The Shark, Not Man's Best Friend
Sharks are related to many species such as skates, rays, and sawfish, which are all included in the elasmobranch family. They have been part of the ocean's waters for more than 400 million years. There is a total of about 400 different species of sharks, but all have common characteristics. Sharks contain a skeleton made of cartilage. They use all five senses, just like humans, and also have the use of electrosensitivity, which helps them find hidden prey. Sharks do not contain a swim bladder or well-developed ribs, therefore, they are not buoyant. So, unless they continue to swim, they will sink slowly. Sharks are equiped with five to seven pairs of gills on the side of its head that allow water to pass through. The gills are the site of oxygen collection for most marine animals.
Sharks are animals that reproduce by internal fertiliztion. Most are flesh eaters, but some feed by filtering water for the collection of plankton and small fish. Shark teeth are parallel and continue to be replaced throughout the shark's life. The different shapes of a shark's teeth tell a lot about what it eats.
A Shark's Teeth |
Shark Teeth Size |
Specialization |
thin pointed |
grabbing and holding prey |
serrated, wedgeshaped |
cutting out big mouthfuls |
small conical |
crushing invertebrates |
Sharks have a horrible reputation, influenced by such movies such as JAWS. But the truth is that sharks seldom bite people. When, they do though, the bite can be very painful and many times serious because of the heavy bleeding and loss of skin. Studies that research the behaviors of sharks report that sharks attack for one of four reasons:
- Mistaken identity when a swimmer is among fish that a shark could be feeding on.
- When the shark believes that a human is an intruder.
- When a person bumps into or steps on a shark.
- Or when a person intentionally molests a shark.
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