230 THE HAUNTS OF LIFE 



situation, but, as a matter of fact, getting up a 

 tree has often meant a progressive step in the 

 history of animal life. It opens up new 

 possibilities of movement, of feeding, of nesting, 

 and so forth, and it is a portal which many 

 different kinds of animals have tried to enter. 

 Even earthworms have been found up trees, 

 and the land-leeches often drop from the 

 branches. Many insects and spiders are 

 arboreal, and the Robber-Crab climbs the 

 coco-palm for nuts. The skip-jack, Perioph- 

 thalmus, climbs on the roots of the mangroves, 

 and there are many tree-toads. Among reptiles 

 there are arboreal lizards like the chamaeleon, 

 so admirably suited to the branches in having a 

 prehensile tail and both its hands and its feet 

 cleft into two halves for gripping purposes. 

 Then there are green and agile tree-snakes. 

 Many birds and mammals are strictly arboreal, 

 and, in the case of monkeys, the perfecting of 

 the arboreal habit has led to the emancipation 

 of the hand. For when the fore-limb was no 

 longer needed as a supporting member, it 

 became an instrument for touching and grasping, 

 for handling and lifting. And when monkeys 

 got a free hand they also got a nimbler brain. 



