20 Things You Didn't Know About Sharks

Great White Breaching for Decoy — Image Courtesy of Chris Fallows – apexpredators.com

We love sharks here at The Scuba News and here are 20 things that you may not know about this beautiful, majestic creature!

Sharks only view the world in black and white because they only possess a single type of “cone” photoreceptor, compared to humans who have 3 types of photoreceptor, giving us trichromatic colour vision.
Unlike most sharks (that have few offspring), whale sharks can carry more than 300 pups at a time.
Tiger sharks help to keep seagrass beds healthy by preventing turtles from overgrazing.
Sharks have been swimming in the ocean for more than 400 million years, and the Port Jackson shark is one of the oldest species still alive today.
Some sharks are able to store sperm and give birth to pups from different fathers (in the same litter).
White Tip Reef Sharks (Triaenodon obesus) often chase their prey into small rock crevices and jam their body in afterwards, preventing it from escaping.
There is no such animal as a shovelnose shark or guitarshark. They are, in fact all shovelnose rays.
Baby Bamboo Sharks mimic the appearance of poisonous sea snakes to deter potential predators.
Shark meat contains higher levels of toxic mercury than any other fish.
The Greater Spotted Catshark (Schliorhinus stellaris) is also known as nursehound, bull huss, dogfish, flake and many other imaginative names.
Sharks have good night vision thanks to a membrane in the back of their eye called the tapetum lucidum. This makes them more sensitive to light by reflecting sunlight back into the retina.
The unique head shape of Hammerhead Sharks makes them better hunters because their electroreceptors are spread out over a larger surface area, allowing them to detect prey from a greater distance.
Due to overexploitation and lack of proper management, many shark species are under considerable rick of unrecoverable decline. It is estimated that sharks are being killed at an alarming rate of 273 million worldwide per year.
Bamboo sharks are often referred to as “walking sharks” as they can use their fins to “walk” along the seabed.
The Zebra shark is so-called because as a juvenile it has distinct white stripes across its body, which change to dark spots as it matures.
White sharks can live for 50+ years and take approximately 16 years to reach sexual maturity.
Globally, up to 7.9% of sharks are killed each year, yet they can only recover 4.9% per year.
The Leopard Shark (Triakis semifasciata) is one of the most common sharks along the west coast of North America.
All rays have their gills positioned on the underside of their head, where as the gills of sharks are positioned on the side of their head.
Wobbegong sharks have electroreceptors positioned on top of their heads for detecting fish passing over them.