SWIMMING:

  1. Some sharks are fast swimming predators that live in the open ocean, like the mako. Some sharks are slow swimming bottom dwellers that eat shell fish, like the angelshark. Some sharks are slow swimming filter feeders that sieve tiny animals and plants to eat, like the whale and basking shark.
  2. Sharks cannot stop suddenly or swim backwards. The pectoral fins of a shark cannot bend upwards like a fish, limiting its swimming ability to forward motion only. If a shark needs to move backwards, it uses gravity to sink backwards, not swim backwards. Sharks can't simply stop in order to avoid swimming into something, they must swerve to the side in order not to hit an object in their path.
  3. Some sharks swim by propelling themselves through the water using their tails, like great white sharks. The fins are only used for balance. Other sharks, like the whale shark, move their bodies from side to side to propel themselves through the water.
  4. There are 6 different body forms that sharks use to swim. These body forms include cruisers, generalists, wrigglers, floaters, undulators and flappers.

The nurse shark shown swimming in this video shows an example of a wriggler body form...

SYMBIOTIC RELATIONSHIPS:

  1. Pilotfish often travel with sharks, for unclear reasons. This relationship may be due to the natural schooling behavior of pilotfish, or the pilotfish may conserve energy by riding the wake of the shark. Pilotfish also eat small amounts of food scraps that are released as a shark feeds.
  2. Several species of small fishes, like the cleaner wrasse and remora, are "cleaners" that pick debris or parasites from sharks.

DIET AND EATING HABITS:

  1. As a group, sharks and batoids eat almost anything: fishes, molluscs, marine mammals, and other sharks.
  2. While some sharks are not very picky eaters, certain sharks eat some foods more than others. In other words they have a favorite food. For example, hammerhead sharks eat primarily stingrays; bull sharks eat primarily other sharks; smooth dogfish eat primarily crabs and lobsters; and tiger sharks eat primarily sea turtles.
  3. Many sharks prey most often on the weak, inferior members of a population. They select weak, ill, injured or dying prey because it is easier to catch.
  4. There are a couple of things a shark can't eat. Sharks cannot eat the Moses sole because when a shark bites into it the fish releases a chemical into the shark's mouth. The shark hates this chemical and lets go of the fish and it swims away. Researchers are trying to find a way to duplicate this chemical to be used as a shark repellent. The other fish that sharks cannot eat are pufferfish. When a shark tries to eat one of these fish it gets into the shark's throat and blows itself up there, blocking the water from passing over the shark's gills and eventually killing the shark.
  5. Items that have been found in the stomach of sharks: nails, coats, wine bottles, suits of armor, jewelry, musical instruments and even torpedoes!

FEEDING:

  1. Meat eating sharks jaws are loosely connected to the rest of the skull at two points. As the upper jaw protrudes and is prtracted from the mouth, teeth of the lower jaw first encounter prey. The lower jaw teeth puncture and hold the prey. The upper jaw teeth slice. A shark's short jaws make the bite powerful!
    The biggest myth about sharks is that they are crazed eating machines. This is not true. Sharks eat only when they are hungry.

  2. There are also sharks that are "filter feeders". The manta ray, the whale shark, and the basking shark are all filter feeders. They feed on plankton. Since they are filter feeders they have reduced, nonfunctional teeth. They really don't need teeth at all since they don't bite to eat.

  3. Some sharks are bottom feeders. They eat things like small fish, crabs, lobsters and shrimp.
    Some sharks have become very specialized in the way they catch their food. For example, the thresher shark uses the long upper section of it's tale to corral schools of fish, just like a cowboy corrals his cattle!
    The sawfish moves its head from side to side and hits his prey with his long "saw".


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