The Lilliputian lizard is near the lower limits of size in vertebrate animals. Learning about how these creatures live can put some constraints on animal morphology — if your species has eyes, a backbone and a brain, there's likely a limit to how little you can get. A different group of field biologists just announced the world's smallest frog, and they claim it is the smallest vertebrate in the world, knocking a tiny Indonesian fish off the pedestal of puniness.