PRIMEVAL MAN 247 



to trust to speed and vigilance for their safety- 

 there was no longer room for preying beasts 

 of mere prowess. 



In South America it is probable that the 

 heavy fauna died out much later than in North 

 America and northern Eurasia; that is, it died 

 out much later than in what zoogeographers call 

 the holarctic realm. During most of the Ter- 

 tiary period or age of mammals, the period in- 

 tervening between the close of the age of great 

 reptiles and the time when man in human form 

 appeared on the planet, South America was an 

 island, and its faunal history was as distinct 

 and peculiar as that of Australia. Aside from 

 marsupials and New World monkeys, its most 

 characteristic animals were edentates and very 

 queer ungulates with no resemblance to those 

 of any other continent. Toward the close of 

 the Tertiary land bridges connected the two 

 Americas, and an interchange of faunas followed. 

 The South American fauna was immensely en- 

 riched by the incoming of elephants, horses, 

 sabretooth cats, true cats, camels, bears, tapirs, 

 peccaries, deer, and dogs, all of which developed 

 along new and individual lines. A few of these 

 species, llamas and tapirs for instance, still 

 persist in South America although they have 

 died out in the land from which they came. 



