Sharks belong to the cartilaginous fish and are closely related to rays. There are over 350 species in total, which are found in both oceans and fresh water. Sharks range in distance from 30cm to 18m. Of the 250 species, only 10 are dangerous to humans.
General
Sharks have a very good sense of smell, they are able to smell a drop of blood divided into millions of water drops. The shark always uses its sense of smell to locate victims in the first place. After which he devours them. The shark also uses its sense of smell to detect enemies from a great distance.
Sharks generally have good eyesight contrary to what many people claim. The shark is one of the few animals that is highly developed in every way. The shark has 3 eyelids, 2 of which cannot close. When in danger, the third eyelid is used to protect the eyes during an attack. White sharks don’t have this, but roll their eyes back into their eye socket.
Most sharks reach an age of 20 to 30 years. Although there are some shark species such as the whale shark that can reach an age of more than 100 years. Few animals can do this, another well-known animal that can do this is the elephant, which is also known for easily reaching ages above 100 years.
Construction
The head of a shark is large and cone-shaped, the shark has small eyes on the side of its head, in the front are the nostrils, on top of the snout. A shark’s skin consists of serrated skin teeth. The skin is very strong. The shark often takes advantage of this in combat. Along the side of the jaw edge, there are a whole row of incisors to attack. These are usually razor sharp. The skin can be compared to an armor and can take a lot of impact. In the water the shark is a formidable opponent, usually not for humans, but for fish and other animals in the water.
The shark has 5 gill slits on the side of its head. This is used to extract the oxygen from the water. Many sharks have to keep swimming to have enough oxygen. But many species also open their mouths, so that oxygen can be better absorbed through the gills. This allows them to breathe when lying still.
A shark’s torso consists of internal organs. The pelvic fins, second dorsal fin and anal fin are located more on the back of the body. Furthermore, the shark has a dorsal fin and pectoral fins that aid in swimming. On the back of the shark you have a tail fin. It is usually large and very muscular. This ensures that the shark can move at very high speeds.
Endangered species
Sharks are an endangered species. Many sharks get caught in nets despite their sharp incisors. Sharks are declining in large numbers, especially in the Atlantic Ocean. Sharks also give very few offspring per individual, so the low shark population is very difficult to recover.
