This very old bull roarer was made out of bone by Australian Aborigines. I acquired it from the Barclay Gallery in 1988. I was told that it was probably made out of kangaroo bone, but the flat profile and large size makes me think that it could be from a sea mammal (whale or dungong). One side has a rough texture as you would see on the inside of a mammal bone. The other side is smooth and decorated with incised lines. One end is pierced for the attachment of a string. I have never tried out this bull roarer to see how well it works, but the proportions are correct. I have no idea how old it is. I can usually estimate age if an artifact is made out of wood, but bone does not change much with time. The Barclay Gallery collected this artifact in England, so chances are it was collected in the 19th Century, but it could be much older. A very nice artifact. in excellent condition