Is Megalodon Still Alive? What Happened to the Giant Shark

When did megalodon go extinct?

Megalodon lived from about 23 million to about 3.6 million years ago, through the Miocene and into the Early Pliocene epoch. Its teeth have been found on every continent except Antarctica, showing that it once ranged through warm and temperate seas worldwide.

Dating its extinction is tricky, because fossils can be washed out of old rocks and buried again in younger ones. A 2014 study estimated that megalodon disappeared about 2.6 million years ago. In 2019, a team led by paleontologist Robert Boessenecker re-examined the dates of megalodon fossils and found no reliable records younger than about 3.6 million years. Their statistical estimate put the extinction at about 3.5 million years ago, so megalodon vanished roughly a million years earlier than previously thought.

How big was megalodon?

Megalodon had a skeleton of cartilage, which rarely fossilizes, so it is known almost entirely from teeth and a few sets of vertebrae. Its teeth are the largest of any known shark, reaching about 18 cm (7 in) along the edge, compared with roughly 5–7 cm (2–3 in) for a large great white. They are thick, triangular and finely serrated.

Scientists estimate body size by comparing these teeth and vertebrae with living sharks. Estimates for the largest megalodons range from about 14 to 24 m (47–80 ft), depending on the method and the body shape assumed. A 2015 study of 544 teeth suggested that the most common size of megalodon, counting young and adults together, was about 10.5 m (34 ft). Weight estimates for a 16 m (52 ft) megalodon range from roughly 30 to 60 tonnes.

Its shape is still debated. Megalodon was long pictured as a giant great white, but recent studies of a vertebral column from Belgium suggest a longer, slimmer body. Either way, it was one of the largest predators ever, far bigger than any shark alive today that hunts large prey. Living giants are compared in largest fish in the world.

What did megalodon eat?

Megalodon was a top predator of the ancient oceans. Fossil whale bones with deep, megalodon-sized bite marks show that it attacked and scavenged whales, and it probably also ate dolphins, seals, sea turtles and large fish. Its bite force has been estimated at roughly 108,000–182,000 newtons, among the strongest of any animal known.

Young megalodons seem to have grown up in warm, shallow nursery areas. Fossil teeth from Panama, about 10 million years old, include many from small juveniles, suggesting a coastal nursery where young sharks fed on fish and small prey away from larger predators.

Why did megalodon go extinct?

No single cause has been proven, and scientists think several factors combined:

• Cooling oceans. The climate cooled through the Pliocene, and falling sea levels during growing ice ages shrank the warm, shallow coastal waters that young megalodons needed.
• Loss of prey. Many small and medium-sized baleen whales, likely an important food source, declined or disappeared at around the same time. A wider extinction of large marine animals during the Pliocene also hit marine mammals hard.
• Competition. The great white shark had appeared by then and spread around the world. Chemical studies of fossil teeth from North Carolina suggest the two species overlapped in diet, so great whites may have competed with young megalodons for food.

Whatever the exact mix, megalodon was too large and too dependent on rich food supplies to survive the changes.

Why megalodon is not hiding in the deep sea

The idea that megalodon still lurks in the deep ocean is popular in novels, films such as The Meg (2018), and online videos, but it does not fit the evidence.

• Wrong habitat. Megalodon lived in warm coastal and open waters. The deep sea is near freezing and holds very little food, nothing like enough for a giant predator that needed whales.
• No fresh teeth. Sharks shed thousands of teeth in a lifetime. A living megalodon population would leave fresh, white teeth on the seabed, yet every megalodon tooth ever found is fossilized.
• Old claims did not hold up. Teeth dredged from the Pacific seabed by the British research ship HMS Challenger in the 1870s were once claimed to be only 11,000–24,000 years old, based on the coating of manganese around them. That method was unreliable, and the teeth are now thought to be much older fossils.
• Fiction presented as fact. In 2013, a television program called Megalodon: The Monster Shark Lives used actors playing scientists to suggest the shark was still alive. It was fictional, and scientists widely criticized it.

New sea creatures are still discovered, such as the megamouth shark in 1976, but these are mostly modest-sized animals in poorly explored places. A 15 m (50 ft) predator hunting whales would not go unnoticed.

Megalodon vs great white shark

Megalodon was once thought to be a giant ancestor of the great white shark and was placed in the same genus, Carcharodon. Today, most scientists classify it in a separate, extinct family, Otodontidae, whose lineage split from that of the great white more than 100 million years ago. Their teeth look similar mainly because both evolved to cut large prey.

The great white instead descends from an extinct shark called Carcharodon hastalis, which had smooth-edged teeth. The two giants shared the seas for a few million years before megalodon disappeared. How shark teeth are replaced, and why they fossilize so well, is explained in How many teeth does a shark have?, and the deeper history of sharks in How long have sharks existed?