Geoscience Reference
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dinosaur” isnotsolikely inmanyspecies. Because ofthiscombination oftrackway
and skeletal evidence, we now nonchalantly discuss the ecological effects of vast
herds of sauropods, hadrosaurs, and ceratopsians, or the pack-hunting behavior of
theropods, on Mesozoic ecosystems. “Strength in numbers” is a strategy used by
many animals today, from schooling in fish to herding in caribou to pack hunting in
wolves.
So let's say that paleontologists find a dinosaur tracksite with hundreds of
trackspreservedinit.Theycanthentestwhetherthesedinosaurtrackmakersmoved
together as a large group or not. This is based on whether the following questions
receive an answer of “yes” or “no”: (1) Do the tracks look alike? (2) If the tracks
look alike, do they also show variations in sizes? (3) Are the tracks all heading in
(more or less) the same direction? (4) Do the tracks show any other harmony of
movement, such as staying parallel to or following one another? (5) Do the tracks
seem to have been made at about the same time?
Here'swhatthosequestionsaretesting:Thefirst—dothetrackslookalike—is
examining whether they belong to the same dinosaur species or not. If they do have
the same basic form but also show a range of sizes (question 2) from small to large,
then they also could represent growth stages of the same species, from babies to
full-grownadults,andperhapsgenderdifferencesaswell.Thethirdquestioniskey,
then, as this sorts out whether the dinosaurs were truly moving together or not, and
not just randomly milling about. The fourth question further clarifies the third, as
it asks about more nuanced behavior such as whether dinosaurs in the group main-
tained a consistent “personal space” from one another or whether they were fol-
lowing leaders. Finally, the fifth question addresses whether these tracks were all
made by a sizeable group of dinosaurs moving through the area, as opposed to, say,
a dinosaur family consisting of just two adults and two juveniles that neurotically
walked through the same spot every day for several weeks.
Giventhisidealizeddinosaurtracksiteinmind,doanyfulfillallofthecriteria?
I think you suspect the answer to that, but let's look at a few examples anyway. The
