Not all sharks are so vicious!

Key Points

★ Even great white sharks don’t like to eat people, let alone the gentle whale sharks and basking sharks.

★ Don’t be fooled by the big mouths of whale sharks and basking sharks. They are filter feeders and are the largest fish in the world.

★ There are many species of sharks, and only a part of them are ferocious. Do not treat docile shark species as a source of shark fins that you can take at will.

When it comes to the most ferocious animal in the ocean, the first thing that comes to mind is the great white shark. Perhaps most people's understanding of sharks comes from the famous thriller movie "Jaws" based on the novel of the same name.

It set off a wave of shark-themed horror movies, including "Two-Headed Shark", "Three-Headed Shark", "Five-Headed Shark" and even "Six-Headed Shark". These whimsical shark fantasies fully demonstrated people's fear of this creature.

Sharks that can live in harmony with marine animals do exist. | Source: Internet

However, there are approximately a hundred cases of shark attacks on humans every year around the world, with only a few resulting in death. Among them are some gentle "little lambs".

01

Sharks don't actually like to eat people

It has to be admitted that the great white shark is the largest predatory fish known in the world. An adult great white shark can reach 5 meters in length and weigh more than 2 tons. It has several layers of sharp teeth in its big mouth. The edges of these teeth have a serrated structure, which is very suitable for cutting flesh and making people unforgettable... It also has a common name, called "man-eating shark".

In reality, great white sharks don't like to eat human flesh. | GIPHY

However, of the more than 530 shark species in the world, only a dozen have been confirmed to have injured people. Even the great white shark, which is famous for eating people, does not like to eat people because they prefer marine mammals with thick subcutaneous fat, such as seals, sea lions, whales and dolphins, or large fish such as tuna and swordfish. Human flesh may be "too dry" for them. Biologists have also found that the first reaction of many sharks after biting people is to spit out the human flesh.

Not only that, there are some sharks in the world that are much larger than the great white shark but are harmless to humans and animals. Whale sharks and basking sharks are among them.

Whale sharks and basking sharks are the largest and second largest fish in the world, respectively. They can be said to be the "leaders" in terms of size among marine fish. An adult whale shark is about 10 meters long and can weigh more than 10 tons. The largest whale shark discovered so far is 12.65 meters long and weighs 21.5 tons; an adult basking shark can be up to 8 meters long and weigh 9 tons. The largest basking shark is 12.27 meters long and weighs nearly 20 tons.

Whale sharks and basking sharks are very different in appearance, and even children can tell them apart at a glance.

The whale shark's spots are like stars in the sea, so it is called the "star shark". | GIPHY

The whale shark's mouth is wide and flat, with a width of up to 1.5 meters. Its back is grayish white and its belly is white. There are chessboard-like horizontal stripes on the surface of its body, and countless white spots, just like stars in the night sky. Fishermen have given this big guy the nickname "star shark".

The basking shark is not as bright as the whale shark, and often opens its huge mouth. | GIPHY

The mouth of the basking shark is also very large, about one meter wide, with a long and pointed "nose" in front of the mouth, which makes it look more "shark-like" than the whale shark. However, the body color of the basking shark is relatively monotonous, and it is not as bright and beautiful as the whale shark.

Don’t be scared by their wide-open mouths, they are actually “sheep in the sea”

02

I'm big, but I'm gentle

Whale sharks and basking sharks are large and look very brave, but their personalities are completely opposite to the fierce image of sharks in our impression. They are not "shark-like" at all and are very gentle. If the great white shark is the "jackal in the ocean", then it is not an exaggeration to call the whale shark and basking shark the "sheep in the ocean".

Whale sharks and basking sharks are both large filter-feeding sharks, so they will not attack humans, but there is still a difference in what they eat. Whale sharks mainly feed on algae, krill, small fish or eggs of other creatures, while basking sharks prefer small plankton, such as copepods or crustacean larvae.

