Fossilised shark tooth. This huge tooth belonged to Carcharocles megalodon, the largest shark to have ever lived on Earth. This shark ate whales and other big sea animals and could grow to a massive 20 metres long and 60 tonnes in weight. It lived mainly in the Miocene epoch (between around 23 and 5 million years ago) but was extinct by about 1.6 million years ago. Megalodon was originally placed in the genus Carcharodon as it was thought to be a direct ancestor of the modern Great White (Carcharodon carcharias), but evidence now suggests that it was only distantly related, hence its transfer to a new genus (as of 2007). Fossil found in North Carolina, USA.