Sharks are an ancient fish species, and from the many fragments of shark teeth and spines unearthed, their fossils appear even earlier than dinosaurs3.5-4.1Billions of years. In this long river of history, sharks have undergone natural selection, causing some species to disappear and become extinct, while those that survive now300There are still some vulnerabilities in various species, such as slow growth, delayed sexual maturity, and reproduction every two years1Moreover, the reproduction rate is extremely low. Do you like the shark wall hanging?