Some people let it all hang out. So do some animals.
Not sure what this is? Bet you can at least get close with a guess.
It's a couple orangutans smooching. You can see the full image below. These primates actually do many things that humans do, which is why they were for so long so popular in Hollywood. Did you know orangutans can whistle? They can even play charades, using gestures to get a point across. They're also one of several animals — including dolphins and elephants — that use tools.
Some scientists say orangutans, not chimps, may be human's closest relatives.
I don't know why other primates kiss, but scientists say one reason why humans kiss is that, evolutionarily speaking, we can learn a lot about a potential mate from the mouth and nose — saliva and breath carry clues we don't want to miss about a person's fitness for making and nurturing offspring.