Hundreds of millions of years old, sharks are the true apex predators of the ocean. Sharks inspire fear and fascination, but how well do you know them? Test your shark IQ with this HowStuffWorks quiz!
On average, in the US alone, sharks only kill one person every two years. You are more likely to die in a car crash, fall or by legal execution than you are to die in a shark attack.
Shark brains are uniquely specialized to make them expert hunters. 2/3 of their brain is dedicated to smell and they can even feel the electrical field coming off prey.
Sharks have been around in some form for roughly 400 million years. They are older than and have outlasted the dinosaurs.
There are over 400 types of shark, ranging from the very tiny to the very large. They are diverse creatures with different looks, habits, diets and temperaments.
There are over 400 types of sharks. Only 30 of these species are known to attack humans. Many are even quite shy.
Sharks are a type of fish. They belong to the class Chondrichthyes.
If a shark's tooth falls out, one will come forward from one of their many rows of backup teeth to replace it. Sharks can use as many as 20,000 teeth during their lifetime.
Many species of shark are very solitary creatures who prefer to hunt and eat alone. However, they can get involved in feeding frenzies over large kills where they end up taking bites even out of each other.
Almost all sharks are carnivores and some are known to eat other smaller or less aggressive species of shark. For example, a tiger shark might hunt and eat a bull shark.
While the scary "killer" sharks get all of the attention, some are actually gentle creatures that survive mostly by filtering plankton out of the ocean water as they swim. The basking shark and whale shark are harmless giants that eat in this way.
Giant great white sharks are the most infamous of sharks for a reason. They are responsible for more attacks on humans than any other shark.
Sharks skeletons are made entirely out of cartilage. This lightweight and flexible skeleton makes them swift hunters.
These large and hungry sharks are responsible for the second most human attacks after The Great White Shark. They tend to be very aggressive when they see humans in the water.
Shark meat itself has no particular effect on one's health at all. However, shark meat often contains mercury, which can poison you.
Makos are a popular choice for shark fin soup. Due to this, overfishing is threatening their population.
There are hundreds of species of sharks, and they give birth in a few ways. Mother sharks can birth between 1-100 babies at a time, depending on the kind of shark.
Some species of shark are thought to live longer than a century. These include the spiny dogfish shark and massive whale shark.
Depending on the species, shark mothers either leave their children as eggs to hatch or give birth to them live and swim away. Some even eat their own young if they don't swim away fast enough.
The "shark" used for the movie was a mechanical monstrosity. Steven Spielberg had endless trouble getting it to work.
This shark has a distinctive white-tipped fin and is known for getting into feeding frenzies as sailors wait in the water for rescue. It is an opportunistic and unpredictable killer.
Mako sharks can swim as fast as 20 miles per hour, making them the fastest of sharks. They swim in a unique figure 8 pattern before attacking prey.
Bull sharks are believed to have attacked more humans unprovoked than any other shark. They also can hunt in both fresh and saltwater.
In the ocean, 74 species of shark are listed as either threatened or critically endangered. Man is the biggest threat to the shark.
Finning alone kills an estimated 73 million sharks per year. In this practice sharks are caught alive, their fins are ripped off and they are thrown back into the sea until they bleed to death or drown. This is just one of the ways man kills sharks daily.
The Dwarf Lanternshark may just be the smallest shark on earth. These sharks can only be found deep in the water off of the continental slopes of Venezuela and Colombia and grow as large as roughly 8 inches.
Lifespan varies by shark species. However, if left alone, these apex predators generally live a lifespan of 20-30 years.
Many apex predators are used to having their prey run away and have no idea what to do when confronted. Many sharks will choose an to swim away and find an easier meal rather than fight with their prey.
While many people believe that sharks are mindless killing machines, this is not true. Sharks are curious creatures and one meal can fill a shark for several months at a time.
Most sharks bite humans out of curiosity or because they think we are seals or other natural prey. They then let go once they realize we are not seals because we do not taste good to them.
Cookie cutter sharks are some of the tinier sharks, at under two feet in length. They are known for cutting perfectly round chunks out of living dolphins and whales with their unusual jaws.
These large and distinctive predators are unlikely to attack people. Their preferred meal is the stingray.
This shark is one of the most dangerous to people because it is highly aggressive and can swim in both salt and fresh water. They have been found in rivers as far inland as Illinois and Ohio.
Tiger sharks are known for attacking people and have been found with all sorts of bizarre things in their stomachs. These include things like cushions and alarm clocks.
The whale shark is the biggest shark and fish. It is not a whale, as whales are mammals.
Zebra sharks are small gentle animals that do great in aquariums. Their tail is half of their length.