Here is what I think happened.

This is a "staged picture"
The horse is not his, the pelts are not his
and the rifle is not his.
Often in the old times the photographer had
all the items, and I feed the lever is not on the
gun and the gun can not be made to fire.

Mike

p.s. sometimes EVEN the horses were stuffed props

USAF RET 1971-95 [Linked Image from jpgbox.com]