THE CONQUEST OF THE DRY LAND 217 



become longer and thicker at the beginning of 

 winter, and the hairs fall out again in spring. 

 The same kind of animal may have a thicker 

 or a thinner coat according to the temperature 

 of the region in which it lives. The tiger, for 

 instance, is perhaps commonest in the hot 

 jungles of India, but the same species spreads 

 far north to very high-lying and very cold 

 regions, and tigers living in the north have 

 much thicker and longer-haired coats than those 

 in the south. 



A very effective way of meeting the dangers 

 of a cold winter after a warm summer is to 

 avoid them by going to sleep. This is called 

 hibernating, and there are many degrees of it. 

 The squirrel, the dormouse, the marmot, and 

 many others fall into a light slumber in their 

 nests beside the heap of nuts and fruits they 

 have laid in, but they wake up and have a meal, 

 and even gather in a few more stores whenever 

 the sun is bright and the day warm. 



We may take as an example of the heavy 

 sleepers our common British hedgehog. When 

 winter approaches he chooses a hole in an old 

 wall, or under a hedge, or among tree roots, 

 fills it with withered leaves, buries himself 

 among these, rolls up into a tight ball, and goes 



