What are the differences of a blue whale and a megalodon?

One is a "shark" (ie, a fish) and the other is a mammal! Like a shark the megaladon breathed underwater while all whales (dolphins, etc) have to come to the surface to breath. read more

Well there are a lot of differences between Whale Sharks and the extinct Megalodon. In regards to size the Megalodon was much larger, but the real difference is seen in their diet. Whale sharks are filter feeders who eat small animals like plankton and krill. read more

If the Megalodon Shark were alive today it is very unlikely that any whale or dolphin would be much of a threat or challenge to these animals, except perhaps the killer whale. At lengths of up to 60 ft. long the Megalodon would be twice as large as the killer whale (one of the only cetaceans known to hunt and kill sharks and other marine mammals). read more