260 



A YEAR IN SCIENCE 



We breathe about 15 times a minute. Our temperature 

 is 98.5 F., while that of birds is from 100 F. to 110 F. 

 The migrating and nesting habits of birds afford 

 much interest to man. The song and beautiful plumage 

 give us much pleasure ; there is also no doubt that birds 



are of great value to 

 man in the destruc- 

 tion of insects which 

 destroy plants. 



Reptiles. To this 

 group belong snakes, 

 lizards, turtles, and 

 crocodiles. Such ani- 

 mals are character- 

 ized by the covering 

 of scales or plates, 

 they breathe by 

 means of lungs, they 

 lay eggs very similar 

 to those of birds, and 

 they are cold blooded 

 animals. By that 



we mean that the blood is not always warm as it is in 

 mammals or birds. 



The members of this group differ greatly among 

 themselves. The turtle is peculiar in having the body 

 covered above and below by a thick shell composed of 

 plates. This affords an excellent place for retreat in 

 case of danger. Like the turtle, the lizard has four 



Copyriglit Henry G. Peabody. 

 Fig. 116. Humming bird feeding 

 young-. 



