If Dwayne Johnson was a bird, he might be a hummingbird. Wait, what? The tiny ruby-throated hummingbird only weighs about as much as a Canadian nickel, but this species is all pecs: chest muscles make up one third of its body. That’s what allows the birds to move quickly, stop suddenly, hover, and fly backwards. In the fall, ruby-throats nearly double their weight—to a whopping seven grams—before migrating south to Central America, flying non-stop across the Gulf of Mexico.
Ruby-throated hummingbirds have 940 feathers—the fewest of any bird—but only the males have the sparkly red throats (called “gorgets”). The iridescence comes from the structure of the quills, and how the feathers reflect light, not from pigment. This is why a male’s throat only appears bright red when the sun shines directly on the feathers. Otherwise, it’s a dull rust colour. Meh.