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 
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