How Well Do We Actually Know Sharks?

We have all seen blockbuster movies with sharks portrayed as the greatest sea monsters, thirsty for human blood. But what we see in movies is not so close to the truth. There is so much more when it comes to sharks than their eating habits. So, have you ever wondered how well we actually know sharks? 

Sharks are fascinating creatures that have been around for the last 400 million years (yes, they have coexisted with the dinosaurs and outlived them). Ever since they have diversified into more than 500 species. Media misrepresented them as rough sea creatures that could survive anything and it is often forgotten how vulnerable they are. In reality, sharks would much rather eat their natural prey than humans' flesh and they are the ones who are threatened by human activities. Due to Illegal and irresponsible fishing, their population has been reduced by over 70% in the last 50 years and they are now functionally extinct in some of the reefs. 

If you are amazed by sharks and would want to know more, keep reading! This article will answer some of the most common questions you might have about sharks and you will also read some interesting facts that may surprise you!


How many people are killed in shark attacks per year?

In the last ten years, the average number of people killed by sharks is less than five per year. The number of shark attacks is also decreasing. In 2019, there have been noted only 64 unprovoked shark attacks around the world.


How many sharks are killed by people each year?

Every year, people kill about 100 million sharks. Some sharks are killed in recreational fishing, but most of them are killed for their fins and meat. Shark fins have high monetary and cultural value and are used in some dishes such as shark fin soup (primarily in China and Vietnam). Even though shark meat is legal for consumption in the USA, dried shark meat has become increasingly popular in many other countries (Australia, Sri Lanka, Japan, Korea, India, and others). Shark meat is usually cut into steaks and fillets and prepared like meat from other large marine fish or is served fried with chips.


What shark species are the most endangered ones according to the International Union for Conservation of Nature (IUCN)?

According to the International Union for Conservation of Nature (IUCN), more than 5% of shark species are endangered (2.4% of them being critically endangered). More than 10% are listed as vulnerable, and over 14% as near threatened. Some of the shark species listed as critically endangered include the large sawfish, the common sawfish, oceanic whitetip shark, daggernose shark, and New Guinea river shark.


Do shark species attack each other?

Even though many shark species have specific diets, it is not uncommon for larger species, such as the great white sharks, tiger sharks, and mako sharks to eat smaller shark species in addition to fishes, seals, sea lions, and dolphins. The hammerhead sharks almost exclusively eat rays, which belong to the same family (Chondrichthyes or cartilaginous fish) as sharks.


What animals attack sharks?

Sharks are known to be at the top of the food chain, however, orcas (killer whales) are known to kill great white sharks. Sperm whales have been believed to attack sharks, as well. 




Do sharks live only in the ocean?

While sharks can be found in all oceans in the world, some of the species, such as bull sharks and river sharks, live in freshwater lakes and rivers. 


What is the lifespan of shark species?

Usually, sharks can live between 20 to 30 years when in the wild but there are some species that live longer (dusky shark can live 35 to 50 years, tiger shark 27 to 50 years, school shark more than 55 years, porbeagle between 30 and 65 years, and great white shark around 70 years). Spiny dogfish and whale sharks are estimated to have an amazing lifespan of up to 100 years while the oldest known shark in the world is the Greenland shark. In 2016, a group of scientists analyzed several female Greenland sharks and estimated that they are more than 250 years old, and may potentially be over 500 years old. Due to the fact that sharks shed their teeth many times during their lifespan, it is impossible to tell their age by observing and measuring the growth rings on their teeth. 


How many teeth do sharks have?

The exact number of teeth varies by species but sharks have several series of teeth in each jaw (up to 15). The largest and most powerful teeth are in front while the smaller ones and less functional are in the back. Unlike human teeth, shark teeth are not deeply rooted in the jaw so they can move and serve as replacements for the damaged or lost teeth up in the front. A shark can grow around 50,000 teeth in a lifetime. According to experts, there are trillions of shark teeth on the ocean floor.


Do sharks get cancer?

Yes, sharks can get cancer but some research shows that due to a compound called angiogenin, tumors' ability to grow is reduced.


Are sharks blind?

Even though many people are led to believe that sharks are either blind or have very poor eyesight, the truth is that they are able to see quite well. However, they are color blind.


How do the sharks hear?

Even though they do not have ears as humans do, sharks have very good hearing. They use a small opening that can be found on both sides of their head and lead to the inner ear.


Can sharks glow in the dark?

Yes, some shark species can glow in the dark. This phenomenon is called biofluorescence.


Is it true that whale sharks are bulletproof?

Yes, thanks to their six-inch-thick skin, whale sharks are practically bulletproof! Even though this is not the thickest skin when it comes to the animal world, it is thick enough to make it difficult for scientists to get a blood sample from a shark.


What are sharks' skeletons made of?

Sharks' skeletons are made of cartilage (the same material that makes our noses and ears), and their muscles are attached to their skin. Cartilage is not as dense as bones, making sharks lighter and more flexible.


How large can sharks be?

The longest shark (and the longest fish in the ocean) is the whale shark which can grow to be 60-plus feet long (around 20 meters). And when it comes to weight, the largest sharks are great white sharks. The largest great white shark that has ever been recorded is Deep Blue, which weighed 4,000 pounds (or 2 tons).


What shark species is the smallest one?

The smallest shark species is one of the species of dogfish sharks, called the dwarf lantern shark (Etmopterus perryi). It grows only up to 7.8 inches (or 20 centimeters). The dwarf lantern shark is also one of the shark species which emit light along its stomach.


Do sharks ever sleep or do they need to swim constantly?

Sharks do not sleep the same way as humans do but they do have active and restful periods. Even though some species must move constantly to keep water flowing over their gills (so that they do not suffocate), some shark species have spiracles that force oxygen-rich water through their gills allowing them to rest. Since sharks do not have eyelids, their eyes remain open even when they are resting and their pupils will monitor the nearby motions.


What date is the Shark Awareness day observed on?

The international Shark Awareness day is observed on July 14, every year. It is dedicated to debunking some popular myths about sharks, raising awareness of their endangerment, and learning people the importance of the role sharks have in the ecosystem.


What is cage diving?

If looking for more than just staring at sharks from behind the glass at an aquarium, you might want to try cage diving. You will dive inside a cage, allowing you to see a shark up close. It has been debated how this affects sharks and their eating habits, but cage diving has done some good, as well. As diving with sharks has gained more and more popularity, shark ambassadors started appearing around the world, trying to change the misrepresented picture most people have when it comes to sharks.


Hope this article has changed your view on sharks, as well! They are peaceful inhabitants of the ocean, most of the time just minding their own business and not threatening humans in any way. Instead, humans are the ones who should change their destructive and unsustainable fishing habits before it is too late and some of the shark species become extinct.


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