190 THE HAUNTS OF LIFE 
There is another reason why it is not easy to 
think of land animals beginning on the dry 
land; the conditions of life are too difficult 
for beginners or apprentices. This will become 
clearer later on, but it may be noticed that 
breathing and moving, and the disposal of the 
eggs or young, are much more difficult on land 
than in the water. As it is much more difh- 
cult to escape from enemies when movement 
is all in one plane, we cannot wonder that 
many land animals have become burrowers, 
and other climbers, and others fliers, that 
others have become camouflaged, and that 
others have taken to coming out at night only. 
But we shall return to this subject later on. 
ORIGIN OF LAND PLANTS 
When we consider the sand-dunes, the rocky 
islands, the deserts, the mountain-tops, and so 
on—we feel at once that there are many parts 
of the dry land which cannot be called very 
hospitable to living creatures. The dry land 
is a haunt very much more difficult than the 
sea or the lake. The fact is that no great 
colonisation by animals was possible until 
plants had prepared the way. They provided 
