Geoscience Reference
In-Depth Information
The soil piles defining the nest exterior also likely required its maker(s) to
pat these down and otherwise mold the rim of the nest, firming it so that it later
hardened, perhaps cemented by precipitating minerals. A firm exterior would have
been essential, as loose mounds of dirt would not have offered much protection to
the eggs: one hard rain or windstorm would have easily eroded such inept attempts
to shield their brood. The gentle slope on the interior of the nest also suggests this
area was somewhat compacted, perhaps by trampling in a grape-stomping sort of
way. However, this might have been the final action of nesting before actual brood-
ing, happening after the eggs were laid. Because the eggs were oriented vertically,
they must have been stuck into soft sediment first; a parent
Troodon
then may have
compressedthesurroundingsoiltoreinforceandstabilizethem.Regardlessofwhen
the nest interior was finished, the nest rim must have been sculpted—like hand-
building with wet clay—an action that could have been done from inside or outside
the nest.
How long did it take a
Troodon
(or pair) to make a nest? The answer depends
on whether just one or both parents were making it. If both were involved, the time
might have been halved, but as many human couples know all too well, this would
havedependedontheirlevelofcooperation(orlackthereof).Nevertheless,onecan
easily imagine cooperative digging and molding, with one parent on the inside and
theotherontheoutside,makinganesttogether,andthusdecreasingtheirlabor.Just
to compare, though, crocodilians and sea turtles normally take just a few hours to
dig a hole nest. However, this isn't the best model for how dinosaurs constructed
a ground nest, as these hole nests are less complex structurally than what the dino-
saurs made.
A more realistic estimate might be gained by looking at times required by al-
ligators and mound-nesting birds to make their egg-protecting structures. For allig-
ators, constructing a nest normally takes about 10 to 15 days. On the other hand,
mound-nestingbirdsmayneedmonthstobuildthemassive,vegetation-ladenstruc-
tures they use for burying and incubating their eggs. Some of these mounds, such
