I would like to offer one more thing for you to think about. You quoted Edgar Rice Burroughs in chapter nine of Return Of Tarzan saying, "In fact, Tarzan had never killed for pleasure, nor to him was there pleasure in killing."
I would like to point out another quote by ERB, but this time from chapter ten of Tarzan Of The Apes. "He killed for food most often, but being a man, he sometimes killed for pleasure, a thing which no other animal does; for it has remained for man alone among all creatures to kill senselessly and wantonly for the mere pleasure of inflicting suffering and death."
James Michael Moody