Don't be afraid, the basking shark has only gill rakers in its mouth, no fangs. | GIPHY

There is also a big difference in the way they filter food. When the basking shark eats, it does not inhale seawater, but swims slowly in the sea with its mouth wide open, relying solely on swimming to make the seawater flow through its gills. Its gills are densely lined with black comb-like cartilage strips, called gill rakers, which have the function of filtering and retaining food on them. It takes about 1 minute to swallow a mouthful of food.

A whale shark pumping. Look closely, it doesn't have teeth either. | GIPHY

Whale sharks use a pumping method to feed: they take a big gulp of water and food, then close their mouths and open their gills to expel the seawater, and use their gill rakers to keep the food and swallow it into their stomachs. Of course, whale sharks sometimes also use passive filtering to feed by swimming with their mouths open.

Why are these filter-feeding animals so large yet so gentle?

This is because their huge size can protect them from attacks by predators and store more energy. After a big meal, they have enough energy to migrate for a long time without eating. Small foods such as plankton are abundant in the ocean, so they don't need to compete with other animals for them. Therefore, the teeth, claws and other organs used for hunting of filter-feeding animals tend to degenerate. Over time, they become more and more Buddhist and become big, good-tempered guys.

03

Evolution makes sharks gentle

But why are there gentle filter feeders among the supposedly ferocious sharks?

In fact, "all sharks are ferocious predators" is just a stereotype of ours. A group of organisms will try to occupy more ecological niches so that they can have better adaptability and allow their population to continue. The purpose of life is to allow its genes to continue, and when a way of survival becomes profitable, organisms will gradually adapt to this way of survival during the evolution process.

For example, the ancestors of giant pandas lived in an environment with a lot of bamboo, and few animals eat bamboo. Eating bamboo means that there are almost no competitors to compete with them for food. At first, they may have only eaten part of the bamboo to fill their stomachs, but as they evolved, they gradually became the giant pandas we see today that feed entirely on bamboo.

In fact, the ecological diversity of sharks far exceeds our imagination. In addition to species like the great white shark that swims quickly on the surface of the sea and actively hunts, there are also species that lie on the sand on the seabed and wait for prey, species with lumpy teeth that specialize in chewing crustaceans, and even species that are dozens of centimeters long but specialize in biting off a piece of meat from large fish or even whales.

Shrimp sharks like to lie on the seafloor and wait for food to come to them. | Source: Internet

Therefore, although they are all sharks, different species and different feeding habits have very different shapes and structures, and this is also true for filter-feeding sharks. Their ancestors may have also preyed on other fishes, but later due to environmental changes, there were a large number of small and medium-sized creatures in the waters where they lived, and they gradually adapted to the filter-feeding feeding method, becoming today's whale sharks and basking sharks.

There are many marine creatures that live by filter feeding. Small ones include sardines and herrings, and some are giants in the ocean, such as manta rays, megamouth sharks, and various baleen whales. There are also many large filter feeders in ancient marine life, such as the Cambrian Triton, the Jurassic Lizard, and the Cretaceous Miraca hawk shark.

Manta rays, also known as devil fish, are also gentle filter feeders. | GIPHY

Once large filter-feeding fish such as whale sharks, basking sharks, and manta rays grow up, they have almost no natural enemies in nature. However, due to the uncontrolled overfishing and hunting by humans, their wild populations have declined rapidly. If they are not protected, they may soon disappear from the earth. Although the economic activities of killing sharks are now completely banned, the phenomenon of killing protected sharks still exists. There is no killing without buying and selling. These gentle big fish have only appeared on the earth after millions of years of evolution. Don't take advantage of their gentleness to satisfy our appetite.

Author | Li Weiyang, a popular science writer, has published works on Guokr.com, State Forestry Administration, China National Geographic, "Bowu" magazine, Juvenile Science Magazine, etc.

Review | Huang Chengming, Researcher, Institute of Zoology, Chinese Academy of Sciences

Editor | Jiang Fan

Editor | Zhou Ziqing

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