aquatic plant (Ruppia cirrhosa)
were preserved above and be-
low one set of the footprints.
Scientists carbon-dated them
to at least 5,000 years earlier
than existing evidence of hu-
man settlement there.
A prevailing theory has
been that human migration
from Asia to the Americas
was impossible until Ice Age
glaciers had retreated, some-
time between 13,000 and
16,000 years ago. Evidence
of older settlements has also
been found in Chile and Texas,
which makes the footprints
at White Sands the latest
find to weaken that hypoth-
esis. If the footprints in New
Mexico were made 21,000 to
23,000 years ago (during the
Last Glacial Maximum), then
humans must have lived in the
Americas before the Ice Age.Lingering Questions
Not all scientists consider that
the dating of the seeds proves
the age of the footsteps. They
point to a phenomenon called
the freshwater reservoir effect,
in which the seeds could have
absorbed older carbon from
the lake water, making them
seem older than they are. The
study’s authors, however, say
they accounted for the reser-
voir effect and found it to be
negligible.
Loren Davis, an archaeolo-
gist at Oregon State Universi-
ty (who did not take part in the
study), said further researchwas needed to verify the ex-
tent of the reservoir effect
“given the impact and im-
portance” of the claims. If the
dating holds, it “will change
archaeological perspectives
on when people arrived
in the Americas,” he
said. While the foot-
prints do not settle the
debate, they boost the theory
that humans were in North
America earlier than was
commonly thought, although
the exact time of their first ar-
rival remains undetermined.
Looking ahead, the team is
in a race against time. “Theprints are being lost to soil
erosion,” said David Bustos,
co-author of the study. “Once
they are gone they will never
be seen again.”
—Braden PhillipsIF FURTHER STUDIES help confirm the White Sands footprints were
made by people at the peak of the last ice age 21,000 to 23,000 years
ago, it would mean that they lived alongside megafauna: mammoths,
giant sloths (pictured above right), dire wolves, and saber-toothed cats.
One set of footprints suggests the site may have been a hunting ground
with human tracks seeming to stalk those of a giant sloth. Sally Reynolds,
a paleontologist at Bournemouth University, England, and study
co-author, said humans arrived as a dominant predator. The lake
was part of a semiarid habitat, likely drawing animals and allowing
for ambush hunting. As the world warmed, however, the mega-
fauna died out. “The extinction of the megafauna may be due to
climate change and human hunting pressure,” she said.LAND OF THE LOST
ILLUSTRATION: KAREN CARRSPLASHING IN A LAKE, THESE YOUNG
PEOPLE MAY HAVE LIVED ALONGSIDE
MEGAFAUNA SOME 21,000 TO 23,
YEARS AGO IN WHAT IS TODAY’S WHITE
SANDS NATIONAL PARK, NEW MEXICO.ANCIENT SEEDS (RUPPIA CIRRHOSA)
FOUND AT THE SITE DATED THE FOOTPRINTS
TO BETWEEN 21,000 AND 23,000 YEARS AGO.
PHOTO: DAVID BUSTOS