Sharks use body to trace prey

Like dogs, sharks too have a keen sense of smell. And a new study conducted on sharks reveals that nose isn't the only way sharks detects smell. In fact, their entire body, functions as a giant nose, competent enough to pick up smell.

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Fish use lateral lines to detect movement and vibration in the surrounding water. These sensitive organs can detect even the dim vibrations emitted by living things in water and also sense the three dimensional plumes of scents. Sharks use these three dimensional odor plumes to locate food, prey, mate and home sites.

The new study analyzed the contribution of the olfactory system, the lateral line, and vision in odor source detection and localization in the smooth dogfish shark. The results appear in the June 1 issue of the Journal of Experimental Biology, that shows sharks are severely handicapped in their ability to trace the source of an odor if deprived of information from its lateral line, particularly in the dark.

Since most odor plumes scatter in patches, fish locate odor sources through eddy chemotaxis, or the tracking of odor and turbulence at the same time. A moving animal, leaves behind a trail of turbulent eddies flavored by its body odor.

These results for the first time demonstrate that sharks require both olfactory as well as lateral line input for efficient and accurate tracking of odor-flavored wakes. It also revealed that visual input could improve food finding when lateral line information is not available.

The study results would surely help in understanding animal navigation under water and also guide development of autonomous underwater vehicles.

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Via: Livescience