Electroreception

Electroreceptors in the head of a shark.

Electroreception is the ability animals have to sense electrical sources. It is mostly found in aquatic or amphibious animals. This is because water helps the signals travel better than air. Some exceptions are the echidnas, cockroaches and bees. Electroreception is used in electrolocation.

Research

Until recently, people thought only vertebrates had electroreception. However, research has shown that bees use electroreception to find flowers. Electroreception is found in lampreys, cartilaginous fishes (sharks, rays, chimaeras), lungfishes, bichirs, coelacanths, sturgeons, catfishes, gymnotiformes, monotremes, and at least one species of cetacean. Fish have electroreception from their lateral lines. In most groups electroreception is used for predation. The Western long-beaked echidna has about 2,000 electroreceptors on its bill. Its relative, the duck-billed platypus, has 40,000.

Electrolocation

Electroreceptive animals use this sense to find where objects are. This is important in ecological niches where the animal cannot see. For example, animals cannot use their vision in caves, in murky water, and at night. Many fish use electric fields to find buried prey. Some shark pups "freeze" when they feel the electric signal of their predators.

Electroreception Media

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  The elephantnose fish is a weakly electric mormyrid fish which generates an electric field with its electric organ and then uses its electroreceptive knollenorgans and mormyromasts to locate nearby objects by the distortions they cause in the electric field.

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  Hans Lissmann discovered electroreception in 1950 through his observations of Gymnarchus niloticus.

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  Electroreception of Capacitative and Resistive Objects in Glass Knifefish

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  Electric eel's electric organs

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  Electric eels create electric fields powerful enough to stun prey using modified muscles. Some weakly electric knifefishes appear to mimic the electric eel's discharge patterns; this may be Batesian mimicry, to deceive predators that they are too dangerous to attack.

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  Sea Lamprey (Petromyzon marinus). From female 12 5/8 inches long.

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  Tiburonportada

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  Electric ray waveform

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  Fish4345 - Flickr - NOAA Photo Library (white background)

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  Mobula mobular

Related pages

• Lateral line
• Electric fish

Other websites

• ReefQuest Centre for Shark Research
• Electrolocation on Scholarpedia
• Video clips of Gnathonemus, Apteronotus, and Ameiurus
• Electroreception in fish, amphibians and monotremes — Map of Life, University of Cambridge