Geoscience Reference
In-Depth Information
EPILOGUE
A Threatened Window
on the Ancient Past
Nature has preserved a priceless window on the past for us at Auca
Mahuevo. As a result of our crew's discoveries and investigations, it
has become possible to peer through that window and envision some
of what life was like 80 million years ago on the plains of Patagonia.
The vision that has emerged is breathtaking, and if it were possible
for us to drop in for a visit, it would be difficult for us to recognize
where we were.
Huge herds of lumbering sauropods more than forty feet long
roamed the gently sloping floodplains in search of vegetation to eat,
as South America drifted lazily to the west away from Africa, which lay
just over the horizon to the east. At some time during the year, hun-
dreds of females congregated in the flood basins and abandoned
stream channels of the Auca Mahuevo nesting colony to dig their nests
and lay their eggs. Using their enormous feet, each female scooped out
a basin about three to four feet across in the dry mud of the flood basin
or the sand of the abandoned streambeds. The nests were spaced five
to ten feet apart, and each female laid between fifteen and forty
eggs in her nest before she retreated to the periphery of the nesting
colony to stand guard or wandered off across the plains in search of
food. The parents probably did not stay near the nest to provide
much care for their young, either while the eggs were incubating or
after the embryos hatched.
Most of the year, the climate at Auca Mahuevo was dry, and the
Patagonian plains baked under the relentless Cretaceous sun. During
most nesting seasons, the sunlight warmed the eggs in the nests, pro-
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