Carchardon megalodon (meaning 'Rough tooth, big tooth) was the ancestral big daddy of the modern great white shark. It lived in prehistoric oceans sometime around 20 to 50 million years ago1 and ruled its marine domains until it became extinct a mere two million years ago. Some experts believe that megalodon did not become extinct until as recently as 10,000 years ago.
Megalodons almost certainly lived in warmer waters, and lived on large fish and small whales. Their decline may be attributed to climate changes; it is also likely that the fast biological development of their main food source made it more difficult to catch sufficient of them to survive.
No fossil megalodon skeletons have ever been found, except for an occasional vertebra, because shark skeletons consist of cartilage and not bone. Cartilage decomposes long before it can fossilise.
However, megalodon teeth provide an excellent indication of the size of these fearsome creatures. They were the largest predators that ever lived on land or sea. If you could place a fully grown megalodon upright on its nose, it would be at least as tall as a six-storey building: 65 feet (20 metres) high.
Megalodon teeth can be up to eight inches (20cm) long. They are covered in tiny serrated 'teeth' and weigh up to a pound (half a kilo). Compare this with the largest teeth of the great white shark, which measure three inches (eight cm) and weigh but a few ounces.
Fossil megalodon teeth are collectors' items and fetch very high prices if they are in good condition. Teeth in pristine condition are rare; a few million years take their toll. Collectors will pay up to a thousand dollars for a six-inch megalodon tooth that still has its enamel and all its serrations. The colours of these teeth are interesting; the tooth becomes impregnated with minerals from the sediment in which it fossilises and can be practically any colour, from a dingy grey to blue, red or orange.
Complete jaws have been created from fossil remains and teeth, and can be seen in many natural history museums. Standing before a gaping set of megalodon dentures through which you could drive a truck without scraping the paint certainly makes one very happy that two million years separate us from these monsters.