Journey to Tibet
MagLab scientist Yang Wang joins an expedition to unearth the oldest woolly rhino fossils ever found
By Kathleen Laufenberg
Magnet Lab geochemist Yang Wang is
known for doing complex research using highly technical equipment. Yet she's
also hiked the remote outback of Tibet
and camped under the stars in the Himalayas – all in the name of scientific discovery. Because of her
unique mix of skills, she was part of a team that uncovered
the bones of the oldest prehistoric woolly rhino ever found.
The expedition's research received international attention in
the fall of 2011 after it was published in the journal Science.
"This is a significant find," says nationally known
vertebrate paleontologist Donald Prothero of Occidental
College in Los Angeles, who studies the evolution of woolly
rhinos and other mammals.
Yang Wang in Tibet's Zanda Basin.
The team's Tibetan discovery suggests that the woolly
rhino, and perhaps other great beasts, wandered and foraged
across ancient earth in patterns not previously imagined.
"Yang played a key role in our understanding of the
paleoenvironments of the Tibetan Plateau," says expedition
leader Xiaoming Wang, the curator of vertebrate paleontology at the Natural History Museum of Los Angeles (and
no relation to Yang Wang). "Her field and lab work gave us
insights into the paleotemperature and precipitation millions of years ago.
Traveling, Indiana Jones Style
Wang's research adventure began in
2007, when she accompanied a group of paleontologists to explore one of the most isolated places on earth: the Zanda (ZAH-dah)
Basin in Tibet, at the base of the Himalaya
Mountains. The vivid blue sky and undulating mountain views stretch for miles, unhampered by trees or brush. Majestic and
wild describe this isolated landscape, yet
fail to capture its immense wonder.
But the trip was demanding.
The Zanda Basin (about the size of
Connecticut) is nearly three miles high.
To travel there, you must first acclimate
to such heights or risk altitude sickness:
difficulty breathing, confusion and other
symptoms that require immediate medical
attention.
To avoid that, Yang, a professor in the
Department of Earth, Ocean and Atmospheric Science at Florida State University, and the paleontologists from L.A.'s
Natural History Museum and the Chinese
Academy of Sciences in Beijing spent their
first three weeks in a lower-altitude basin,
the Qaidam (pronounced TIE-dong) Basin. They camped and searched for fossils
at its 1.9-mile-high elevation.
Even though it was summer, Wang often wore her long johns and warmest jackets, especially at night when temperatures
can dip below freezing. During the day,
the researchers covered their faces with
scarves, bandit-style, to guard against the
intense sun and wind.
From the Qaidam Basin, they drove
to a small town to catch a 15-hour train to
Lhasa, the capital of the Tibetan Autonomous Region. But first they stopped to eat.
"When you work at such high altitudes, you get very hungry and I was very,
very hungry," Wang, 48, says.
She filled up on the café's greasy food –
and was sick and nauseated for three days.
In Lhasa, Wang's stomach still churning, the team rented four-wheel-drive
Land Cruisers to take them on the four-day
climb up to the Zanda Basin. Along the way,
there were six police and military checkpoints, where their permits and visas were
scrutinized.
Eventually, even their cars could take
them no further. They hiked to the fossil
digs – and were rewarded with their big
find: a prehistoric creature's intact skull
and jaw. Later, the researchers would determine the age of the extinct animal using
a dating method called magnetostratigraphy – a time scale for rock layers established by measuring the magnetic properties of the rocks. The data revealed that
they had discovered a new species of ancient beast.
"This is the oldest, most primitive
woolly rhino ever found," says Wang. "We
were all very excited!"
Scientists say the prehistoric beast used its 3-foot horn to sweep away snow and reveal tasty vegetation.
A Magnificent Beast
They christened their find the Tibetan
woolly rhino (Coelodonta thibetana). Woolly rhinos are often mentioned in the same
breath with giant sloths, sabertooth cats
and woolly mammoths. And indeed, the
Tibetan woolly rhino they discovered was
an amazing beast.
When alive, it stood perhaps 6-feet tall
and 12- to 14-feet long. Its head bore two great horns: One grew from the tip of its
nose and was about 3 feet long; a much
smaller horn arose from between its eyes.
It was stocky like today's rhino, but had
long, thick hair.
Prior to the team's discovery, the oldest woolly rhino ever found was 2.6 million years old, making it an inhabitant of
the Pleistocene era (2.6 million years ago
to 11,700 years ago). The newly discovered
Tibetan woolly rhino is 3.7 million years
old, making it a member of the Pliocene
epoch (5.3 million to 2.6 million years ago).
"The new Tibetan specimens make
a convincing case that some of the coldadapted animals of the Ice Age in Eurasia
might have originated as cold-adapted animals up in the Tibetan Plateau first, then
migrated down when the entire northern
part of Eurasia was glaciated," paleontologist Prothero says.
That suggests that the woolly rhino
– and perhaps other great beasts – had
adapted to cold weather before the Ice Age
set in 2.8 million years ago.
Chemical Clues
To unlock the Tibetan woolly rhino's
lifestyle secrets, Wang examined the
chemistry of the rhino's fossilized teeth.
To do that she uses a special tool called a
mass spectrometer. (See sidebar: Secrets
of a tooth sleuth.)
"We look at the chemistry of the teeth
and bones, to see what the animals ate and
what kind of environment they lived in."
Her detailed analysis reveals that the
creature ate grasses that grew at high altitudes, which suggests that when the Ice
Age arrived, the Tibetan woolly rhino
lumbered down from the mountains into
lower altitudes.
The expedition team also found horse,
elephant and deer fossils. Most of the
bones and teeth are being kept at the Chinese Academy of Sciences in Beijing, at its
Institute of Vertebrate Paleontology and
Paleoanthropology.
Wang and other members of the team
plan to return to the basin again in 2012 –
and they hope to make more breakthroughs.
"Who knows what we might find
when we return?" she says. "With fossils,
you never know."
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