The Pukao or top not (hat) symbolises additional status associated with the person that the Moai was built to honor. They are carved from scroria and may have been added to the Moai after it had been erected. The Rapa Nui carved a dent in the Pukao so that it would sit upon the head of the Moai. A number of these Pukao have not survived or have fallen off as they get older and worn by the elements.
