̽����ѡ

There’s a popular expression: Life is 10 percent what happens to you, 90 percent how you react. From a scientific perspective, the saying is particularly apt: While all life requires oxygen, energy, and propagation, Earth’s great diversity is revealed in the countless ways that living things respond to these basic demands.

Such is the principle underlying the American Museum of Natural History’s , “Life at the Limits,” running now through January 3, 2016. If you can squeeze past the bottleneck at the exhibit’s popular tardigrade display (tardigrades are tiny aquatic invertebrates that look like puffy aliens under the microscope), you’ll discover a slew of adaptable avians as well. “Almost every section includes an amazing bird,” John Sparks, curator of AMNH's ichthyology department and co-curator of Life at the Limits, points out.

One of the featured bird adaptations arose in the high-altitude, low-oxygen air of the Himalayas, where the blood of local people has adapted to contain an increased amount of hemoglobin and red blood cells to maximize its oxygen-carrying capacity. Similarly, the blood of the Bar-headed Goose—which , the highest mountains on Earth—has mutated hemoglobin that’s more effective at oxygen loading, Sparks says. The goose also has larger lungs than any other goose, duck, or swan species, which allow it to breath a little deeper in oxygen-thin conditions.

Another exhibit reveals an adaptation shared by different animals that live in similar environments. In the caves of Southeast Asia, Cave Swiftlets, sometimes known as “bat birds,” have adopted a crude form of echolocation—the same type of navigation used by bats and dolphins. The swiftlets throw their calls out into the darkness and use the echoes that bounce off of surfaces to guide them through the cave. Sparks says that in birds, echolocation is found only in cave-dwelling species. 

Other adaptations are much more unique. The male bowerbird is given a shout-out for its bauble-encrusted faux nest. But perhaps the most standout example among the birds at the exhibit is the ridiculous tongue of a Pileated Woodpecker. “Much like an Aye-Aye’s middle finger or an anteater’s [two-foot!] tongue,” woodpeckers have lengthy, barbed tongues to jab into holes and haul out ants, Sparks says. But what’s exceptional about this one, he adds, is not the length, but rather that it wraps around the bird’s skull. And while no scientist has been able to fully explain this rare adaptation, one idea is that it acts as a shock absorber. The tongue’s position may cushion the skull as the Pileated Woodpecker pounds its beak against hard timber.

Clearly, “life is resilient and it’s resourceful,” Sparks says. Given enough time, natural selection will elicit spectacular and astonishing solutions so that all that is unique, extreme, and even quite strange, may go on living.

* * *

“Life at the Limits: Stories of Amazing Species” is open now until January 3, 2016, at the American Museum of Natural History in New York City.

Correction: John Sparks does not work at the Sackler Institute for Comparitive Genomics as previously stated in the article. He is the curator of the museum's Department of Ichthyology and co-curator for the exhibit.