“This has been going on literally under our noses for the entire history of our association with hummingbirds and there it was,” says Rubega. “We were the first to see it.”

This same technique is also how the hummingbird swallows. Every time it extends its tongue, it presses down with its beak, squeezing the trapped nectar out. And since there’s limited space inside the beak, and the tongue is moving forward, there’s nowhere for that liberated nectar to go but backward. In this way, the tongue acts like a piston pump. As it pulls in, it brings nectar into the beak. As it shoots out, it pushes that same nectar toward the throat. The tongue even has flaps at its base, which fold out of the way as it moves forward but expand as it moves backwards, sweeping the nectar even further back.

The thing that really astonishes Rico-Guevara about all of this is that it is passive. The bird isn’t forcing its tongue open—that happens automatically when the tip enters liquid, because of the changing surface tension around it. Rico-Guevera proved that by sticking the tongue of a dead hummingbird into nectar—sure enough, it bloomed on its own. Likewise, the tongue closes automatically. It releases nectar automatically. It pushes that nectar backward automatically. The bird flicks its tongue in and out, and all else follows.

In hindsight, the surprising reality of the hummingbird tongue should have been entirely unsurprising. Almost everything about these animals is counterintuitive. Hummingbirds are the bane of easy answers. They’re where intuition goes to die.

Consider their origins. Today, hummingbirds are only found in the Americas, but fossils suggest that they originated in Eurasia, splitting off from their closest relatives—the scythe-winged swifts—around 42 million years ago. These ancestral hummingbirds likely flew over the land bridge that connected Russia and North America at the time. They fared well in the north, but they only thrived when they got to South America. In just 22 million years, those southern pioneers had diversified into hundreds of species, at least 338 of which are still alive today. And around 40 percent of those live in the Andes.

As evolutionary biologist Jim McGuire once told me, “the Andes are kind of the worst place to be a hummingbird.” Tall mountains mean thin air, which makes it harder to hover, and to get enough oxygen to fuel a gas-guzzling metabolism. And yet, the birds flourished. Their success shows no sign of stopping, either. By comparing the rates at which new species have emerged and old species go extinct, McGuire estimated that the number of hummingbird species will probably double in the next few million years.

As they evolved, they developed one of the most unusual flying styles of any bird—one that’s closer to insects. The wings of medium-sized species beat around 80 times a second, but probably not in the way you think. When I ask people to mimic a hummingbird’s wingbeats, they typically stick their hands out to the side and flap them up and down as fast as they can. That’s not how it works. Try this, instead. Press your elbows into your sides. Keep your forearms parallel to the ground and swing them in and out. Now, rotate your wrists in figure eights as you do it. Congratulations, you look ridiculous, but you’re also doing a decent impression of hummingbird flight.