Understanding sharks




DANGEROUS SHARKS
BULL SHARK

    The bull shark looks similar to the Great White, with a white belly and a grey back.  The bull shark has tiny eyes and long dorsal fins.  The bull shark has rows of teeth that are replaced when a row of teeth is broken lost, or, or worn down.  Bull sharks are usually seven to eleven feet long and can weigh between two-hundred-five-hundred pounds.
    A bull shark will eat mostly anything.  They are one of the most aggressive types of sharks and do attack humans since they swim in shallow water.  They also like to swim close to shore and around lakes, estuaries, and rivers.  The bull shark can also withstand fresh water for a short length of time.

TIGER SHARK

    The tiger shark has tiger-like markings on their back and a white belly.  They have large bodies and a blunt snout.  They also have a gill slit behind their eyes to all oxygen to flow directly to the brain.  They have a keen sense of smell and electroreceptors that are sensitive to electric currents in the water.  These sharks also have exceptional eyesight.  Tiger sharks have serrated teeth that are razor sharp and curved.  These creatures eat anything they can find alive. They feed on turtles, crabs, sea birds, reptiles, other sharks, mammals-ok, you get the idea, these sharks are serious hunters. Tiger sharks live in tropical climates, and swim both close to shore and out in the open sea.

GREAT WHITE

    The great white, the one most people know about and fear the most.  The white shark is a ferocious predator has can have up to 3,000 teeth.  They grow twelve to sixteen feet long.  The longest recorded great white was twenty-three feet long.  Females are larger than males, and the pups can over five feet long when born.
    Young white sharks eat fish, rays, and other sharks.  Adults eat seals, whales, otters, and sea turtles.  They also eat dead animals floating on the sea.  Whites do not chew their food, they swallow things whole.  The big meal can keep a shark full for up to two months!  These sharks use their sense of smell and sense of electric charges.  They can smell just a drop of blood in twenty-five gallons of water.  Also, the white shark breathes through it’s gills, not the nose.
    Sharks have a series of jelly-filled canals in the head called the ampullae of Lorenzini, and they use this to sense electrical discharges.  This also allows the shark to sense tiny electrical fields generated by animals.  Sharks also have magnetic fields for navigation.
    These sharks can be found all over the world, along the coastlines of the United States, including Hawaii, South America. Australia and New Zealand, and the Mediterranean Sea, among other places.