The great white shark had two ancestors that were even more impressive...and scary. The "big dawg" was carcharocles megalodon (above), who lived from 3 to 15 million years ago.
Fully grown, C. megalodon was more than 10 times the size of its descendant, today's great white shark.
At 52 feet in length and 52 tons, C-Megs was the largest predatory fish and the second-largest carnivore (after the Sperm Whale, physeter macrocephalus) ever to inhabit our planet. Megalodon teeth can be over 7" long (below, right). As you can see, C-Megs jaw was more than big enough for people to fit into standing up.
Our fossilized C-Megs teeth come from clay and sand formations in the southeast US (Carolinas, Florida).
Today's great white shark, enlarged to C-Megs size
Adult C-Megs tooth...