It’s a questions that doesn’t often cross your mind… until you’re poised to jump off the side of a boat into the clear azure waters, that is.
There are sharks in the ocean, sure, but the likelihood of you being attacked is generally small. But what if your tampon leaks a little? Or worse, your period starts while you’re in the water? Will a shark be attracted to the smell of blood? Will you – and your fellow swimmers – become a magnet for the great white predator? The short answer is no. So no languishing on deck for you while your friends don their snorkels and dive into an underwater paradise!
Although sharks have poor eyesight, their sense of smell is the stuff legends are made of. It is ridiculously acute. They don’t breathe through their nostrils, so these two ultra sensitive holes are designed for the sole purpose of smelling. They can detect tiny amounts of gooey deliciousness – yes, including blood - in the water from literally miles away.
But contrary to popular belief, scientific consensus is that sharks are not attracted to human blood, and they certainly don’t interpret a whiff of it as a sign that it’s time to eat. What they are really sniffing for is their prey of choice, generally fish, sea lions and crustaceans or, in some cases, simply plankton.
The average menstruating woman loses about 30 to 40ml of blood over the course of several days. A scrape or cut that a swimmer or surfer might get from a piece of coral will release more blood into the water than that. Add to this the fact that menstrual blood isn't just blood – it's made up of other totally normal secretions – and your standard menstruating swimmer is going to leave behind an infinitesimal amount of blood, if indeed any at all.
If you’re still feeling nervous, be reassured by this: You have a one in 3.7 million chance of being killed by a shark and, according to National Geographic, 93 per cent of shark attacks around the world between 1580 and 2010 were on men. An average of 10 people die a year in shark attacks worldwide, usually the result of mistaken identity. Overall, people kill way more sharks than the other way around.