226 THE HAUNTS OF LIFE 
HAUNTS WITHIN HAUNTS 
Until an animal becomes big-brained and 
resourceful, or is endowed with a rich equip- 
ment of inborn gifts which we call instincts, 
or has some special ways of protecting itself 
or effacing itself, the surface of the earth is a 
hazardous home. ‘This makes it easy to un- 
derstand why there should be haunts within 
haunts, such as caves and grottos; why some 
land animals become subterranean burrowers 
and others arboreal climbers; why some have 
returned to the water, like the water-beetles 
and the whales; and why some have sneaked 
inside other animals. 
BENEATH THE GROUND 
Among the first animals to discover the 
world beneath the ground were the earth- 
worms. The strong probability is that they 
originally belonged to a fresh-water stock, for 
several earthworms have gills. When they 
colonised the dry land and became able to 
breathe dry air through their moist skin, they 
must have had for a time a Golden Age. 
Land vegetation had been established, and 
