CHAPTER IV 

 THE FOOD OF ANIMALS— CARNIVOROUS BIRDS 



Birds present many interesting arrangements connected with 

 the capture of different sorts of Hving prey, pursued on or in the 

 ground, in the water, or in the air. A familiar negative character 

 of these animals is the absence of teeth, a character which, as we 

 have seen, is shared by some Mammals. Birds, however, were 

 not always toothless, the most ancient fossil forms known being 

 comparatively well off in this respect. As a good example we 

 may take Hesperornis 

 (fig. 336), from the 

 chalk rocks of North 

 America, which lived 

 at a time when the 

 dominant back-boned 

 animals were Reptiles. 

 It was a large bird, 

 measuring nearly 6 

 feet from the tip of the 

 bill to the ends of the 

 toes, and its wings 

 were in an undevel- 

 oped condition. This, 

 however, was fully 

 made up for by the 

 powerful legs and feet, 

 which made it an ex- 

 pert diver and swimmer, while the long bill, probably sheathed 

 with horn at its tip, was armed with numerous simple pointed 

 teeth, placed in grooves, and with their points directed backwards. 

 Hesperornis undoubtedly lived on fish, and its long toothed jaws 

 would be well suited for dealing with prey of that kind. 



Fig. 336. — Head of an extinct Toothed Bird {Hesperornis regalis) 



