15 RARE AND UNUSUAL SHARK SPECIES

Did you know there are over 500 species of shark? Here are 15 rare and unusual specimens to haunt your dreams.

The oldest vertebrate (that's an animal with a spine) species on Earth is the Greenland Shark, with lifespans estimated at 300-500 years. No jokes! This 6.4-metre, 1,000kg apex predator lives in the waters of the North Atlantic and Arctic oceans and will eat anything that gets too close.

Although they've never been recorded hunting, their diet comprises of fish and smaller sharks. But, according to Wikipedia, "Greenland sharks have also been found with remains of seals, polar bears, moose, and reindeer (in one case an entire reindeer body) in their stomachs."

Luckily for humans, the waters that they populate are too cold for us to swim in, so there have been no recorded deaths of a human by the Greenland Shark. They're also scavengers and love the smell of rotting flesh, so they'll often gather around fishing boats for an easy meal.

On the more unusual side of the shark-spectrum is the now extinct Helicoprion Shark, seen in the picture above. Technically, it's not actually a shark, more like a cousin from the cartilaginous fish family.

Either way, this ancient fossil had a rather unusual mouth. The head is said to be similar to that of the modern-day Goblin Shark, with a long and narrow skull, but the upper jaw had no teeth. It's the lower jaw though that is fascinating. Made up of a "tooth-whorl", it looked very much like a circular saw, with just one set of teeth in the middle facing into the mouth.

Two of the fossilised tooth-whorls that have been found suggest these fish, who lived over 290 million years ago, could grow over 12 metres long. That's twice as large as a Great White! Fossils have been found From Western North America and the Canadian Arctic to states in the US from Idaho to Nevada, Texas and California, as well as the Ural Mountains of Western Australia.

With so many interesting facts to learn about our sharp-toothed fish friends, this video will teach you all you need to know about 15 rare and unusual shark species. That should be enough to scare your friends with, so go on, press play and enjoy the show!