Modern whales may have reached their massive size today because of the ancient die-off of a giant Megalodon shark.

According to BBC News, the Carcharocles megalodon was the largest shark ever known to swim the sea and it went extinct some 2.6 million years ago. Growing as long as 60 feet, the beefed up great white shark preyed on baleen whales.

During the time of the Megalodon, the whales were considerably smaller, but as the giant predator died off, so did the whales grow.

Catalina Pimiento, of the Florida Museum of Natural History, and Dr. Christopher Clements, of the University of Zurich, collaborated on the study published in the journal PLOS One.

"We are not sure how the mechanisms work," Pimiento told BBC News. "When we found out when that happened, we noticed it coincided with the pattern mentioned in whales. Now we need to find out if one event - Megalodon's extinction - caused the other - evolution of gigantism in whales."

There was no explicit evidence that the Megalodon fed on the baleen whale, but their fossils are often found alongside the shark's teeth. The gradual increase in the whales' size can also be easily explained by the sudden absence of their biggest predator.

Baleen whales now belong to the same animal family as the blue whale, which at nearly 100 feet in length is the largest known animal on the Earth.

"From modern sharks, it is known that larger individuals have a broader range of prey size, including larger prey," Pimiento said. "That means that the larger prey will be predated mostly by larger sharks."

Megalodon remains are not exclusive to one part of the world, but one thing can be certain regarding them, they would have been quite the imposing predator. Their bite could produce about 11 to 18 tons of force and their longest teeth measured up to seven inches.