Shark Teeth

I found a shark tooth when I was 12, as I was idly wandering along the sands of my lovely Port Phillip Bay. There are still plenty more teeth out there!

Most of these teeth have emerged from eroding coastal cliffs where they have been locked away as fossils for many millions of years. Rich fossil deposits are found in a number of coastal locations, like the cliffs at Black Rock within Port Phillip Bay.

The teeth most frequently found are from two of the largest sharks of early seas, the massive Fossil Great White Shark, Carcharodon megaolodon, which may have grown to 12 metres or more, and the somewhat smaller Fossil Mako Isurus hastalis. Teeth of the Great White have been found measuring more than 18 cm in length!

The teeth of sharks aren't, as you would expect, attached to the jaw, but are embedded in the flesh, and in many species are constantly replaced throughout the shark's life. When they lose a tooth they will replace it within 7 to 8 days. (If only we could do the same).

All sharks have multiple rows of teeth along the edges of their upper and lower jaws. New teeth grow continuously in a groove just inside the mouth and move forward from inside the mouth in a sort of "conveyor belt" formed by the skin . In some sharks rows of teeth are replaced every 8-10 days, while in other species they could last several months.

The lower teeth are primarily used for holding prey, while the upper ones are used for cutting into it. The teeth range from thin, needle-like teeth for gripping fish to large, flat teeth adapted for crushing shellfish

Identifying shark teeth is difficult. This has a lot to do with the teeth being damaged, worn, and from different species but it gets even more difficult because of the so-called "In-Between Teeth". These are teeth that are from a shark species that was evolving into another, different species.

Get yourself a book on sharks teeth , such as Fossil Shark Teeth of the World and attempt to identify it yourself. (You can always ask an expert at your local museum).

The most common and most referred to "In-Between Teeth" are those from what is believed to be an unusual form of great white shark. These Great White shark transitional teeth are often characterised for their wide crowns, and the way the serrations fade - more pronounced near the root, and disappearing close to the tip of the tooth.

Because of their transitional state, these teeth are extremely rare and, as such, prized by collectors and museums. Best of luck!