For the past two decades, scientists have been manipulating genes to grow human cells where you wouldn’t quite expect them.

They're actually the longest teeth in the human mouth. So what are these long, sharp teeth doing among our short, stubby ones? Well, contrary to popular belief, it's not for tearing and ripping meat.

It's known for showing off its razor-sharp teeth while it swims, but this isn't aggressive; it's just a case of being a mouth breather. But those teeth aren't just sharp -- they're hinged.

This menacing predator uses its long, sharp teeth as a cage to keep small fish and shrimp trapped once they’re inside its mouth. The video above, filmed by the Monterey Bay Aquarium Research ...