CHAPTER XXIV 



THE LIZARD : A STUDY OF DRYNESS LOVERS 



In spreading over the land, animals have come into situations 

 where rain falls only for a small part of the j^'ar. In such 

 places not only is the ground usually dry, but vegetation is 

 sparse. Nevertheless, certain animals have come permanently 

 to occupj' even such desert situations, and, indeed, entire 

 genera or families prefer desert habitats. They are the lovers 

 of dryness. The animals most common in our own deserts 

 are certain hard-shelled, black beetles, lizards of many kinds,' 

 the little sphermophiles, looking like slender chipmunks, with 

 now and then a rattlesnake. All of these animals and many 

 others that live and feed on the ground l)urrow into the soil. 

 There they remain during the heat of the day, coming forth 

 at night to feed and seek their mates. These desert animals 

 must go for weeks or even months without drinking water, 

 such moisture as the}^ can get being obtained from roots 

 and green parts of succulent cacti. Almost always the skin of 

 such animals is hard, preventing the loss of internal waters by 

 evaporation. Indeed the whole l^ody of these animals seems 

 to be very dry, and they need only a slight amount of water to 

 live. Even in ordinarily moist climates there is a great deal 

 of difference between animals in respect to their need and love 

 of moisture. AVhile many land animals are found in moist 

 woods and under damp logs, or by the edges of lakes and 



I Fifi. 329. 

 349 



