If you've paid any attention to the Olympic games (like, ever), you'll have noticed Olympians have a tendency to gnaw on their gold medals like children with a favorite toy. So what's the deal with this ubiquitous-yet-unexplained phenomenon?
As you may or may not be aware, depending on how much Game of Thrones you watch, the practice of biting gold coinage dates back to the days when said gold coinage was still a common form of payment. Since gold is a relatively soft metal, sinking your teeth into a coin was a reliable way of determining whether your ducats were legit, or if some sly dog was trying to slip you a worthless hunk of lead that was simply gold-plated.
Now, this isn't to say today's Olympians are chomping on their medals in an effort to prove their worth (although given the fiascos at Sochi and Rio, it'd be understandable). It's actually due in large part to the wishes of photographers: having the medalist playfully bite their prize just makes for a more interesting photo, according to Olympic historian David Wallechinsky.
If that's a somewhat disappointing note to end on, consider this: there hasn't actually been a solid gold medal since the 1912 Stockholm Olympics. These days, Olympic gold medals are made of gold-plated silver that's 92.5% pure, which by a stunning coincidence happens to be the same as the silver medal -- meaning the difference between first and second is essentially cosmetic. Except for the whole "beating everyone else in a competition on the world stage" part, that is.