We all know that sharks are perhaps one of the wisest sea creatures making them something to be wary of when anyone voyages out to see. Sharks are intelligent creatures, using their noses and bodies to locate smells from a distance. The sense of smell may be secondary or even tertiary to us, but to sharks, this is perhaps one of their primary means of locating objects or beings around.

Sharks use the odors and turbulence to help them find their prey. This was proven in a recent study conducted by Marine Biological Laboratory in Woods Hole, MA. Here is a portion released from the said study:

“Odor plumes are complex, dynamic, three-dimensional structures used by many animal species to locate food, mates, and home sites. However, odor itself has no directional properties, so animals must use a variety of senses to get the directional information for a smell,” said Jelle Atema, professor of biology at Boston University and study co-author.

The new study examined the contribution of the olfactory system, the lateral line, and vision in odor source detection and localization in the smooth dogfish shark. The results, which appear in the June 1 issue of the Journal of Experimental Biology, show that this shark is severely handicapped in its ability to locate the source of an odor when deprived of information from its lateral line, particularly in the dark.

According to Atema, since most odor plumes disperse in patches, fish locate odor sources through a process referred to as “eddy chemotaxis,” or the tracking of odor and turbulence simultaneously.

“We might see odor and turbulent eddies in the oily wake behind a boat. A moving animal, similarly, leaves behind a trail of turbulent eddies flavored by its body odor,” explained Atema. In an eight meter flume in the lab, Atema and Jayne Gardiner, a recently graduated Boston University Marine Program (BUMP) Masters student and study co-author, created two parallel, turbulent odor plumes – one using squid scent and the other a plain seawater control. Minimally turbulent ‘oozing’ sources of squid odor and seawater control were physically separated from sources of major turbulence by placing a brick downstream from each oozing source to create two turbulent wakes with one or the other flavored with food odor. This produced four separate smell targets for the sharks to locate.

“In addition, we also tested the sharks under two light conditions – fluorescent and infrared – and in two sensory conditions – with their lateral lines intact or lesioned by streptomycin,” explained Gardiner.

The study can be read in full here – New research shows sharks use their noses and bodies to locate smells