I'm scared of sharkes. Is it safe to swim in the ocean when your menistrating? Does the human blood attact sharks, or are sharkes only attracted to fish blood?
Is it safe to go into the water?
Sharks have two senses that many animals do not have:
Electroreception: The Ampullae of Lorenzini are small pits in the head that detect electricity. The shark has the greatest electricity sensitivity known in all animals. This sense is used to find prey hidden in sand in bottom feeding sharks, by detecting the nerve impulses. It is this sense that sometimes confuses a shark into attacking a boat: when the metal interacts with salt water, sharks can detect the resultant electrical charge from over one mile away.
Lateral line - This system is found in most fishes, including sharks. It is used to detect motion or 'sound' in the water. The shark uses this to detect other organisms moving, especially wounded fish. The shark can 'hear' frequencies in the range of 25 to 50 Hz using this sense.
HOW TO SWIM WITH SHARKS: A PRIMER
Forward
Actually, nobody wants to swim with sharks. It is not an acknowledged sport and it is neither enjoyable nor exhilarating. These instructions are written primarily for the benefit of those, who, by virtue of their occupation, find they must swim and find that the water is infested with sharks.
It is of obvious importance to learn that the waters are shark infested before commencing to swim. It is safe to say that this initial determination has already been made. If the waters were infested, the naïve swimmer is by now probably beyond help; at the very least, he has doubtless lost any interest in learning how to swim with sharks.
Finally, swimming with sharks is like any other skill: It cannot be learned from books alone; the novice must practice in order to develop the skill. The following rules simply set forth the fundamental principles which, if followed will make it possible to survive while becoming expert through practice.
Rules
Assume all unidentified fish are sharks. Not all sharks look like sharks, and some fish that are not sharks sometimes act like sharks. Unless you have witnessed docile behavior in the presence of shed blood on more than one occasion, it is best to assume an unknown species is a shark. Inexperienced swimmers have been badly mangled by assuming that docile behavior in the absence of blood indicates that the fish is not a shark.
Do not bleed. It is a cardinal principle that if you are injured, either by accident or by intent, you must not bleed. Experience shows that bleeding prompts an even more aggressive attack and will often provoke the participation of sharks that are uninvolved or, as noted above, are usually docile.
Admittedly, it is difficult not to bleed when injured. Indeed, at first this may seem impossible. Diligent practice, however, will permit the experienced swimmer to sustain a serious laceration without bleeding and without even exhibiting any loss of composure. This hemostatic reflect can, in part, be conditioned, but there may be constitutional aspects as well. Those who cannot learn to control their bleeding should not attempt to swim with sharks, for the peril is too great.
The control of bleeding has a positive protective element for the swimmer. The shark will be confused as to whether or not his attack has injured you and confusion is to the swimmer's advantage. On the other hand, the shark may know he has injured you and be puzzled as to why you do not bleed or show distress. This also has a profound effect on sharks. They begin to question their own potency or, alternatively, believe the swimmer to have supernatural powers.
Counter any aggression promptly. Sharks rarely attack a swimmer without warning. Usually there is some tentative, exploratory aggressive action. It is important that the swimmer recognize that this behavior is a prelude to an attack and takes prompt and vigorous remedial action. The appropriate countermove is a sharp blow to the nose.