Last week we discovered beluga whales say hello by waving and blowing bubbles. Now it's the turn of sea turtles to show us their underwater greeting.
And if this YouTube video is anything to go by, the shelled ones apparently do it with a 'high five' style flipper slap.
The pair then give a perfectly timed high five before spinning around and continuing to swim together.
Unfortunately there are few details about the footage and as such we don't know where or when it was filmed... or what the turtles were celebrating with their underwater high five.