Sharks are often portrayed as scary creatures in American movies.
But are they really that scary?
If you get to know sharks very well, you might find that they are not that scary after all.
Let’s take a look at what kind of creature sharks are!

Ads

～ Basic information. ～

Animalia-Chordata-Chondrichthyes-Elasmobranchii-Heterodontiformes-Lamniformes-Pristiophoriformes etc.

As of 2020, 509 species of sharks have been identified in the world, belonging to 9 orders, 34 families, and 105 genera. In the waters near Japan, 130 species of sharks have been identified, belonging to 9 orders, 32 families, and 64 genera.

The size of sharks varies greatly depending on the species.

smallest shark:smalleye pygmy shark.
Maximum length:22㎝　weight unknown.

biggest shark:whale shark.
Maximum length:20ｍ　weight:20ｔ.

On average, there are many sharks of 1m to 3m.

Sharks are found in the vast oceans around the world.
Some sharks also live in brackish water, freshwater, and deep sea.

Ads

Shark’s Q&A.

Do sharks really attack people?

Many people may think of sharks as scary creatures due to their portrayal in movies and other media. While it is true that there are news reports of people being attacked and killed by sharks.

Only about 10% of all sharks, such as the great white shark, are known to attack humans.

Most sharks, such as the whale shark, feed on plankton and do not attack humans.

So while it is best to avoid sharks if you see them, not all sharks are scary.

Why don’t aquarium sharks attack other fish?

As you may have learned from the previous question, some sharks feed only on plankton and do not attack humans. However, it is true that some aquariums keep great white sharks, which are known to attack humans, in the same tank as other fish.

So why don’t sharks attack fish? The answer is simple: they are not hungry.

Sharks in aquariums are fed plenty of food by their caretakers, so they do not need to chase after fish.

Of course, if the caretaker forgets to feed them, they may start attacking other fish.

How do sharks sleep?

There is still much we do not know about shark sleep.

However, it seems that sharks are able to see their surroundings while sleeping, which is quite different from our own sleep.

They seem to be able to take a “nap” while resting only part of their brain. Do sharks dream? There is still much we do not know about shark sleep, but it will be exciting to learn more in the future.

Can you eat sharks?

Yes, we can eat shark meat.

One of the world’s three great delicacies, shark fin soup, is made from the dorsal fin of a shark.

You may think that shark fin soup is a luxury food that is not often eaten, but we actually eat shark meat quite often in our daily meals.

They are “Kamaboko” and “Hanpen”.

This is because when shark meat goes bad, it smells like ammonia and is not very tasty. Therefore, it is processed into fish paste products by grinding it up.

Check the ingredients on the back of kamaboko or hanpen and you may see “shark” listed.

Is it true that sturgeon is not a shark?

Yes, that’s true.
Sturgeon eggs are famous for being one of the world’s three great delicacies, caviar. Those black, gem-like eggs are quite different from shark eggs, which are larger and have a different shape.

Since their skeletal structures and evolutionary origins are different, sturgeon is not a type of shark.

It seems to be common knowledge among shark enthusiasts!

How long have sharks been around?

Since when have sharks been swimming in that ocean?

Shark fossils have been found since the Devonian period of the Paleozoic era. Shark fossils generally only contain teeth.

The reason why there are no bone fossils like those of dinosaurs is that shark bones are cartilaginous and decompose over time due to microorganisms.

Fossils from this period include the Megalodon, which was the subject of a movie a while back and is still rumored to be alive today!

How are sharks born?

There are species of sharks that are oviparous and viviparous.

Among them, some sharks are called ovoviviparous and hatch eggs inside the uterus. The baby sharks born inside the uterus feed on other baby sharks or eggs that are born later.

Carnivorous sharks engage in cannibalism even before they are born, so only one shark survives. It’s scary because it’s something that can’t happen in humans.

Is it true that sharks are sensitive to odors?

This is true. Sharks have poor eyesight and are therefore very sensitive to smell.

However, they are not sensitive to all smells, only to the smell of blood.

Depending on the species, they can detect the smell of blood diluted to one part per million.

I think it’s safe to say that beaches and other swimming areas are safe because shark nets and other deterrents are used, but it’s probably best not to go swimming in the ocean when you’re bleeding.

Is the ancient shark, Megalodon, still there?

This is the Megalodon, an ancient shark that is said to be extinct.

This is the Megalodon, an ancient shark that is said to be extinct. There are currently no known Megalodons, but there have been reports of bite marks on ships that are much larger than those of any known shark species and sightings of large fish shadows.

There have been some reports of sightings that suggest that we may see news of the discovery of a Megalodon in a few years!

Ads

Type of shark.

• Whale shark.
• Great white shark.
• Japanese bullhead shark.
• Thresher shark.
• Megamouth shark.
• Hammerhead shark.
• Bull shark.
• Frill shark.
• Japanese angelshark.
• Japanese sawshark.

Etc.

Bibliography.

フリー百科事典『ウィキペディア（Wikipedia）』　サメ
https://ja.wikipedia.org/wiki/サメ#分類

サメの不思議
http://oki-park.jp/userfiles/files/worksheet/shark_study_1610.pdf

フリー百科事典『ウィキペディア（Wikipedia）』　ツラナガコビトザメ
https://ja.wikipedia.org/wiki/ツラナガコビトザメ

水族館のサメが他の魚を食べない理由は…　小魚たちとの関係も明らかに
https://sirabee.com/2019/09/14/20162162990/

ジンベイザメって眠るの？サメと睡眠の秘密　こんにちは！ジンベイザメさん
https://jimbee.jp/archives/2191

サメの肉は食べれる？美味しい？アンモニア臭？　珍肉ナビ
https://chinniku.nav1.net/shark/

「チョウザメはサメじゃない」サメ好きの常識をマジで解説
https://shark-ricky.com/2018/06/12/sturgeon_is_not_shark/

アイキャッチ画像
https://pixabay.com/images/id-1294753/