WATCH: Why do Olympians bite their gold medals?

Biting the medal is an iconic photo from every Olympics.

The gold medal winner, with the flag draped across their shoulders sinking their teeth into the gold medal.

But why do they do it?

It's a tradition from when coins became common place.

People would bite down on the gold, and if their teeth left a mark it proved it was real, as the enamel in your teeth is stronger than gold.

Of course today, it remains popular as photographers are seeking the photo of the winners.

It's also interesting to note that gold medals actually have very little gold in them.

According to Forbes, the current medals cost about $564 and contain only about 1.2% gold.

A medal made entirely of gold would cost $22,000 the last of which was awarded in 1912.

So. Now you know.