FILE - This Aug. 14, 2007, file photo shows a three-dimensional
model of the early human ancestor, Australopithecus afarensis,
known as Lucy, on display at the Houston Museum of Natural Science.
It's a scientific estimation of what Lucy may have looked like in life.
A new study based on an analysis of Lucy's fossil by the University
of Texas at Austin suggests she died after falling from a tree.
Several scientists, including Lucy’s discoverer, reject that she plunged
to her death from a tree.
LOS ANGELES
(AP) -- The famous human ancestor known as Lucy walked the Earth,
but it was her tree climbing that might have led to her demise, a new
study suggests.
An analysis of her partial
skeleton reveals breaks in her right arm, left shoulder, right ankle and
left knee - injuries that researchers say resulted from falling from a
high perch such as a tree.
Lucy likely died
quickly, said John Kappelman, an anthropologist at the University of
Texas at Austin, who published the findings Monday in the journal
Nature.
"I don't think she suffered," Kappelman said.
But
several other researchers, including Lucy's discoverer, disagree. They
contend most of the cracks in Lucy's bones are well documented and came
after her death from the fossilization process and natural forces such
as erosion.
How Lucy met her end has remained a
mystery since her well-preserved fossil remains were unearthed more
than four decades ago. Her discovery was significant because it allowed
scientists to establish that ancient human ancestors walked upright
before evolving a big brain.
Lucy was a member
of Australopithecus afarensis, an early human species that lived in
Africa between about 4 million and 3 million years ago. The earliest
humans climbed trees and walked on the ground. Lucy walked upright and
occasionally used her long, dangling arms to climb trees. She was a
young adult when she died.
Tim White, a
paleoanthropologist at the University of California, Berkeley, called
the study's conclusion a
"misdiagnosis." The Texas researchers "appear
to have focused only on the cracks that they could attribute to an
imagined fall, ignoring the additional abundant cracks," White said in
an email.
The split highlights the difficulty
of pinpointing a cause of death from fossilized remains. Scientists
rarely know how early humans died because skeletons are incomplete and
bones tend to get crushed under sand and rocks.
Over the years, Lucy's discoverer Donald Johanson has tried to solve the mystery.
Lucy's
skeleton, which is 40 percent complete, was recovered in Ethiopia in
what was an ancient lake near fossilized remains of crocodiles, turtle
eggs and crab claws.
"There's no definitive proof of how she died," said Johanson of Arizona State University.
The
Texas team examined Lucy's bones and used high-tech imaging. Kappelman
said the scans revealed multiple broken bones and no signs of healing,
suggesting the injuries occurred around the time of death.
He
reconstructed her final moments: The 3-foot-6-inch (1.06-meter) Lucy
fell from at least 40 feet and hit the ground at 35 mph. She landed on
her feet before twisting and falling. Such an impact would have caused
internal organ damage. Fractures on her upper arms suggest she tried to
break her fall.
Kappelman theorized that
Lucy's walking ability may have caused her to be less adept at climbing
trees, making her more vulnerable to falling from heights.
Not
everyone agrees that her tree-climbing skills were lacking. Other
scientists point out that there have been documented falls by
chimpanzees and orangutans, which spend more time in trees than Lucy's
species.
"Without a time machine, how can one
know that she didn't just get unlucky and fall?" William Harcourt-Smith
of the American Museum of Natural History said in an email.
