Legend has it that tattoos began when seven sailors from a ship called the Swallow each tattooed a swallow on his chest to mark their mutiny. Tradition, though, generally holds that a swallow tattoo is used measure how far a sailor travels. Originally, a swallow was earned every 5,000 nautical miles.

The polar bear tattoo is a rare one to find, but this means that a Sailor has crossed the Arctic Circle. Shellback Turtle: Sailors usually get this tattoo once they're initiated into Neptune's Court after successfully crossing the equator for the first time.

PIG & ROOSTER Tattooed on the feet or ankles, these emblems symbolize survival at sea. Pigs and roosters were often kept in wooden crates, making them likely to float to shore in the event of a shipwreck. A pig on the left knee and a rooster on the right foot references an old ditty: Pig on the knee, safety at sea.