Narrator: Lions have them, hippos have them, and even you and I have them: canines, those long, pointy front teeth. They're actually the longest teeth in the human mouth. So what are these long, sharp ...

Frightened babies expose their teeth; happy babies stretch their lips without extreme tooth exposure. Other primates expose their teeth with open mouth when threatened or with the mouth nearly closed ...

We share our sharp canine teeth with lions, hippos, and other mammals. But believe it or not, they have nothing to do with tearing into meat. Instead, our ancestors originally used them to fight for ...