108 THE FAUNA OF 
pig-like animals differ from those ungulates which live 
on hard ground in the greater number of functional 
toes, in the way in which these toes spread out to pre- 
vent the animal sinking in the mud, and in the absence 
of the elaborate arrangement which enables a sheep 
or an antelope to swallow large quantities of partially 
masticated vegetable food, which is regurgitated and 
thoroughly masticated later, when the animals feel 
themselves relatively safe from pursuit. 
Among the odd-toed ungulates the tapirs, both the 
Malayan form and those occurring in South America, 
are forest animals, haunting much the same regions as 
do the pigs. The great enemy of the American forms is 
the jaguar, and the fact that when attacked the animals 
endeavour to reach thick cover suggests that the forest 
habitat is partially determined by the need for protec- 
tion. As in the case of the pigs it is probably partially 
determined also by the need for finding relatively soft 
and succulent food, for the teeth of pigs and tapirs 
have not the elaboration of structure found in the more 
highly differentiated ungulates. 
The rhinoceroses show somewhat different conditions 
in regard to habitat, for while some haunt more or less 
open plains, others, like the Javan and Sumatran 
rhinoceroses of South-East Asia and the common 
rhinoceros of Africa, are found in forested country, and 
subsist largely on leaves and twigs. Horses are not 
forest animals. The elephants, on the other hand, both 
Indian and African, are found in dense jungles, but in 
both cases this seems to be largely on account of the 
animals’ great intolerance of heat, for they emerge 
into the more open regions both at night and during 
the cooler parts of the day. 
Among the rodents, the squirrelgand flying squirrels, 
