Can chilies repel sharks?
Some people have proposed using that hotter than hot capsaicin extract for use against sharks. The idea behind one Capsicum shark repellent patent is essentially a pepper spray for sharks. Delivering a shot of Capsicum juice at a shark would irritate the fish’s gill membranes and nerves across its entire body [source: Matos and Romero]. Similar types of repellents have worked with terrestrial pests, such as deer and even bears. However, the patent application has yet to be approved, calling the invention into question. Because of the sharks’ sensory organs and the dilution of capsaicin in the water, it doesn’t seem likely that the pepper spray would deter the fish. Their noses don’t open into their respiratory systems like humans, meaning any spicy water would not enter through the nostrils [source: Parker]. They also wouldn’t ingest the water because they extract oxygen from it then release it through their gills [source: Parker]. Finally, their eyes have dual eyelids and a protective
