THE TRANSITION TO LAND 



389 



mals will change color to match the color of the object upon which they 

 are resting, but experiments show that this is not true. They frequently 

 stay brown when placed on a green background and vice versa. How- 

 ever, they will respond to the color of light which strikes them. In their 

 natural surroundings these chameleons will be green when light filters 

 down through green foliage, but when they crawl out under the open 

 sky, they may turn brown even though they are resting on a green leaf. 

 During breeding, feeding, and other forms of excitement they are nearly 

 always green. The males sometimes puff out their throat which is a 

 beautiful shade of pink when thus extended. 



Photos by Winchester 



Fig. 26.12. Iguanas. At left, one of the green iguanas found in Central and South 

 America. They often weigh as much as thirty pounds and are used extensively for 

 food. At right, the desert iguana found in western United States is small, weigh- 

 ing no more than a pound or so at most. 



The glass snake is worthy of mention because it has given origin to 

 the superstition that snakes sometimes become un jointed in times of 

 danger, only to reassemble themselves and crawl away whole when the 

 danger is past. This is not a snake at all, but a legless lizard. Like 

 many lizards it is able to throw off a part of its tail when greatly excited. 

 This is a protective measure; if it is being pursued by an enemy the tail 

 will most likely be caught first. The tail may be broken off and the 

 main part of the lizard escapes while its enemy is satisfied with the tail. 



