Cats are cute. That's why they're all over the Internet. That's why PawNation exists. There's no denying how adorable they are. And yet, paradoxically, cats are among nature's most perfect killers. Slinky and silent, they stalk their prey with razor-sharp claws and fangs. They're the ninjas of the animal kingdom. But no one is born a ninja. It takes practice, even for cats. That's why kittens are still so clumsy sometimes. Case in point: Here's a kitten on Day 1 of its shinobi training.