Sharks are astonishing creatures. They can grow as long as the semis you see on the interstate, in the case of the whale shark, or they can be only as long as your mobile device, in the case of the dwarf lantern shark. They can be as terrifying as the great white shark or as docile and harmless as the basking shark.
Here are 10 fun facts about sharks that will give you a new appreciation for this ancient beast that has swam the world’s oceans for 420 million years and miraculously survived all five of the earth’s major mass extinctions.
1. A shark may grow (and lose) over 30,000 teeth in its lifetime
Sharks have shockingly sharp teeth, situated in rows in both the upper and lower jaw. When a shark loses a tooth, the one directly behind it moves forward to replace it, much like a conveyor belt. At any given time, a great white shark has about 70 teeth in its mouth, divided among around five rows, while a bull shark may have as many as 300 teeth distributed among about 50 rows!
2. The whale shark has about 3,000 tiny teeth at one time, but doesn’t use any of them.
That’s because whale sharks are filter feeders. As the whale shark swims through water with its mouth open, a built-in filter, commonly known as a “gill raker,” traps teeny tiny and microscopic plankton, which is their main form of nourishment. It’s interesting that the largest fish in the sea eats the smallest creatures in the sea.
3. The goblin shark has an extendable jaw.
That’s right! The goblin shark’s snout is long and flat, resembling a sword, and beneath it are its formidable jaws that protrude about one-third of the way along the length of the snout. But when prey is nearby, this shark can extend its jaws all the way to the end of its snout, grab the unlucky dinner, and then retract its jaws.
4. Sharks have two sensory organs that humans don’t have.
We tend to think that our five senses are the only senses, but we’re wrong! In addition to the senses of sight, sound, taste, smell, and touch, sharks have two sensory organs that we don’t.
The ampullae of Lorenzini is located on the shark’s snout and can detect electrical impulses given off by living things.
The lateral line extends along the sides of the shark from head to tail and can sense even minute vibrations in the water that signal nearby prey.
5. Sharks give birth in three different ways.
Oviparous sharks include bamboo and bullhead sharks, and they lay eggs that are crowded into a protective sac known as a “mermaid’s purse.” The sac attaches itself to a rock or other underwater surface for protection until the shark pups hatch.
Viviparous sharks include blue and hammerhead sharks, which grow live sharks in their bellies, which are nourished with a type of placenta, and give birth to fully developed shark pups.
Ovoviviparous sharks include whale and tiger sharks, and they keep their eggs inside instead of laying them. The eggs hatch while still inside the mother, who then gives birth to live sharks.
And believe it or not, some female sharks can have pups without the help of a male shark. This is called “parthenogenesis.”
6. You’re more likely to be injured by a toilet seat than by a shark.
The United States averages about 19 shark attacks a year, with one fatality every two years. In 1996, 43,000 Americans were injured by a toilet seat.
In the year 2000, a typical year for shark attacks, the estimated attendance at U.S beaches was 264,156,728. There were 132 drowning fatalities that year, but of the 23 shark attacks that occurred, there were no fatalities.
7. But you won’t believe how many sharks are killed by humans every year.
It used to be believed that humans killed about 73 million sharks each year. However, a recent scientific study published in the journal Marine Policy reveals that this number is closer to 100 million, which means that 190 sharks are killed every minute of every day. And even more horrifying is that the study suggested that 100 million is a low estimate, and the real number may be as high as 273 million, or 519 sharks every minute. No wonder over 100 species of sharks are on the IUCN’s Red List of Threatened Species!
Sharks are hunted for sport, for the oils in their liver that are used for cosmetics and other products, for their skin, which is used to make fashion accessories, and for their fins, which are the featured ingredient in shark fin soup, a delicacy in some Asian countries. Those not killed directly by the hands of humans end up trapped in fishing nets or on longlines.
8. Two-thirds of a shark’s brain is dedicated to its sense of smell.
Many sharks can detect a single drop of blood in 25 gallons of water, which is impressive, but others can detect one drop in an Olympic-sized swimming pool! But it’s not just blood they smell. The lemon shark can sniff out a few drops of tuna oil in an average-sized home swimming pool.
9. Sharks band together in schools much of the time, but they usually hunt and eat alone.
If a bunch of sharks happen to smell another shark enjoying a bite to eat, they may come to the scene to see if they can get in on the action. A feeding frenzy may ensue, with sharks biting and getting bitten by one another in the chaos.
The notable exception is the great white shark. These polite animals won’t fight over food. If one great white doesn’t feel like sharing, the sharks will have a tail-slapping contest to decide who gets to eat.
10. Some sharks live in the “permanent midnight zone.”
Most sharks live relatively close to the surface of the ocean, but some, like the goblin shark, live in the “permanent midnight zone.” The goblin shark has been known to live as far down as 4,700 feet, but scientists say that the deepest confirmed report of a shark is 2.29 miles, or a staggering 12,139 feet!