The first thing everyone should know about sharks is the most basic and primarily the most important; sharks are chondrichthyes, meaning their skeletal system is made up almost entirely of cartilage; not bone, like most fish. They share this characteristic with rays, skates, and a few crabs, snails, and cephalopods. This is very important information in relation to the sharks’ ecology in this planet’s oceans. Physically speaking, today’s modern sharks bear striking resemblance to the evolutionary ancestors; and the majority of sharks can be recognized as a shark by most people on this planet, although which order or subspecies they belong to, may escape most. Sharks have pectoral fins, unlike most fish, not attached to their head; and the dorsal fin is the most recognizable thanks to popular culture and many science fiction and psychological horror films. Size, and the number of gill slits depends on each species of shark. They may range in various sizes, and the largest fish in the ocean is a shark (the Whale Shark can reach as long 11-12 meters or 39 ft long). That may be a point of confusion for some; no worries though, actual whales themselves are not fish, but rather mammals, a fact that I am increasingly finding is missing from some education systems around the world.
Sharks breed and migrate differently depending upon the species. They can be found all over the planet’s oceans, and at varying depths. Taxonomist placements holds sharks in eight orders; with some 400 plus species. While I will not go into great detail regarding each individual order and class of species; it is important to note that many recognizable sharks are apart of a larger family, genus, and order of the taxonomic system, and while many generalizations may be made about one particular shark species, the same can not be done with the entire super order itself as it is as massive as it is diverse.
Beyond the cartilage skeletons, sharks are almost exclusively carnivorous (a few species actually eat plankton). And while prey, and hunting methods may differ between the species, the reputation these animals hold as hunters has not changed. Most recognizable sharks like the Great White, Hammerhead, and Bull; are at the top of their respective food-chains. Many myths and claims about shark cartilage and the shark themselves have proven unfounded, for example; shark cartilage prevents cancer, or sharks are immune to disease; although their bodies are designed to be less susceptible to disease, they are not immune to diseases. The origin of the word sharks comes from a variety of words used in ancient culture and language, with a mixture of European influence in the Caribbean in the 16th and 17th centuries and the ancient Mayan and Aztec languages. The word shark began to first see use in the very late 16th Century…