Marine Biology

Sharks



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Sharks have powerful senses which make them highly successful predators. In addition to standard senses, they have developed a remarkable ability to pick up the electrical signals that are produced by all living things. This process is called electro-reception.

Electrical receptors are located on a shark's snout and lower jaw, where tiny pores filled with a jelly-like substance, called the ampullae of Lorenzini, pick up weak electrical fields that all living things emit when contracting their muscles. This sixth sense is so acute, sharks can find fish that are buried in mud on the ocean floor.

Sharks perceive weak changes in electrical currents that wounded or struggling creatures produce. Researchers think this is why sharks can be attracted to humans playing in the water. Their movements produce similar electrical messages as those of wounded creatures.

Researchers also believe this sixth sense helps sharks navigate the ocean, sensing the electrical field produced by ocean currents, and reading them like a map. This ability has intrigued the military, which has looked into developing a similar technology that would be far superior to sonar.

Sharks can "hear" all over their bodies. From their heads to their tails they have special organs just beneath the skin which contain sensitive hair cells. These cells are triggered by the tiniest change in water pressure caused by anything in the ocean, from other fish to humans.

Curious creatures, sharks will travel several miles to investigate potential prey. It is typical for a shark to bump things with its snout to determine whether or not it's edible. It will even take a taste bite to see.

Now in attack mode, their eyes roll back inside of the sockets or get covered by a protective membrane. Now blind, a shark relies on its extra-sensory ability to pick up electrical signals produced by prey. These signals guide the shark's jaws in the right direction.

Sharks have a sense of smell that is so powerful it is estimated they can sense one drop of blood in a million drops of water, from nearly half a mile away. It is even believed that some sharks rise to the surface of the ocean in order to smell the air.

Sharks can see in nearly every direction because their eyes are set wide apart and they constantly move their head back and forth in a zig zag motion. Like humans, they have binocular vision, which means they have depth perception and can accurately judge distance. Many species have color vision, including the Great White. Their eyes are designed to see in very little light and are 10 times more sensitive to light than humans.

http://www.enchantedlearning.com/subjects/sharks/anatomy/Senses.shtml Enchanted Learning.

Fox, Andrew. http://www.diveplanet.co.nz/greatwhitesharksensors%2Fgwssm.asp Dive Planet NZ.

Lowe, Christian. http://www.defensetech.org/archives/001256.html Defense Tech.

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  • InfoBoxCallToAction ActionArrowhttp://www.sharksavers.org/content/view/82/80
  • InfoBoxCallToAction ActionArrowhttp://www.defensetech.org/archives/001256.html
  • InfoBoxCallToAction ActionArrowhttp://www.enchantedlearning.com/subjects/sharks/anatomy/Senses.shtml
  • InfoBoxCallToAction ActionArrowhttp://www.enchantedlearning.com/subjects/sharks/anatomy/Senses.shtml
  • InfoBoxCallToAction ActionArrowhttp://www.diveplanet.co.nz/greatwhitesharksensors%2Fgwssm.asp
  • InfoBoxCallToAction ActionArrowhttp://www.defensetech.org/archives/001256.html