Of course many of us believe that the greatest dinosaur that ever
lived was good ol T rex. So this link on our museum site will just
be about Rex. First let's say that no one really knows that much
about Tyrannosaurs rex or the king of the tyrant lizards. Why
Simply put because he or she exists no longer on our planet. That
may be good or most of us would be called snacks and a few big brats
(mac's?). So all we can do is make educated guesses from the few
dozen partial skeletons that we have found fossilized. How much
can you learn from a rock?
Actually, quite a lot when put together with other evidence such
as fossilized track-ways, other dinosaurs fossils that show interactions
with Rex (such as teeth marks), coprolites (fossilized doo do),
deductive guesses by trained and untrained paleontologists, and
comparisons with other related ancestors (such as Albertosaurus)
and modern reptiles.
One of the best descriptions of a T rex has been attributed to
noted paleontologist Robert Bakker who called it The Road Runner
from Hell. This is fairly accurate. In addition we know that the
closest living relatives are Birds and Crocodiles. By comparing
these two species we can get a very good idea of what the T rex
may have been capable of.
The following pages and links will be a compilation of many of
the thoughts on the museum's name sake dinosaur. Remember, this
is edutainment so if there are some errors, disagreements, and other
opinions; that is all part of the learning process.
TYRANNOSAURUS REX: KING OF THE TYRANT
rex lived during the Late Cretaceous, some 70million years ago. It
was one of the last living dinosaurs before the great extinction
event. It lived primarily in relatively-flat floodplains
The largest of the tyrannosaurids, it reached an awesome
adult length of 50 feet (15 meters), a height of 20 feet (6 meters),
and weighed about 7 tons (14,000 pounds).
T. rex was the largest carnivorous dinosaur.
An active hunter, it may also have scavenged in order to sustain
its substantial maintenance requirements.
is now correctly portrayed as a sleek, active carnivore,
unlike older depictions as a clumsy tail-dragger. The massive
tail was most likely held off the ground, serving as a counterbalance
when on the move. This pose was actually
proposed many decades ago when the skeleton of the first T. rex
(then called Dynamosaurus imperiosus) was mounted in the
British Museum of Natural History in London.
T. rex is certainly the most awe-inspiring of
all the dinosaurs. It has been featured in many motion
pictures, from "The Lost World" (1925) to "Jurassic Park"
(1993) and "Jurassic Park: Lost World" (1996).
More thoughts and pics on T-rex
have been some of the more recent things we have learned or think
we may have learned about the T rex? Keep in mind that because we
can never know for sure all this information is just theorizing,
though often with a lot of science behind it. For every thought
on this page you can find some scientist who will claim "It just
ain't true." And they may be right. Or then again they may be wrong.
This information is presented only to make you think. It is to make
you speculate that maybe we don't know it all yet. Keep this all
- The average T rex likely weighed in between
5 and 10 tons. But there are indications that there may have been
"trophy sized" individuals of 20 tons.
- T rex may have been able to run at speeds up
to 35 miles per hour. That is as fast as a horse. It may very
well have simply chased down its prey rather than ambushed it.
- On the other hand the bite from a large individual
would have taken out a piece of living meat from its prey that
was over 3 feet long and one foot wide and deep. Whatever got
a bite like that would not likely live and may simply have died
of shock or blood loss. This would allow the rex to walk up and
leisurely finish his or her meal.
- Even though Tyrannosaurus was quite large his
anatomy says he was very agile. Most of his prey were armored
and fast. To compensate he would have to be even faster and more
agile. While it seems odd, it was very possible that T rex could
lunge, jump off the ground (as in dodging Anklysaurs tails), and
even roll on the ground to get to or away from dinner.
- Since any kind of fight by a rex with another
of its kind would likely have ended in serious injury or death,
they may have used ritualized combat. Instead of biting they may
very well have head butted and shoved their opponent around. Rattlesnakes
and cobras neck wrestle and try and throw the other down. The
weaker of the two usually know it after just a few minutes and
leave. rex's may have evolved a similar type of less than lethal
The teeth of the tyrannosaurs
by William L. Abler.
pp. 50-51, September 1999.
attempts have been made to answer the question of whether tyrannosaurs
were active predators -- seeking out and killing their prey or were
scavengers, waiting for the opportune moment to step in and satisfy
their hunger. Joining this debate, researcher William Abler and
his colleagues have literally looked inside this amazing dinosaur's
mouth for clues and come up with some surprising results.
The enormous teeth of the tyrannosaur
would seem like the perfect killing tool with sharp points and serrations
on both the front and back edges. But when put to an actual test
of bone crushing and flesh tearing, would they live up to this perfect
Abler and his associates wondered about
the serrations seen on the teeth, and whether they would serve the
same purpose as those on common kitchen knives. Since no studies
had been done regarding knife edges, Abler set up an experiment
with serrated blades and tyrannosaur tooth edges.
By creating a series of standardized
knife edges, including a serrated edge, the scientists were able
to study cuts or tears on actual pieces of meat and simulate biting
experiences similar to those that might have been demonstrated by
The blades were "mounted on a butcher's
saw operated by cords and pulleys" that created a sawing action
on several same-sized pieces of meat. While the straight edge split
the meat, a serrated knife edge "gripped and ripped" it.
