Sharks have always scared the bejesus out of me. Growing up near a beach in Australia will do that to you: we have more human fatalities from sharks than any other country. Every summer, our news channels focused on gruesome shark attacks, even though, in reality, there were very few. Little did I know that one day I’d become a scientist working on shark research.
The International Shark Attack File, kept at the Florida Museum of Natural History, is a global record of “negative human-shark encounters,” incidents where humans have been harmed or killed by sharks. In 2023, only 10 deaths were caused by sharks, far fewer than the hundreds of human fatalities in North America caused by “negative human-deer encounters.”
Following the 1975 release of Jaws, more than half the great-white-shark population of the North Atlantic was brutally killed by people high on the dangerous cocktail of fear and ignorance. Yet when the movie premiered, we knew almost nothing about the biology of great whites.
Scientists only recently learned that the North Atlantic white-shark population takes a long time to sexually mature—26 years for males, and 33 years for females—so population recovery takes many decades. It also turns out that great white sharks use the sun as their hunting guide (research has proven they prefer to seize prey when the sun is behind them) and that a moderate-sized shark can kill a much larger humpback whale with just a few carefully targeted bites.
In 2023, only 10 deaths were caused by sharks, far fewer than the hundreds of human fatalities in North America caused by “negative human-deer encounters.”
Sharks are older than the rings of Saturn. An early species first appeared about 465 million years ago, long before trees or insects. Around 110 million years ago, when dinosaurs ruled the earth, lamniform sharks, a large, predatory shark group that included white sharks, emerged. At this time, sharks were second-rank predators bowing down to gargantuan killer marine reptiles, such as pliosaurs and mosasaurs, some of which spanned 60 feet long and had banana-size teeth.
Chaos erupted when a seven-mile-long asteroid smashed into Mexico about 66 million years ago, wiping out most life on the planet, including the dinosaurs and the giant marine reptiles. Carchariniforme sharks (think bull sharks and tiger sharks) arose out of this mass extinction.
The lamniform sharks were not completely gone. They spawned one of the greatest predators of all time, Otodus megalodon, or the megalodon. Reaching around 66 feet long and weighing up to 65 tons, these killers had six-inch-long teeth. New research shows they were warm-blooded, with temperatures of around 81 degrees, which means they could go into higher, colder latitudes than most sharks.
The first white-shark ancestors appeared in our oceans about 30 million years ago as enormous, robust mako sharks. Some grew 30 feet long and foraged in megalodons’ shadows. Then, about six million years ago, they began developing teeth with weakly serrated edges. When their teeth eventually became coarsely serrated, our modern white-shark species was born. After oceans suddenly cooled around 2.6 million years ago, the megalodons went extinct, giving the white sharks free rein as the apex predator.
Sharks are older than the rings of Saturn.
In January 2023, I went cage diving to see white sharks in the wild near the Neptune Islands, off South Australia. Not long after we anchored, a large white shark began circling our boat. I backed slowly into the swaying metal cage suspended in the water.
At first, I feared the shark would attack the cage and destroy it to get to me, exactly what happened in the terrifying Jaws cage scene filmed in nearby waters some 50 years ago. But once I settled into the cage, I began to relax, watching the shark swimming around me. It was far more interested in the fish bait thrown out to lure it than my presence. I was in awe of its powerful, streamlined body and its rapid acceleration as it burst through the water. I witnessed its massive jaws open and thrust forward, flashing serrated, triangular teeth.
Sharks are being hit hard by overfishing, pollution, and climate change. Many species are now classified as threatened or vulnerable. Recent surveys prove that shark populations are rapidly declining in most reefs, which they help keep viable by eating fish that eat the coral. If we can understand sharks better, we will have a better chance at keeping some of the world’s toughest predators—and maybe save our oceans.
John Long is the strategic professor of paleontology at Flinders University, in Australia, and the author and co-author of several books, including Feathered Dinosaurs, The Dawn of the Deed, and many more
