Axolotl, sea pig, mirror spider. These are some crazy-looking critters! But no matter how bizarre or wacky, there’s a reason why animals look the way they do. These characteristics—including their colors, teeth, and behavior—help them survive. With the help of some amazing photos, Mary Kay Carson reveals that, no matter how odd, things like slime and freaky noses are more than just surface features—they’re lifesaving.