Geoscience Reference
In-Depth Information
their environments, among the greatest that ever lived. So do toothmarks ever show
where a tyrannosaur bit into a living dinosaur?
Recall again the story at the start of this topic, in which a
Tyrannosaurus
took
a bite-sized chunk out of the tail of an
Edmontosaurus
. It turns out this is a story
based on fact, and the trace fossil evidence backing it up can be viewed publicly. In
thedinosaurhalloftheDenverMuseumofScienceandNatureisabeautifulmoun-
ted skeleton of the Late Cretaceous hadrosaur
Edmontosaurus
, flawless in nearly
every way save for one small blemish. About halfway down its tail vertebrae, on
the topsurface, its vertebral spines lookasifthey were clipped, forming asemi-cir-
cular pattern, almost as if someone used a cookie-cutter on them. When paleontolo-
gist Ken Carpenter took a close look at this oddity, he saw signs of healing around
the bone, which meant this pattern was from an injury and not from, say, verteb-
ral spines snapping off after death. The curvature and width of the wound was also
intriguing, as it was the right size and shape for the tooth row of a large theropod
dinosaur.Theonlytheropodlargeenoughtoownsuchbigjawsandthatlivedinthe
sameareaandtimeasthis
Edmontosaurus
was
Albertosaurus
,atyrannosaurclosely
related to
T. rex
, or
T. rex
itself.
This was among the first firm indicators that tyrannosaurs did indeed go after
live prey, refuting naysayers who have put forth the case that the
T. rex
was just a
lowlyscavengerversusafearsomepredator.Thereality,likemostrealities, ismuch
more nuanced. Since Carpenter's study, other healed toothmarks found in
Edmon-
tosaurus
bones, either attributed to
T. rex
or
Albertosaurus
, have both affirmed and
restored the original reputation of tyrannosaurs as predators. Both trace fossils tell
us that tyrannosaurs ate both dead and live dinosaurs; hence, these theropods prob-
ably used a mixture of predation and scavenging to feed, much like many modern
top predators today, such as African lions, grizzly bears, and hyenas.
Fine Young Cannibal Dinosaurs
Consider being armed with knowing a theropod's individual teeth sizes and shapes,
the number of teeth and spacing within its jaws, and how to interpret toothmarks.
