>
> << It is difficult for us to determine specifically the body composition
of
>  Pleistocene megafauna such as the giant ground sloth and the mastodon.
>  Humans hunted both species into extinction during the Late Pleistocene >>
>
 Is this a fact  or speculation

I think most anthropologists/archaeologists agree that the megafauna were
hunted to extinction when early men began hunting with wolves, then dogs.
No animal could survive their combined efforts.  Early people had all sorts
of methods of killing large numbers of animals at one time:  running them
off cliffs, running them into canyons, funneling them into man-made "V"
shaped enclosures, etc.  The "take just what you need" philosophy didn't
seem to apply in really early hunting.

That said, I just finished reading, "Horse, Follow Closely" about
traditional Native American horse training.  The author, a Native American,
says it isn't known why the megafauna disappeared.

Kath