Classification of sharks
Sharks are classified as one of the types of cartilaginous fish, and it is specifically one of the two types of famous cartilaginous fish, as cartilaginous fish are classified into two main groups, namely as follows:
Whole heads: (Holocaust).
Lamellar cartilaginous gills (Elasmobranchii)
Sharks belong to this group, where there are 8 different ranks of sharks within it, and each rank indicates certain physical, biological, and behavioral characteristics of the shark in it.
Sharks can be classified scientifically in detail, for example, the short-finned mako shark can be classified as follows:
The animal kingdom.
Leucorrhoea, mackerel shark.
Anatomy of a shark :
The internal parts of the shark consist of elastic cartilage instead of bones, Sharks have a cartilaginous structure, they have 5 to 7-gill slits on each side of their head, as these gills are used for breathing purposes and extracting oxygen from the water.
They also have mouths lined with multiple rows of teeth that change and renew periodically, and their teeth shapes and sizes vary, as there are some that are sharp and sharp, and there are some that are pointed like spears.
There is a lateral line on each side of the shark’s body, and the function of these lines is to detect the movement of the surrounding water in it to sense the movement of prey and help in moving around these prey, especially at night when underwater visibility is poor
These lines are sensor systems consisting of a network of fluid-filled channels under the shark’s skin, where these channels are affected by pressure changes in the water surrounding the shark and lead to vibration of the liquid contained in these channels, and this vibration is transmitted to the nerve endings of the shark, and then the signal is transmitted to the brain to be able to determine the appropriate direction of its movement.
Shark sizes :
The sizes of sharks differ from each other, the largest species is the whale shark, which can reach a length of 16.7 meters, and is the largest fish on Earth in general, and the smallest species is the dwarf lantern shark, which does not exceed the length of 20 cm, that is, it is the size of a handcuff, and there are other species of medium size such as the Great White Shark.
Native shark :
The habitats of sharks vary according to their species and each species adapts to the surrounding environment, as sharks are considered well adaptable to their surrounding environment, and the different types of sharks are distributed between shallow coastal areas, deep ocean bottoms, and in the open ocean.
Some species of sharks live in temperate tropical seas, some of which live in cold and polar seas, others live in freshwater, and some species of sharks and the environment in which they live:
Sleeping Sharks :
It lives in Arctic waters throughout the year.
Big-eyed dog Sharks :
It lives at the bottom of the Red Sea at an estimated depth of about 2,195 meters.
Bull sharks :
It is often found in fresh waters, such as the waters of Lake Nicaragua, Lake Izabal in Guatemala, the Zambezi River in Africa, the Tigris River in Iraq, and 255 km from the top of the Atchafalaya River in Louisiana, and it is known that this species of sharks traveled an estimated distance of 1,609 km up the Mississippi River to Illinois until dams closed their way.
The shark’s diet :
Sharks rely on hunting for their food because they are predatory and ferocious creatures that feed on a variety of marine animals, which allows them to move freely and repeatedly around the ocean without fear of interruptions in food sources.
1 shark usually feeds on fish and marine mammals; such as dolphins, seals, and some smaller sharks, and there are species of sharks that prefer turtles, gulls, crustaceans, marine mollusks, and plankton as their diet.
Shark behavior :
Most sharks need to provide constant movement of water around their gills, which provides them with the necessary oxygen, and for this, they need to be in constant swimming movement, even during periods of sleep, as they swim during sleep in the water, but their brains are less active.
But there are other types of sharks that do not need to swim continuously in the water because their bodies have small ventilation holes located directly behind their eyes and these holes push water through the gills to complete the breathing process.
Shark mating :
The process of reproduction of sharks is similar to the process of reproduction of mammals, where adult male and female sharks must meet physically so that the male can pass his male gametes to the female’s body and fertilize her eggs, and this process differs from the method of reproduction of other fish species, where ordinary fish reproduce by releasing their gametes to meet with eggs and fertilize them.
Shark sleep :
Most shark species are unable to sleep for long periods and compensate for it by taking breaks to renew their activity, by sleeping for very few minutes at a time, and the reason why sharks are unable to sleep is that they need to swim constantly so that they can breathe, as water saturated with oxygen flows through their gills when they move.
But some species of sharks can sleep thanks to having gills capable of pushing oxygen-rich water into them without the need to swim and move water through them, an example of which is the nurse shark
Types of sharks :
There are many types of sharks, numbering about 400 species, and the most famous of them are:
Whale shark :
It is the largest fish species in the world, reaching a length of about 20 M, and weighing about 34,019 kg, and this type of shark is characterized by its gray, blue, or brown skin, which is covered with regular light-colored spots, and the whale shark is abundant in the Pacific, Atlantic, and Indian oceans.
Basking shark :
It is the second largest fish species in the world, reaching a length of about 12 M, and weighing up to 7,000 kg, and it was named so because it often climbs to the surface of the ocean to sunbathe, and one of its famous behaviors is slow swimming forward while filtering the water that enters its mouth from prey.
Mako shark :
It is the fastest type of shark, and it is characterized by having short fins, and the length of the mako shark may reach almost 4 M, and its weight reaches 553 kg, and its belly appears lighter in color than its blue back, and this species is abundant in temperate and tropical waters in the Atlantic, Pacific, Indian, and Mediterranean oceans.
Thresher shark :
It is characterized by having large eyes, small mouths, and a long whip-like tail to collect prey and stun them, and there are 3 types of this shark, namely: common thresher, protruding Thresher, and sea thresher shark.
Bull shark :
It is one of the most aggressive types of shark on humans, as it prefers to be in warm, shallow, shaded waters, and near the shore, and is characterized by having a sharp nose, a gray back that becomes lighter at the bottom, and the length of this type of shark reaches about 3.5 m, while its weight reaches 226 kg.
Great white shark :
The length of the great white shark is about 6 M and weighs approximately 1,814 kg, and it is one of the ferocious scary sharks that may bite humans but not devour them, and one of the strange nature of the White Shark is that it examines its prey before devouring it.
Hammerhead shark :
The hammerhead shark is an oceanic fish that is characterized by having a strangely shaped head, which gives it a wider range of vision, and it also lives in tropical and temperate oceans, and the hammerhead shark includes several types: wing-headed, hammerhead, shell-hammerhead, Muscovite, large hammerhead, and two-headed sharks.
The relationship of sharks to humans :
Widespread misinformation about sharks as man-eating fish has led to an increase in attempts to eliminate and catch them, but the fact is that there are only 10 species of sharks that pose a real danger to humans.
The rest of the species do not pose any danger to humans unless they are threatened, so it is necessary to treat Sharks fairly, without aggression, and avoid provoking them or notifying them of the threat to avoid their reaction.