Geoscience Reference
In-Depth Information
Soasaresultofthisthoughtexperiment andthatoftherunning-stumbling-dy-
ing
T. rex
or a huge-booty
T. rex
, paleontologists are not expecting to find tracks of
a running
T. rex
,
Spinosaurus
,
Gigantosaurus
, or other massive theropod anytime
soon. But of course we would be delighted to be proved wrong and would be the
first to applaud anyone who discovered such a trackway.
Sitting Dinosaurs
Watch nearly any documentary film that uses CGI (computer-generated imagery)
to recreate dinosaurs in their natural Mesozoic habitats and you will almost never
see a dinosaur sitting, lying down, sleeping, or otherwise taking it easy. This is un-
derstandable on the part of the director and animators, because the attention span
of viewers would decrease in inverse proportion to the length of such a segment
and they would quickly switch the channel to watch their favorite reality-TV stars.
(Coincidentally, these “stars” will be mostly sitting, lying down, sleeping, or oth-
erwise taking it easy.) Yet dinosaurs must have slept, rested, or paused, however
briefly, in their daily activities.
How can we know for sure dinosaurs took a breather in their lives? Surpris-
ingly, the skeletal evidence is scant, although two examples are exquisite. Both of
these skeletons belong to the same species of dinosaur,
Mei long
(“soundly sleep-
ing dragon”). Each was found with its long tail wrapped around its body, looking
very much like a sleeping duck or goose. Even more amazing, the two specimens
are mirror images of each other, one with its head turned back between its left arm
and torso, and the other with its head to the right side.
A few other dinosaur skeletons, such as those of the theropod
Citipati
, have
been found preserved in sitting positions, which also might be construed as “rest-
ing.” But these were positioned over nests with eggs, hence these dinosaurs were
probably staying put to protect their eggs and died trying. As any expectant parent
can tell you, though, taking care of your potential offspring should never be con-
sidered as “resting.” For instance, some modern flightless birds such as emus stay
seated over their eggs for 50 to 60 days.
