The mythological concept of the Iatmul is strongly influenced by the idea of a close connection between past and present. Because of this concept, the community consists of both the dead and the living and this is the reason why ancestors play a central role within the social and cultural sphere. The living owe their origins and knowledge to the ancestors. In addition, they possess magical powers that can be used against them in order to harm or to punish descendants. Especially by means of the preparation and storage of skulls, it was hoped to be able to draw on the magical powers. At the same time, such powers were also attributed to the deceased of head hunts.
The procedures for making ancestor skulls and headhunting trophies differed fundamentally at first. If the deceased was a member of the community, the skull was carefully removed from the exhumed body only after a few weeks, cleaned and dried in the sun for a few days. In contrast, skulls from headhunts were boiled in water and cleaned immediately after returning to the village. The soft parts were removed and then buried. The skull itself was either dried in the sun or smoked over the fire in the men's house for several days.
In the next production steps, the materials used and the modelling techniques do not show any differences. The modelling clay was mixed from reddish clay, tree oil and burnt lime or pumpkin pulp. Then the mass was applied to the skull and the eyes, nose, mouth, chin and ears were shaped as realistically as possible. The face area was painted with wavy lines of white, red and black. Instead of the eyes, cowrie shells were placed and the original head hair was worked into the mass at the back of the head.
The appearance of ancestor skulls and head hunting trophies is exactly the same, so it is difficult to distinguish between them in their final design. Furthermore, ancestor skulls were kept in the dwellings. Either they were placed on their own holders, put on wooden headless figures or wrapped in specially designed net bags. In contrast, skulls of headhunting victims were lined up as prestige objects in the men's house