When you step outside into the cold winter air, you may start shivering. Our bodies do this to keep us warm – our muscles tighten and loosen quickly, creating enough energy to give off heat. Humans ...

This is Scientific American’s 60-Second Science, I'm Emily Schwing. Have you ever looked up to see a hawk soar overhead, or a small chickadee flit by and wondered: How do they do that? Believe it or ...