Sharks

Sharks, a group of marine cross-mouthed fishes (Selachoidea), with spindle-shaped bodies, strong tails, mouth openings on the underside of the head, and 5-7 gill slits; mostly viviparous; egg-laying species have large eggs covered with a hard shell. Sharks sometimes enter rivers (Tigris, Ganges). Some species are used for food; in China, the fins are used to make a white glue used in cooking. Fat is boiled from the liver and used for food. The skin is used for various products. Some species of sharks reach 8 meters (Carcharodon Rondeletti) and are dangerous predators that sometimes attack humans. Sharks serve as subjects for anatomical and embryological research. Insulin can be easily extracted from the pancreas. Some sharks are poisonous, as they have a collection of epithelial follicles of glandular nature on the posterior surface of the spine of the dorsal fin (Evans). With this organ, sharks (Acanthias, Cestration) can inflict injuries that cause severe pain and swelling. The wounds persist for several days, and scars may form after healing. There are indications of the poisonous nature of various sharks when consumed as food. Symptoms of poisoning from meat or liver of Carcharius sharks appear half an hour to an hour after eating (vomiting, colic, headache, trismus, burning in the nose and throat, itching, weak pulse, accelerated breathing, prostration, dilated pupils, coma). Fatal poisonings have been recorded. The reason for the poisonous nature of shark meat has not yet been fully clarified. Shark meat is not tasty. Some people have an idiosyncrasy to it.