A portion of the cranial vault is cut away from the top of each skull, and one shows drilled holes for attachment of the mandible. The skulls show a close resemblance to certain Moche ceramic skull jars that have a similar opening at the top of the vessel.
Osteological analysis indicates that both skulls are of young adult males.
Cut marks on the external surfaces of the cranial vault, face, and mandible indicate that they were prepared from fleshed heads and not from dry skulls. The finds at Moche are the first documented examples of this form of cranial modification, although an early Spanish account describes a similar trophy vessel that belonged to the Inca Atahualpa. Comparison of the Moche modified skulls with Nasca trophy heads reveals that the two were prepared and used differently.