Why Do Olympic Swimmers Wear Two Caps?

In a sport where every millisecond counts, you probably don’t want to be burdened with a single ounce of unnecessary apparel. That’s why swimmers opt for Speedos, not cargo pants, and tend to shave their body hair to reduce drag.

But that minimalism usually has one exception: Many athletes opt for two swim caps.

According to Quartz, that’s because each cap meets a different need. An inner cap made of latex forms snugly with the head but can wrinkle when exposed to water and movement, creating resistance. To compensate, athletes add a silicone cap as an outer protective layer. Combined, the caps also secure goggle straps to the head.

So why not just wear silicone by itself? Because it tends to slip off when fitted directly onto the scalp. And while swimmers are usually meticulous about shaving their bodies, buzzing their hair probably wouldn’t be preferable: A stubble-ridden dome is unlikely to reduce drag more than a sleek silicone membrane.

Such a practice would also deprive the internet of Bob the Cap Catcher, a heretofore anonymous worker at the Olympic swimming venue for the Summer Games in Paris. It turns out that the silicone caps can sometimes slip off swimmers’ heads even when worn over a latex cap. When American swimmer Emma Weber lost her cap during the 100-meter breaststroke, “Bob” dove in and retrieved it while the crowd applauded and video footage of the act went viral. It’s unclear if our hero with the dad bod and tiny trunks is a professional cap catcher or merely an enthusiastic fan who was in the right place at the right time.

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A version of this story was published in 2016; it has been updated for 2024.