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White Shark

Research has shown that Grey Reef sharks can find food in extraordinary dilutions of:

 1/1 parts per million
 1/1 parts per billion
 1/10 parts per billion

Sharks react from a distance to the thrashing about of injured prey.
What sense do they use for this?

 Sight
 Hearing
 Pressure wave measurement
 Bio-electrics

The Lorenzian ampullae provide sharks with a really amazing sense.
Scientists currently believe that they are used for:
(More than one answer possible)

 Sensing minute changes in temperature
 Orientation to the earth’s magnetic field
 Picking up minute bio-electrical impulses (e.g. heartbeat of prey)

Sharks can detect and measure pressure waves using their lateral line organ.
Is this organ unique to sharks?

 Yes
 No


 

SENSES

Senses

Sensory information is taken up differently in the element of water than in air.

  • The density of water is 800 times that of air – this means that sound travels about four times as fast as in the atmosphere.
  • Smells are only present in bound form in water, and their distribution is mainly subject to water currents.
  • Influences created by movement (e.g. blast waves), and different electrical charges or currents are more important in water than on land.
  • The light situation under water is different than on land; the deeper one goes, the less light there is, and most bodies of waters have only very little light below a depth of about 100 m.

The senses of sharks are well-adjusted to these special conditions. For example, sharks in the twilight zone usually have large eyes that enable them to use even the weakest light in those depths. Nurse sharks in contrast have only small eyes, since they are living in the bright and shallow coastal waters. Hammerhead sharks have a particularly large number of ampullae of Lorenzini on their heads, which they use to find prey hidden in the sand, such as rays.


Graphic: Ch.Staacks