Police said Tuesday they were going through lists of missing persons in an effort to identify the remains, The West Australian reported. They said the head was that of a Caucasian man between the ages of 30 and 50 who was missing his upper front teeth.
A medical examiner said the teeth had been gone for some time.
The head was discovered by the girl Sunday afternoon at Porpoise Bay on Rottnest Island, about 11 miles off the coast near Fremantle. Her parents called police when they noticed a human ear as they unwrapped the head.
The beach was searched and divers combed the seafloor nearby without finding any other remains or evidence, investigators said. They planned to examine currents in the area and boat movements in recent days.
A further search was planned of an area nearby on Rottnest Island where debris is usually carried.