THE TROPICAL FOREST 103 
air is less complete than in the insect-eating forms, the 
arrangement of the tail apparently preventing them 
from giving those sharp turns so necessary in an animal 
which feeds on insects caught on the wing. Further, 
as the fruit-bats feed in trees they are more arboreal in 
habitat, being able to scramble about the trees, attach- 
ing themselves by the hind feet, and by the strongly 
hooked thumb of the hand. Similarly the index finger 
is not reduced to the rudimentary condition seen in 
other bats, where it is useless, and is here usually fur- 
nished with a claw. Fruit-bats spear their food with 
the claw of the thumb, and have teeth so modified as 
to allow them to crush pulpy fruits. From the diet 
the animals must necessarily have been once confined 
to regions where wild fruits were abundant, but, like 
some members of the order Primates, they have taken 
advantage of man’s fondness for fruit to extend their 
range to regions where his plantations can be robbed. 
In Australia, where wild fruits are somewhat rare, the 
fruit-bats seem to devour the flowers of the eucalyptus, 
but the way in which they raid the orchards of the 
fruit-growers shows that fruit is greatly preferred when 
it can be obtained. 
In the forests of tropical America there occurs an 
interesting family of bats, the Phyllostomatidae, or 
vampire bats, some of whose members present a curious 
analogy to the fruit-eating bats of the Old World. The 
vampire bats belong to the insect-eating section (Micro- 
chiroptera) of bats, but nevertheless some of them eat 
fruit only. Others eat fruit and insects, while others 
again are purely blood-suckers. 
We have already pointed out that insectivores are 
peculiarly helpless animals, without the intelligence 
which enables many of the Primates to escape from 
