The Red Hunter: Too Humane to Kill - Indians were probably the first conservationists. Indian methods of hunting buffalo aided the process of natural selection, since only the old, tired, and sick animals ran slowly enough for the Indians to catch up with them. In winter, if a starving buffalo found itself separated from the herd and almost buried in a snowdrift, any Indian who happened on it would be quick to put it out of its misery. A favored hunting technique was to stampede the buffalo herd up to the edge of a cliff, leaving it up to each individual buffalo to decide whether or not to jump -- further evidence of the Indians' high regard for animal life. The Indians, unwilling to slay any living being, would chase a deer into the water, then follow it in their canoes, hoping it would drown before they could spear it.

from

The American Indian:
Noble Savage or Renaissance Man?

by Anne Beatts

National Lampoon, Jan. 1972, "Is Nothing Sacred?"

"Unlike us, the Indian left the land as he found it. Experts have estimated that in order to survive at a subsistence level, the average Indian needed only 33,000 acres of land...."