VIVO_2-2013-en

VIVO Behavior research 15 Elephant Fish can perceive their environment and communicate with other members of their species via active electrolocation. Catfish with barbels for food search The lateral line organ is located in a single or divided line, usually easily visible centric on both sides of the fish body. Many small cavi- ties containing sensory cells register finest current changes. Salmon ready to spawn wander thousands of kilometers from the sea back into the river where they hatched from the eggs. Finest odor and taste signals as well as the mag- netic field of the Earth show them the way. A trout can detect odor and taste one million times finer than humans. Touching and “remote touching” – the lateral line organ Fish perceive mechanical stimuli via the usual receptors in the skin. Special touching organs, such as the barbels of catfish and carps, mainly support food search. Fish have an additional highly special- ized sense ideally adapted to condi- tions under water – the lateral line organ. This sensitive remote tactile sense locates pressure changes (cur- rents or shattering) in the environ- ment. Therefore a three-dimensional picture of the surroundings is being created by registering size, location and distance of an obstacle. The fish can avoid obstacles, keep distances in a shoal, notice prey or enemies, etc. Smelling and tasting Odorous and taste substances distrib- ute very well in water. Unlike at land, both senses may be considered one, as the stimulus triggering substances are always dissolved in water – so they are being tasted by definition. The nose is composed in a very simple way (only cavities), but it is astonish- ingly effective. In fish, taste receptors can be distributed not only in the mouth but also over the entire body surface (accumulated on the head and the barbels). Olfactory and taste sense are pre- dominantly used by fish for detecting food and for orientation. Fish that perform long journeys during their life, such as salmons or eels, find their way via unimaginably fine odor traces. Their sense performance is far supe- rior to that of terrestric vertebrates such as dogs. The olfactory center makes up a large part of the fish brain. Magnetic sense and electric organ Besides these impressive sensory abil- ities, some fish species additionally have a magnetic sense that allows them orientating according to the magnetic field of the Earth. In other fish, muscle cells have developed into an electric organ. It allows them – de- pending on the specificity – to catch prey, to fend off enemies or to make location and communication in murky waters possible. The sensual perception of fish may differ strongly from ours – after all we know today it does not seem less differentiated and astonishing than that of humans. ©NatalyaKudritskaya–shutterstock.com ©Kletr–shutterstock.com ©FormosanFish–shutterstock.com ©KimBriers–shutterstock.com The sensory perception of fish

VIVO_2-2013-en

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