The bar-headed goose (Anser indicus) that flies over the very highest peaks of the Himalayas as it moves from India to Mongolia every year. When oxygen levels in the thin air go down as low as 7 percent, the bird’s metabolism similarly goes down to accommodate, yet its wings beat just as quick as before, researchers reported August 3 in eLife.
The goose’s high-altitude flights have been a biological enigma for more than 50 years. A mountain climber saw a bar-headed goose overhead while summiting Mount Everest way back in 1953, according to Science. Scientists wondered at how the creature could ascend nine kilometers above the earth?—two kilometers more than any other known animal flies.
Scientists have for various years known that bar-headed geese have an enhanced ability to bind oxygen to their hemoglobin. A study was done in 2009 also said that the birds have more capillaries around their pectoral muscle cells than related species that don’t rise to such heights.
Various researchers have also conducted studies on the birds at rest and while walking on a treadmill in normal and hypoxic conditions, but haven’t told how the bird’s manager to have low-oxygen levels in flight.
To cover this gap in the literature, physiologist and NASA astronaut Jessica Meir and her colleagues came up with a unique experiment: starting in 2010, the team raised 19 geese from hatchlings and gave training to them to fly in a 30-yard-long wind tunnel while fitted with physiological sensors and oxygen masks, according to The Washington Post.
The masks simulated low-, medium-, and high-altitude air conditions and the sensors recorded the birds’ heart rate, blood oxygen levels, body temperature, and metabolic rate.
The geese also retorted to more-efficient flight tactics by regulating and changing the biomechanics of their wingbeats, according to The New York Times.