A serrated fossil tooth of the ancient
shark Carcharodon megalodon produced similar results. When a tyrannosaur
tooth was placed in the mechanism, it produced cuts similar to those
made by a smooth knife blade that was in need of sharpening. Questioning
these results, Abler wondered: if the menacing tooth edges were
not sharp, what were they for?
When comparing the serrations of the
tyrannosaur tooth with those of the ancient shark, Abler saw major
differences in the shape of the points and in the spaces between
the points, or cella. The shark's tooth had pyramidal-shaped points.
while those of tyrannosaurs were cube-like.
Putting the teeth of Albertosaurus to
the meat test, the scientists discovered food particles and grease
trapped in the cella. According to Abler, when such particles remain
in the mouth they become the sites for septic bacteria which can
result in fatal bites to victims.
This indicated that tyrannosaurs might have been able to merely
bite their victims and sit back and wait for them to succumb to
the fatal infection.
A "puncture and pull" method
of biting seemed most apparent to Abler, where the dinosaur's teeth
acted as pegs that more or less held the victim. Also, due to the
non-articulating surface of the teeth, he hypothesized that tyrannosaurs
did not chew their food but swallowed it whole.
Abler cites a study of the Indonesian
Komodo dragon (Varanus komodoensis), whose teeth are similar in
shape to those of tyrannosaurs. Ciofi's study has led the paleontologist
James O. Farlow to suggest a positive comparison between the two
animals. Since the Komodo dragon sometimes hunts by biting its prey
and then waiting for it to die through an infection of the wound,
why wouldn't this be possible in tyrannosaurs?
[People bitten by a Komodo dragon
more frequently die from sepsis than from the damage inflicted by
the wound itself. -- Ed]
Abler adds that with tightly closed
lips, tyrannosaur teeth may have pierced their own gums, which would
then have bled and nourished the septic dental bacteria. This would
have provided perfect conditions for poisoning future prey.
Breathing life into Tyrannosaurus
by Gregory M. Erickson
pp. 42-49, September1999
With an interest in form and movement
of the vertebrate animal -- and particularly how these are expressed
in the T. rex -- paleontologist Gregory Erickson delves deeply into
the predator/scavenger theories associated with this animal, taking
a somewhat different tack than Abler, whose study is also presented
in the same issue of Scientific American.
Not being one who is satisfied with
the idea that function follows form, Erickson includes himself in
the "new breed of scientists" known as paleobiologists
(Just as the Samasaurus rex is a "paleoethnoherpetologist)
. These scientists take the seemingly hard route in searching for
explanations for movement not related exclusively to the animal's
For this new breed of scientist, clues
can be found in sites where groups of dinosaur fossils are found
together, in bite marks on bones, and surprisingly -- in coprolites
(dino dung)! Using data from the early Tyrannosaurus along with
others with similar life styles, such as Albertosaurus, Gorgosaurus
and Daspletosaurus, greatly helps the investigation.
When small congregations of T. rex were
found together in a site, as was the case in the Hell Creek Formation
in eastern Montana, scientists wondered about possible group dynamics
of these creatures. Then when a group of albertosaur specimens,
presumed comparable to tyrannosaurs in social behavior, were recently
rediscovered, they knew they would have a chance to do a more in-depth
Paleontologist Philip J. Currie and
other scientists from the Royal Tyrrell Museum of Palaeontology
dove into the examination and came up with some exciting results.
Their conclusions refuted the scavenging theory when they found
no evidence that the animals had congregated to take advantage of
a mud-hole-stranded, or otherwise trapped, herbivore.
Instead, Currie hypothesized, the albertosaurs
were most likely a family group that had been killed in some sort
of natural disaster. This kind of information has helped to lay
the groundwork for determining social behavior of tyrannosaurs as
Another study by Currie and Tanke discusses
bite marks made by fighting between theropods, including T. rex.
The dinosaurs would have bitten each other, with heads at the same
level, using the sides of their mouths rather than attacking from
Bite marks discovered on a pelvis of
an adult Triceratops identified by Erickson in 1992 became the "first
definitive bite marks from a T. rex". Erickson describes the
dinosaurs' method of eating as the "puncture and pull"
technique, as does Abler, but does not think food was swallowed
In testimony to this he cites a recently
discovered 44 cm long coprolite, presumed to be from a T. rex, containing
a large amount of chewed and digested bone.
With all this information in hand,
however, researchers are still divided on whether or not T. rex
was a predator or scavenger. Erickson points out that all sides
can agree on the idea that many animal species obtain food in both
ways (e.g., the modern lion and spotted hyena), and that this is
a possibility for T. rex.
This same behavior is seen in T. rex's
relationship with a common herbivore of the Cretaceous. T. rex bite
marks found in an Edmontosaurus bone bed testify to the theropod's
scavenging behavior, while its predaceous bite marks can also be
found on the healed-over tail vertebrae of an Edmontosaurus that
escaped attack. The debate continues.