Whoosh! Whoa! Put on the breaks, buddy. Even the world's fastest animal takes time out to smell—and slurp—the flowers. Hummingbirds live their lives in fast-forward, with hearts that beat 1,260 times a minute as they dart from bloom to bloom sipping sugary nectar. They can zip forward, backward, up, down, and even upside down on wings that flutter 70 times per second. Scientists have declared these birds the world's fastest animals relative to their body size (only insects are faster). A dive-bombing hummingbird is speedier (relatively speaking) than the space shuttle on reentry. To feed their need for speed, the birds must eat about every ten minutes, with breaks inbetween to digest.