[null and void]

I don't know if the bison roamed in the hills or if they were exclusive flatlanders.

Horses can out run bison today.

In short bursts. I *think* a bison can run a horse into the ground in the long haul.

The difference between being a sprinter and a marathon runner. Perhaps this difference in "wind" goes with an ability to surive a lower oxygen level.

That's three testable hypothesis. Do bison roam the hills? Can a bison out marathon a horse? -and- Can marathoners get by with less oxygen than sprinters?

[blam]

"In short bursts. I *think* a bison can run a horse into the ground in the long haul."

Humans have more endurance than any mammal alive.