Shark Week 2019: Megalodon's Demise Explored in Josh Gates' 'Expedition Unknown' Special

Shark Week 2019 will kick off Sunday by exploring the history of one of the ocean's biggest rulers, Megalodon. Josh Gates will launch the week-long event with a special episode of his adventure series, Expedition Unknown: Megalodon.

The prehistoric predator Megalodon is believed to be the largest shark to ever exist before it went extinct between 2.6 and 3.6 million years ago. Scientist have estimated the fish grew to be as big as a modern-day school bus—weighing as much as 60 tons and 600-feet in length. While its size put Megalodon the top of the ocean food chain, the cause of the animal's extinction has remained shrouded in mystery.

Shark Week's 'Expedition Unknown' Explores the Demise of Megalodon
One of the world's largest set of shark jaws comprised of about 180 fossil teeth from the prehistoric species, Carcharocles megalodon, which grew to the size of a school bus, is displayed at the Venetian Resort Hotel Casino September 30, 2009, in Las Vegas, Nevada. Ethan Miller/Getty Images

On Expedition Unknown, Gates will attempt to uncover what exactly happened to the massive sea creature. Paleontologists will analyze the only surviving evidence of Megalodon's existence—teeth fossils that have been found in waters and lands around the globe—while marine biologists look at modern-day descendants of the giant sharks to shed more light on what may have caused Megalodon to vanish from existence.

Meanwhile, Gates will go diving in shark-infested waters to understand how Megalodon would have impacted and influenced some of today's biggest predators like the great white shark.

There have been a number of studies on what may have caused Megalodon's demise. More recently, scientists suggested the mass extinction of the enormous fish was caused by a celestial event.

In a 2018 study, published in the journal Astrobiology, scientists linked Megalodon's extinction to a series of exploding stars called supernovas occurring within 150 lightyears of Earth. Researchers argued the galactic explosion likely would have caused Earth to be blitzed with cosmic rays, resulting in the planet being covered with muons—elementary particles that resemble electrons.

Scientists claimed the impact of so many muons—which make up about a fifth of the radiation dose most people received—would have likely caused cancerous mutations capable of destroying 36 percent of the marine megafauna like Megalodon.

Although Megalodon hasn't swum the depths of the ocean in many millennia, people are still discovering giant teeth that may have come from the fish. A North Carolina man discovered a tooth believed to belong to Megalodon in early July, just ahead of the 31st annual Shark Week.

So good we'll ALL scream. #SharkWeek starts this Sunday on @Discovery.

— Shark Week (@SharkWeek) July 24, 2019

Harvey Wall was combing Ocean Isle Beach — about an hour up the Atlantic coast from Myrtle Beach, South Carolina — for seashells when he claimed he stumbled upon the gigantic tooth. "I was surprised [it was there]," Wall told WECT-TV. "We were looking for seashells and walking our dogs. I could only see the black part in low tide. I kicked it and it flipped over, exposing the whole tooth."

The tooth has since been donated to the local Museum of Coastal Carolina.

Expedition Unknown: Megalodon airs during Discovery Channel's Shark Week on Sunday at 8 p.m. ET.