The earliest sharks date from more than 420 million years ago, before the time of the dinosaurs! The 400 species of modern sharks have evolved in various ways and scientists have classified them into the 8 major groups shown in this graphic. See how sharks fit into this family tree, from the most well-known sharks like the great white and tiger sharks, to the bizarre lesser-known sharks like the frilled shark, goblin shark and cookiecutter shark.
Most sharks are content to be bottom dwellers. They scavenge the bottom for food at a slow methodical pace. A few predatory sharks have stronger tails that thrust them forward at great speeds to catch their prey. Periodically these sharks breach the surface in a burst of speed.
A writer from National Geographic describes what it’s like to see a flying shark:
The highest I have ever seen a white shark jump out of the water is about eight to ten feet [two and a half to three meters] clear of the water. Occasionally you will be looking vacantly out across the ocean and one of the sharks of Seal Island will suddenly take to the air, leaving you and your guests speechless as to how such a huge animal can jump so high.
We have on many occasions also seen makos go a lot higher than white sharks, and it is an amazing sight to see a cartwheeling mako in action. Many other species of sharks jump on a regular basis, such as threshers, copper sharks, spinner sharks, and salmon sharks. A breach usually lasts less than one second, so if you are looking in the wrong place, all you get to see is a big splash and a lot of hollering from those who did see it.
Part of the reason the Discovery channel runs shark week every year is that sharks are largely misunderstood creatures. True, they’re also scary looking efficient killing machines, but they are not as deadly as you might think. Only 15% of attacks result in fatalities and they are only the 10th most dangerous animal (as far as fatalities per year) in the U.S. So which sharks are the most dangerous? Check it out in this third infographic in our shark week series.
It may surprise you just how massive some sharks are. The largest shark, the whale shark is 2 feet longer than a typical school bus and weighs more than twice as much! (The average 38′ 84 passenger school bus weighs between 22,000-28,000 lbs). Luckily for us and most of the sea creatures out there, the two largest sharks alive today feed mostly on plankton. That makes the Great White the largest predator shark. On the other end of the scale the Dwarf Lanternshark is currently the smallest known shark, reaching only 8.3 inches (21.2cm) in length.
Yesterday marked the beginning of the Discovery Channel’s 25th season of Shark Week, an all out learning and entertainment fest centered on one of the least understood and most highly feared animals on our planet – the shark.
Here at Zoology Degree Online we love learning about all animals, but sharks are particularly fascinating.