Geoscience Reference
In-Depth Information
The sauropods had also made extensive nesting grounds, maintained on the
upper parts of the floodplains, that covered hundreds of acres and stacked on top
of one another over thousands of years. The annual visits of these huge dinosaurs
and their nurseries not only inhibited plant growth, but also imbued this area with a
bumpy surface, like clothes left under a blanket. In a recursive way, then, these co-
alescingandsuperimposednests,whichnowformedhardenedlayersseveralmeters
belowthe
Troodon
nests,madetheareaamenableforlayingeggsandraisingyoung
for later dinosaurs. Wasps, beetles, and other insects likewise were attracted to the
well-drained soils in between the
Troodon
nests. These insects burrowed into the
sand and made brooding cells, which were later occupied by their larvae and co-
coons. The former nesting horizons of the sauropods also restricted the burrowing
ofsmallmammals,whichbroughtthemclosertothesurfaceandmadethingsalittle
easier for the
Dromaeosaurus
and other predators to find them.
Yet another trace left by the sauropods was an evolutionary one, evident in
the plant communities. The hadrosaurs had been grazing on vegetation that was
the result of intense selection pressures placed on past plants by sauropods through
bothstompingandeating.Thesechangesinplantcommunitiesconsequentlyshifted
evolution in the animal communities that used them, reinventing entire ecosystems.
Thus the stage for this Cretaceous drama was constructed and its actors were
unwittingly directed by the lasting marks of these vanished sauropods and other di-
nosaurs. In this sense, traces begat traces, and the dinosaur vestiges of the past in-
fluencedthoseofthepresent,anexpansivecanvasgentlysuggestingwherethenext
brushstrokes should go.
Tracing Dinosaur Lives
Most of the scientists I know try hard not to write fiction. After all, our primary
goal each day is to understand just a bit more about whatever we study and clearly
communicateournewlyrealizedcomprehensionstoothers.Evenso,asapracticing
paleontologist, I thought that a fictional scenario would best encapsulate much of
