Sharks evolved around 450 million years ago, which means they’ve hitched a lift on planet Earth around the galaxy twice. If that’s not yet given you a fact-induced headache, it may tip you over to hear that it also means sharks were on Earth before trees, at a time when Saturn didn’t have rings yet.
Part of their success comes down to their flexibility when it comes to environmental conditions, able to survive in a wide range of oceans and at different depths.
“I think it is safe to say that it is partly because sharks are able to exploit different parts of the water column – from deep, dark oceans to shallow seas, and even river systems,” Emma Bernard, a curator of fossil fish at the Natural History Museum said in a piece for the museum. “They eat a wide variety of food, such as plankton, fish, crabs, seals and whales. This diversity means that sharks as a group are more likely to survive if things in the oceans change.”
One of the longest-living sharks, the Greenland shark, certainly looks prehistoric. We actually only found out that they were capable of living to around 400 years old thanks to the atomic bomb, but the earliest sleeper sharks didn’t emerge until around 100 million years ago, by which time this group of fish had already been splashing around on Earth for well over a galactic year.
Throughout their existence, they’ve taken on some pretty funky morphologies, from the bizarre whorl-toothed Helicoprion, to the warm-blooded mighty megalodon. For a long time, we thought megalodon was a stocky chunk of murder mouth, but a recent study revealed that they may actually have been long and slender predators.
We’re still finding their ancient remains across the world – and while we’ve only got teeth to work from (those damn cartilaginous bones), some of the specimens are quite remarkable. Just check out this manganese-encrusted megalodon tooth that was found at a depth of around 3,090 meters (9,842 feet).
In the ~450 million years they’ve had to get settled, sharks have revealed some pretty unusual behaviors. In 2022, footage captured a shark strolling around on land like it was no big deal. At least nine species of sharks are known to use their fins to move about in shallow water, and some of these make brief jaunts entirely onto land.
So whatever that saying is about old dogs and new tricks, we’re not buying it. Sharks seem to have an endless variety of curious tricks up their fins, including, most recently, possibly knocking up a stingray.
Source Link: Sharks Are 450 Million Years Old, Meaning They Were Here Before Trees