Formidable, elegant and utterly astonishing - sharks deliver some of the most treasured underwater experiences and are one of the most prized encounters for many divers. But despite their incredible evolutionary history, unique behaviours, and countless remarkable adaptations, these creatures are often simplified to little more than a set of teeth. 

Well, that’s all about to change, because here are five facts you probably didn’t know about this incredible species.

And afterwards, why not challenge yourself with our shark quiz?

1. Sharks have a sixth sense

Almost everybody’s heard of the shark’s stellar sense of smell, but did you know they also have a sixth sense? On top of touch, taste, smell, hearing and sight, sharks can also sense electrical fields. Using hundreds of tiny organs on the underside of their snouts, known as the ampullae of Lorenzini, the sharks can detect small electrical signals made by other fish – helping them hone in on their prey. Hammerheads are the undisputed masters of electroreception, boasting a large flat head and plenty of room for extra receptors.

2. They existed before the dinosaurs

Five facts you may not have known about sharks - Greenland shark
Five facts you may not have known about sharks - Greenland shark

Shark fossils have been found dating back to over 400 million years ago, more than 150 million years before dinosaurs roamed the earth. But while dinosaurs are long gone, sharks still roam our waters and are still some of the apex predators - evolution at its finest. And, to put all this into perspective, us humans have only been standing straight and hitting each other with sticks for around 200,000 years.

3. Sharks can only swim forwards

Unlike some other fish, sharks cannot swim backwards because their pectoral fins are unable to curve or rotate. Instead, these fins are more like the wings of a plane, staying firmly fixed in one position. But this is no design flaw, as most sharks use their pectoral fins for balance while their strong tail propels them through the water. And, many sharks require the continuous forward motion to keep water flowing over their gills correctly. 

4. Shark egg sacks are known as ‘mermaid’s purses’

Ever come across a black, leathery pouch all dried-out on the beach? Well, it might just have been a mermaid’s purse.

Five facts you may not have known about sharks - Mermaid's purse
Five facts you may not have known about sharks - Mermaid's purse

While most sharks are viviparous and give birth to live young, some sharks are oviparous, meaning they lay their eggs in small seaweed-like pouches on the seafloor. The baby shark can stay in the pouch developing for up to 15 months before hatching and simply swimming away.

5. Sharks urinate continuously

You may never have given much thought to how - or where - fish go to the bathroom, but sharks are no ordinary fish. In fact, shark’s don’t pee as we know it at all. Their urine is actually absorbed by the flesh, and the urea is used to stop the sharks from 'drying out' and losing water from their bodies to the salty surroundings. Any excess is simply expelled back into the water through their skin or gills. When sharks die, the remaining urea breaks down, making the meat smell and taste of ammonia.

Feeling confident? Find out how much you really know about sharks with our shark quiz!

A Diver's Guide to Sharks

Everything you need to know about these wonderful creatures in a FREE 50 page guide. Read online or download today!