Limbs can be incredibly useful. Whether it’s the wing of a bat, the elongated leg of a hopping frog or our own grasping arms, limbs have been adapted to all sorts of ecosystems and functions through ...

I want you to do something for me. Ready? Okay. Forget about your arms for a second. Go on. You can do it. Now fold them up against your body, and stick out your hands so your fingers seem to stick ...