Mithadan,
And the funniest thing of all is that the Central American tapir species at least (the biggest of all of them) can be easily domesticated - there were such experiments back in 60-70s. They even let people make them to draw a plow in a field. And they strong enough for this, strionger than a horse anyway.
But the native American seems to have been too wastefull towards the unique biota of the New World - they did not domesticate any of 9 (!) species of native American horses and asses - they simply exterminated them while populating the continents for food. The same - with other creatures.
Actually the Incan llamas were the only successful domestication event in the New World (except guinea pigs and some pounltry). Enven though the New World animals are generally more tolerant towards humans the those of the Old World.
Btw, - once there was one very interesting thing when the anscestors in Incas tried to domesticate anothre creature - they kept giant ground sloth (not the biggest species though, just one the size of a big bull) in a cave in fed him. But it eventually faild some 7 000 yoears B.P. And the species went extinct, too...