Why do Chihuahuas shiver so much?

You've seen it happen. A tiny Chihuahua stands on the sidewalk, legs stiff, whole body trembling like a leaf in a windstorm. Is it cold? Scared? Plotting world domination while conserving energy? Let's find out why these pocket-sized dogs are professional shiverers.
First, the size thing. A Chihuahua weighs about as much as a bag of flour — maybe six pounds. That's roughly forty times lighter than a Saint Bernard. When you're that small, you have a LOT of skin surface compared to your body volume. It's like being a grape instead of a watermelon. Both have skin on the outside, but the grape's insides are way closer to the cold air.
