They hunt heads of those from other tribes! I remember when I was a kid and we visited my parents' hometown (which they left since they got married), my mother was scaring me of not going astray because head hunters might get me. I first challenged her that it is not true but she said it is. Years after that, I remembered that conversatio  and asked her if it was true. She said yes but that was before world war II and  not in their hometown but in nearby provinces. She said somehow tribespeople learned to value life of others even if they are from other tribes for as long as there is no stealing of properties between tribes.