Great White Sharks Can Detect a Drop of Blood in an Olympic-Sized Swimming Pool

Galeophobia is a surprisingly common fear of sharks in swimming pools, though thankfully, the odds of finding a Great White in the pool are slim to none. However, if a shark were to make its way into a pool, it’d have no trouble tracking down anyone with a fresh wound. That’s because sharks boast an incredibly powerful sense of smell, and can detect a single drop of blood in an Olympic-sized swimming pool.

Olympic-sized pools hold 660,430 gallons of water, and a drop of blood would be imperceptible to the naked eye. But a shark’s nose is highly sensitive, and used solely for smelling rather than breathing. This allows some sharks to detect the smell of blood or prey at one part per 10 billion, and in many cases from hundreds of feet away — or the length of several football fields, to use another sports analogy.