Despite living at high elevation, the snow leopard breathes in a similar way to cat species at sea level, a new study says. Photograph by Tim Fitzharris, Minden Pictures/National Geographic
The snow leopard might rule the high reaches of the Himalaya, but they share some unexpected similarities with the humble house cat, a new study says.
Despite living at elevations of more than 16,400 feet (5,000 meters), these spotted big cats breathe in the same way as other feline species that live at sea level—notably your pet kitty.
Anyone who has ever tried to run even a short distance on a mountain
has felt the effects of high elevation. The difficulties people and
other animals have breathing isn’t due to lower oxygen, but rather low
air pressure at high altitudes. Each breath takes in less oxygen and
fewer air molecules overall.
Without adequate oxygen, mammals can't stay warm, run to chase prey,
or escape predators. To get around this, other high-dwelling animals
have evolved coping strategies—in particular, many of them have more
efficient hemoglobin, an oxygen-carrying protein in the blood.
Scientists wondered if snow leopards had the same adaptation. But the new research, published August 5 in the Journal of Experimental Biology, reveals they don't. In fact, the predators take in about half as much oxygen with each breath as they would at sea level.
"We were very surprised," said study leader Jan Janecka,
an evolutionary biologist at Duquesne University in Pittsburgh.
"Changing hemoglobin is one of the simplest ways to adapt to high
altitudes."
Mountain High
Scientists already knew that low-altitude feline species generally have hemoglobin that's not good at binding with oxygen.
Even so, Janecka and colleagues suspected that they would find
differences in the hemoglobin properties of snow leopards compared with
other cats. (Learn more about snow leopards.)
The team obtained blood samples from big cats living in various U.S.
zoos, including the African lion, tiger, leopard, panther, and of course
snow leopard. They also took blood from domestic housecats.
When the scientists looked at the genes that make hemoglobin, as well
as the protein itself, they found no differences between snow leopards
and the other cat species.
"We still don’t know how snow leopards adapted [to life at altitude].
Our study raised more questions than it answered," Janecka said.
"There Must Be Other Things Going On"
Graham Scott,
an evolutionary physiologist at McMaster University who was not
involved in the study, says it was "technically very well done and used
state-of-the art analyses."
"What’s unique about this study is that it shows us there must be
other things going on" in the leopards' ability to live at altitude, he
notes. (Learn about National Geographic's Big Cats Initiative.)
For instance, Janecka and others believe that snow leopards might
simply breathe harder to bring more oxygen into their bloodstream, and
have begun studying that theory.
"As long as the animal is getting enough oxygen, natural selection isn't picky," Scott says.
“It shows," he quipped, "that there’s more than one way to skin a cat."
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