ADAPTABILITY OF LIFE 



529 



RATTLESNAKE COILED READY TO 



The color of these reptiles makes them 

 hardly distinguishable from the sur- 

 rounding desert. 



or, like the camel, are 

 able to travel for long 

 distances without water. 

 In the colder regions 

 the plants have the power 

 of rapid growth and 

 germination during the 

 short season when the 

 snow has melted away. 

 Then, during the long 

 winter, they lie dormant but unharmed under the snow and 

 ice. The animals are either able, like the reindeer, to live 

 upon the dry mosses, lichen, and stunted bushes, or else 



upon other animals. 

 Their color, like that 

 of the polar bear, 

 often blends with 

 their surroundings. 



Some animals have 

 a wide range of 

 adaptability, like the 

 tiger, which is found 

 from the equator to 

 Siberia. But usually 

 the range of an ani- 

 mal species is much 

 more restricted, since 

 it is seldom able to 

 adapt itself to widely 

 differing conditions. The surrounding region, the eleva- 

 tion, the temperature, the amount of moisture, the soil, 

 the kinds of winds and their force, all have a marked 



A HERD OF REINDEER 



This animal is of invaluable service to man 

 in polar regions. 



