Hummingbirds are the only birds that can fly backwards.
They can hover in place, fly sideways and reverse out of a flower. Some species beat their wings more than 50 times per second while doing it.
Why is this true?
A hummingbird's shoulder joint lets the wing rotate almost 180 degrees, so it produces lift on both the forward and the backward stroke, much like an insect. Their heart rate can exceed 1,200 beats per minute in flight.
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More about animals
Animals are the easiest place to find facts that sound invented. Three hearts, blue blood, cube-shaped droppings, a punch fast enough to boil water for an instant — every one of these is ordinary biology to the animal doing it. The collection here leans on well-documented behaviour and anatomy rather than folklore, so each entry comes with a short explanation of why the trick actually works and a source you can read next.