Mystery object: Long in the tooth

Identifying obscure and bizarre objects is all in a day’s work for staff in the Queensland Museum Discovery Centre! Today Kieran Aland joins us to share his mystery object of the month.

This object came from the Torres Strait. It was gift from a family friend. It is remarkably heavy and shows a polished surface where it has been exposed to use, forming a sharp chisel edge. It is made of a material called ‘dentine’, which indicates that it’s a tooth of some kind, and is hollow at the base. What might it be? A tusk of a hippo or pygmy elephant, perhaps?

The mystery object is slightly curved, with one end forming a sharp, chisel-like point. Photo: Kieran Aland.
Another view of the mystery object. The flat part of the ‘chisel’ end appears polished.
The other end of the object is hollow. Photo: Kieran Aland.

The answer

Our mystery object is actually a tusk from a Dugong (Dugong dugon). These are found in the upper jaws of adult male, and some older female, Dugongs.

The skull of a Dugong. The tusk is held nearby to show its orientation in the skull. Photo: Kieran Aland.

The Dugong is a large herbivorous marine mammal. Along with the manatees (three species) of the Americas and West Africa, the dugong is a living member of the order Sirenia. Dugong are easily distinguished from Manatee by the shape of the tail. Manatee have a paddle-shaped tail whereas Dugong have a tail with two distinct flukes, much like the tail of cetacean mammals (whales and dolphins). Dugong can be distinguished from similarly sized dolphins by the forward position of their paired nostrils. The dolphins have a single blowhole located on the top of the head.

Dugongs are one of the few living marine mammals that are predominantly herbivorous. Photo: Gary Cranitch, QM.

Two of the three Manatee species (the West African Manatee and the West Indian Manatee) have fingernails on their flippers, reminiscent of the toenails of Elephant. Toenails, tusks…..It is no surprise that the Sirenians are distantly related to the Elephants. The tusks of elephants are also in the upper jaws and these extended teeth have often been observed to perform a variety of functions. Although the function of the tusks of Dugongs has not been confirmed by observation, a social function has been proposed. A common type of scar that can be seen on male and female adult Dugong appears to have been inflicted by individuals with tusks. Like the tusk of Elephant, the tusks of Dugong are composed of Ivory. Ivory is essentially dentine, unprotected by a covering of enamel and produced by very few species of mammal.

Visit the Discovery Centre on Level 4 of the museum

Visit the Discovery Centre to see this Mystery of the Month this January. Do you have an interesting question or mystery object? Our helpful and knowledgeable staff can answer your questions through our Ask an Expert inquiry service.