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dinosaurs, they are much more likely to be in saurischians, showing up in those di-
nosaurs from the Late Triassic through the Late Cretaceous, and then continuing in
birds.Thatmeansthisviewing,recognition,grabbing,andeatingofstoneshasbeen
going on in dinosaurs for nearly 200 million years, and will keep on happening as
long as birds are around and also need gastroliths.
Speakingofbirds,anothertypeofdinosaurbehaviorthatwaspossible,butdif-
ficult to test scientifically, is that parent dinosaurs taught their young by example,
showing them how to select rocks for their own internal collections. Mammals are
of course well known for passing on skills to their offspring, such as how mother
grizzlies teach their cubs to fish for salmon. But in the past few years, behavioral
scientists are gaining a greater appreciation for how some species of birds, such as
crows and ravens, learn through experimentation and watching one another, while
also imparting newly acquired knowledge to their chicks. If any dinosaurs per-
formedsimilarbehaviors,suchasteachingtheiroffspringhowtobecomerudiment-
ary geologists, then this would be a glimpse of dinosaur learning.
One way for paleontologists to test this outlandish idea—that parent dinosaurs
taught juvenile dinosaurs how to find the rocks they need—would be to look for
gastrolith-bearing skeletons of the same species and at different growth stages. For
instance, do both smaller skeletons (juveniles) and larger skeletons (adults) of the
same species bear gastroliths, or do just the adults have them? If both have gastro-
liths, are these the same types of rocks, implying that they might have been picked
out together and at the same places? What are the proportions of gastroliths to body
sizesofthejuveniles andadults:dotheycorrelate, orarethenumberssmallenough
in one of the size groups that accidental ingestion must be considered? These ques-
tions and more can be applied if gastroliths are some day found in multiple gener-
ations of the same species of dinosaur, allowing us to wonder beyond mechanistic
explanations and consider the bendability of behavior.
Gastrolith Ghosts of the Triassic
