How Mountain Animals Survive Thin Air, Cold, and Steep Terrain

During migration across the Himalayas, bar-headed geese can keep climbing for hours. In low-oxygen experiments they responded by breathing more and speeding up their hearts. That ability suits a bird that has to deliver oxygen to hard-working flight muscles as it rises into thinner air.

This goose lives year-round in the high Andes. In low-oxygen experiments it extracted more oxygen from each breath and moved more blood with each heartbeat. The bar-headed goose responded to the same challenge by breathing harder and beating its heart faster.

This antelope of the Tibetan Plateau keeps a form of hemoglobin into adulthood that related bovids make early in life. That form binds oxygen more tightly than the typical adult form, helping the blood take up oxygen in thin air.

The vicuña’s fine coat insulates it on cold Andean grasslands. Its blood has another useful trait: hemoglobin binds oxygen tightly, helping its blood pick up oxygen in thin air. A study of highland camelids found that the vicuña’s blood bound oxygen especially strongly.

Long, coarse hairs hang over a dense woolly undercoat that helps keep a wild yak warm. On the Tibetan Plateau, yaks favor alpine meadows where they can find more forage than on the surrounding dry steppe. The animals pictured are wild yaks, a species distinct from the domestic yak.

Researchers caught a member of this species on Llullaillaco at about 22,100 feet (6,739 meters), then found evidence of other mice living above 19,700 feet (6,000 meters). The summit animal’s gut contained DNA from plants known at lower elevations. How mice find that food so far above known vegetation is still an open question.

On the Qinghai-Tibetan Plateau, these small mammals stay active through bitter winters. Researchers found that they save energy by moving less and letting their body temperatures fall. At study sites with domestic yaks, some pikas also fed on yak dung when other food was scarce.

Wind deflected upward by mountain slopes and rising warm air help carry this huge bird. In one field study, a tagged condor covered about 107 miles (172 kilometers) in more than five hours without flapping. Across the birds tracked, most flapping was recorded during takeoff.

Researchers tracking ibex in the Alps recorded lower body temperatures overnight in winter and a drop in resting heart rate, a sign of reduced energy use. The measurements suggest that the animals bask in the morning, letting sunshine help warm them again.

A mountain goat’s split hooves combine hard rims with pads that grip rock. Those feet help it cross slopes and ledges in western North America. A thick coat helps it stay warm when a cliff offers little shelter.

A long, thick tail steadies a snow leopard when it moves along rocky slopes and can wrap around its body when it rests. Its dense winter fur helps in the cold. A comparative study found that its hemoglobin binds oxygen about as tightly as the hemoglobin of other cats in the study.

The tahr’s hooves combine hard and soft surfaces that grip uneven rock. On steep Himalayan slopes these animals can graze on alpine herbs and grasses and browse shrubs below the tree line. Adult males grow a long mane around the neck and shoulders.

Rock crevices provide shelter for this Andean rodent. Researchers studying southern viscachas on the dry plateau measured a lower resting energy use and lower heat loss than expected for a mammal of its size. Those traits can help an animal save energy in a cold, dry place.