蜂鸟：空中舞者 Hummingbirds: Magic in the Air

Hummingbirds take extraordinary to a whole new level. They are the smallest warm-blooded creatures on the planet, but they are also among the fastest. With wings that beat up to 200 times every second, they are among nature’s most accomplished athletes, the only birds able to hover, fly backwards, and even upside down. Hummingbird metabolisms are set in permanent overdrive, req...