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Sharks and Rays…<\/p>\n
\u2026 don\u2019t have any bones! Their entire skeleton is composed of cartilage. That\u2019s why they are called cartilaginous fish<\/p>\n
\u2026 can fall into trance! If they\u2019re turned upside-down, sharks fall into a state of paralysis and become perfectly still<\/span><\/p>\n \u2026 are among the oldest fish! The first appeared over 450 million years. They\u2019re older than the dinosaurs!<\/p>\n \u2026 include the largest fish species in the world \u2014 the whale shark<\/p>\n <\/p>\n \u2026 don\u2019t live exclusively in seas and oceans! Some species, such as the bull shark or several ray species can live in rivers or lakes, temporarily or indefinitely.<\/p>\n \u2026 can be pregnant for up to two years!<\/span><\/p>\n \u2026 possess a sixth sense! Sharks and rays have special organs called the Ampullae of Lorenzini, which can detect electric vibrations. Animals possessing such organs can find prey by sensing its heartbeat<\/p>\n \u2026 attack humans far more rarely than many other animals! Cows, hippos, mosquitos and dogs are just few among many species that attack humans far more frequently than sharks<\/p>\n \u2026 include some species that don\u2019t ever sleep! Some species of sharks need to constantly keep swimming in order to breathe, and so can never sleep! They remain semi-conscious while they rest.<\/p>\n \u2026 can have up to 15 rows of teeth! The largest and strongest teeth are found in the first row<\/p>\n \u2026 can move both upper and lower jaw! In cartilaginous fish, the upper jaw is not attached to the skull, and can move independently of it<\/p>\n \u2026 don\u2019t have a lot of predators, but humans present the greatest threat to sharks and rays! Over 100 million of sharks are caught each year, and that\u2019s not including rays!<\/p>\n\n\n
\n \u2026 reproduce in different ways! Some species lay eggs, some carry eggs in their bodies until they hatch, and yet others give birth to live young, similar to mammals.<\/span><\/p>\n \n\n
\n \u2026 include some species whose embryos attack one another while still in the womb! This is called interuterine cannibalism, and only the strongest young survive, while the others are eaten.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \n\n
\n \u2026 do have scales! They are different from scales in other types of fish, and each consist of a tiny hook curved towards the animal’s tail. If you pass your hand over the shark’s body going from head to tail, it will feel very smooth, and very rough if you go in the opposite direction \u2013 from tail towards its head.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n