Page:Through the Brazilian Wilderness by Theodore Roosevelt (1925).djvu/171

 and wedge shape enable them to go at speed through very dense cover. They try to stamp on, and even to bite, a foe, but are only clumsy fighters.

The tapir is a very archaic type of ungulate, not unlike the non-specialized beasts of the oligocene. From some such ancestral type the highly specialized one-toed modern horse has evolved, while during the uncounted ages that saw the horse thus develop the tapir has continued substantially unchanged. Originally the tapirs dwelt in the northern hemisphere, but there they gradually died out, the more specialized horse, and even for long ages the rhinoceros, persisting after they had vanished; and nowadays the surviving tapirs are found in Malaysia and South America, far from their original home. The relations of the horse and tapir in the paleontological history of South America are very curious. Both were, geologically speaking, comparatively recent immigrants, and if they came at different dates it is almost certain that the horse came later. The horse for an age or two, certainly for many hundreds of thousands of years, throve greatly and developed not only several different species but even different genera. It was much the most highly specialized of the two, and in the other continental regions where both were found the horse outlasted the tapir. But in South America the tapir outlasted the horse. From unknown causes the various genera and species of horses died out, while the tapir has persisted. The highly specialized, highly developed beasts, which represented such a full evolutionary development, died out, while their less specialized remote kinsfolk, which had not developed, clung to life and throve; and this