Megalodon (full name Otodus
megalodon) means "Big Tooth" - a
suitable moniker for what may be the
biggest shark to have ever lived.
This absolute unit grew to be an 
average of 15 meters in length. Its 
razor-sharp teeth were as large as a
human's hand, reaching an average
diagonal length of 18 centimeters.
Because sharks' skeletons are mostly
made out of cartilage, the only 
fossils paleontologists have of 
Megalodon are teeth, vertebrae, and
coprolites. This makes it difficult
to reconstruct what it would have
looked like in life, but we can
assume that it looked like a huge
basking shark or thick great white. 

Megalodon prowled the oceans of
the Neogene Period in subtropical 
and temperate waters. As juveniles, 
they stayed in shallow coastal
environments, but as adults they
preferred deeper water offshore.
Their prey of choice were smaller
cetaceans, and several whale bones 
have been discovered with massive
cuts from Megalodon teeth. They 
competed with predatory whales like 
Livyatan for prey, which is one 
factor that lead to their extinct-
ion. Although popular Shark Week
documentaries claim that this giant 
species might still exist, it is 
impossible that it has survived. 
It was not equipped to dine on the 
larger whales that evolved, it could 
not compete with killer whales, and 
could not take the colder climate.