7 Surprising Facts About Sharks
Sharks have roamed the oceans for over 400 million years. Due to their size, strength, and impressive jaws, these evolutionary marvels have earned a reputation as dangerous predators.
However, there is much more to learn about sharks, an essential species in our marine ecosystems that need our protection!
To give you a brief insight into these incredible creatures, here are seven surprising facts about sharks:
1. There are Over 400 Different Species of Sharks Worldwide
Thanks to classics like Spielberg's "Jaws" and media coverage, the image that comes to mind when we think of sharks is usually that of the great white shark. However, there are hundreds of other shark species on the planet, ranging from the tiny 20-centimeter dwarf lantern shark to the 12-meter whale shark.
The waters off the Canadian coast alone are home to 28 species of sharks, including the Greenland shark in the Arctic and the spiny dogfish.
2. They Lose Tens of Thousands of Teeth
Shark teeth are constantly falling out and being replaced. They can lose up to 30,000 teeth over their lifetime. Fortunately, they have multiple rows of teeth, with the number varying by species. Each time a shark loses a tooth, the tooth in the row below moves up to take its place.
This is possible because shark teeth don't grow in their jaws but rather in the flesh covering them.
3. Shark Teeth Have Built-in Toothpaste
You might think that after biting into all those seals and fish, shark teeth would be full of cavities. However, scientists have discovered that sharks likely have the healthiest teeth in the animal kingdom. Not only do they regularly lose their teeth, but the outer coating contains fluoride, an active ingredient in most toothpastes and mouthwashes.
4. Female Sharks Have Skin Up to Twice as Thick as Males
Covered with millions of tiny modified teeth called dermal denticles, shark skin is incredibly tough, especially in females. Some females have skin up to twice as thick as their male counterparts.
This minimizes the damage that can occur during mating, when the male must bite the female's back, sides, and fins to position himself correctly. These bites are less intense than those made for feeding, but they can still cause injury.
5. They Have a Sixth Sense
Sharks are known for having highly developed hearing, smell, and vision, but some species also have a sixth sense called electroreception.
This network of gel-filled pores on their heads allows them to detect the electric fields of other living organisms, such as the heartbeat of hidden or camouflaged fish. This is why some sharks rely on their electroreceptors to locate their prey.
6. Some Females Can Reproduce Independently
Some female sharks can give birth without the help of a male. This natural form of asexual reproduction, where the growth and development of the embryo occur without fertilization, is called parthenogenesis, from the Greek words parthenos (virgin) and genesis (creation).
This usually happens when the genome of the egg duplicates to generate an embryo with the correct number of chromosomes and occurs in several shark species.
7. They Are Relatively Harmless
Although humans kill up to 100 million sharks annually, few shark attacks on humans are fatal, and researchers believe that most shark attacks are cases of mistaken identity.
Sharks may confuse struggling human arms or dangling feet with their prey, but when they bite and realize it's not a seal or a fish, they often swim away. The resulting bites are generally not like those Hollywood has depicted! A human is more likely to be struck by lightning than attacked by a shark.