Shark Week
Whale sharks are the world's biggest fish, and they have big families, too! A whale shark was once found carrying 300 live shark pups.
Great white sharks eat 11 tonnes of food a year! Compare that to a human being: Each of us eats closer to half a tonne of food every year.
The spiny dogfish has the longest lifespan of all shark species studied, living to 100 years-old! On average, most sharks live to around 25 years-old.
Great white sharks are picky eaters. Their diet requires lots of fat, and after one bite a great white shark can determine whether or not the meal will satisfy its nutritional needs. If it doesn't, the shark will leave the rest and swim away.
Sharks can see in murky water because of a special feature that makes their eyes more sensitive to light. A membrane in the back of the eye called the tapetum lucidum reflects sunlight back into the eye, so the shark can make more use of what little light is there.
If the whale shark is the largest species, then pygmy sharks are among the tiniest! They measure an average of 8 inches (20 centimetres) in length and the can make their own light, a phenomenon that's especially helpful as pygmy sharks will dive more than a mile underwater to hunt.
You can't see a shark's ears, but that doesn't stop it from being able to hear you from more than two hundred metres away. That's because sharks only have inner ears, which they use to track the sound of their prey from lengths of more than 244 metres.
Angel sharks, also known as sand devils, will dig themselves into piles of sand. They lie in wait, waiting for unsuspecting fish to pass by before rising up and attacking.
Sharks' eyes are on the sides of their heads, so they have an amazingly wide sightline spanning nearly 360 degrees. Their panoramic view of the undersea world is inhibited only by two blind spots, one in front of the snout and the other directly behind the head.
Sound waves travel fast and far in water, so sharks have no trouble picking up low-pitched noises from movements such as fish schools, swimmers and even helicopters flying low over the ocean.
Blue sharks are among the most threatened species of sharks in the world. Trade in shark fins and overfishing have caused them to decline so rapidly that scientists worry about their future recovery.
Whale sharks are the world's biggest fish — and they have big families, too. A whale shark was once found carrying 300 live shark pups at the same time.
Sharks may seem like a permanent part of the ocean, but according to the World Conservation Union, 20 percent of sharks are close to extinction. The main culprit? Commercial fisheries accidentally catching sharks on their hooks and nets.
Some shark species will drown if they stop moving. Great white, mako and salmon sharks don't have the muscles needed to pump water through their mouth and over their gills. As long as they keep swimming, water keeps moving over their gills, keeping them alive.
Humans are the shark's biggest predator, but killer whales, crocodiles and seals have been known to eat sharks as well. Large sharks will even go after smaller, younger sharks that might make easy prey.
Sharks' skeletons are made entirely of cartilage, an elastic tissue that is much softer than bones. When a shark dies, salt from the ocean water completely dissolves its skeleton, leaving only the shark's teeth behind.
