There's evidence that our Igorot ancestors repurposed human jawbones and used these as handles for gongs. This practice had been mentioned in historical records from the Spanish period. Recent/modern historians like Albert Ernest Jenks and William Henry Scott also cited the practice in the books they've written about Igorot/Cordillera history.
There's also an abundance of photographic evidence. Just like this photo taken between 1904 and 1920. The photo shows two Igorot men holding gongs, the handles of which were made from human jawbones. The theory is that these jawbones were taken from the heads of slain enemy tribes. It's a historical fact that our Igorot ancestors used to practice headhunting.
This photo is from the Graphic Arts Collection of the Firestone Library of Princeton University. The caption for the photo stated: "Two Igorots with gongs. The gongs are used on which to beat time for their dances. Note that the handles are human jawbones from the heads of enemies taken in battle. The upper portion of the skull is given a place of honor in the home of the captor."
