so many predatory creatures to contend with 

 there as it has in Europe. This is not so. In 

 Australia the rabbit has to fight against eagles, 

 other large birds of prey, carnivorous marsupials, 

 feral cats, monitor lizards and large snakes, to 

 say nothing of the well-organised and persistent 

 attacks of man. 



Were predacious creatures the most important 

 foes of the rabbit it would never have obtained a 

 firm foothold in Australia. Damp appears to be 

 its chief enemy. In Australia this does not exist. 

 Hence the remarkable increase of the species. 

 Stronger evidence it would not be possible to 

 advance of the potency of damp as a check on 



