Sharks

The word ‘Shark’ invariably sends a shiver down our spine, our eyes widen suitably and we look duly impressed. It is a popular human belief that the shark hunts men down. The movie ‘Jaws’ went a long way in promoting this notion. Did you know that about 80% of the shark species have never attacked humans? Sharks are found in all the oceans of the world, but there are only four species that are considered dangerous: the great white shark , tiger shark, bull shark and oceanic whitetip shark. Humans are not the preferred food of sharks despite public hysteria and opinion to the contrary.

  • Description: A shark is a fish, and like other fish, it has a backbone, lives in water, and breathes through gills. Unlike other fish, a shark has a skeleton made of cartilage, the same material that makes up the end of your nose. Worldwide, there are over 350 species of sharks and 400 species of rays. Despite this diversity, you know when you're looking at a shark or a ray because their distinct body forms. Some adaptations enable sharks and rays to specialize in new ways of getting around, hunting, and feeding. These kinds of changes can increase the odds of survival, reproduction, and passing on those traits to the next generation, as well as enable species to use resources within a habitat differently, reducing competition.Most sharks are ectothermic (cold-blooded). Their inner body temperature matches the temperature of the water.
  • Food: A shark eats about 2 percent of its body weight per day -- slightly less than a human eats. Some sharks can live for a year without eating, surviving on the oil stored in their livers. The largest shark is the whale shark. At over 45 feet, it's also the world's largest fish. The whale shark strains out tiny animals that drift in the sea, such as plankton, shrimp, and small fish. Sharks are highly-specialized predators, with sharp teeth, strong jaws, streamlined bodies, and powerful senses. However, sharks don't hunt humans -- their feeding strategies evolved well before humans entered the water. Even today, of the over 350 different shark species, fewer than ten are considered dangerous to humans.There are almost six billion people on our planet, and less than ten people are killed by sharks each year. More sharks are killed by people -- over 12 million each year.
  • Other Facts: The smallest shark is the spined pygmy shark. It's less than 10 inches long and can be found in the cold, deep oceans. It's bioluminescent which means it glows in the dark.Most sharks are efficient swimmers. Sharks and shark by-products are important resources. Shark meat is high in protein, low in fat, and has no bones. One by-product, shark oil, is rich in vitamin A and is used in medicines, soap, cosmetics, and vitamins. Most sharks have 5 to 15 rows of teeth in each jaw. Unlike human teeth, shark teeth don't have roots to hold them in place, so their teeth are easily broken off. A tooth usually lasts about a week before it falls out. When this happens, the tooth behind it moves up to replace it. A new tooth can be replaced in as little as 24 hours.