NARRATOR: T-Rex--
king of dinosaurs. Its fossilized secrets have now
been scientifically decoded. It had eagle eye vision, could
smell prey from 3 miles away, and his bite was a
biological weapon. Yet new evidence reveals the
T-Rex was another creature's prey. What hunted the ultimate hunter? They're the Earth's
first fighters, the ultimate predators. New discoveries in
forensic science bring to life the
prehistoric art of war. This is "Jurassic Fight Club." Go back-- way back-- 65 million years ago, to a time
when the Earth was wild, raw, and mysterious; a place
of violent upheaval and extreme change. The super continents of Laurasia
and Gondwanaland fracture, forming the lands that man
will inhabit millions of years into the future. In what will become
North America, an ocean splits the landmass. Great shifts in the
Earth's tectonic plates cause the Rocky Mountains
to form in the West, and the Appalachians
to rise in the East. Volcanoes erupt with
increased frequency. The world is in turmoil. Where South Dakota is
today, volcanic ash carpets the terrain. It's the dry season. The temperature
nears 100 degrees. A high oxygen level allows
dinosaurs, the dominant life form, to grow to immense sizes. Among these giants is the
largest predator on Earth-- Tyrannosaurus Rex-- and he's
about to engage in a colossal fight-- [roaring] --to the death. Summer, 1998-- in the harsh
badlands of Northwestern South Dakota, a group of
amateur paleontologists are conducting a
routine dig when they make a stunning discovery. They had stumbled upon a
prehistoric crime scene. They were immediately able
to determine that the remains belonged to a young T-Rex. But this was not just
an ordinary skeleton. Many of the bones
had been broken, and surrounding the skeleton
were strange, blade-like teeth. But these teeth were not
the teeth of the baby T-Rex. They were the teeth of
another, unidentified predator. How had this T-Rex died? In 1998, near the town of
Belle Fourche, South Dakota, they found what appeared
to be the skeletal remains of a relatively small dinosaur. At first they weren't
sure what they had, but the evidence started to
emerge that told them this was a young Tyrannosaurus Rex. T-Rex is a pretty rare
dinosaur, but juveniles are almost unheard of, so
its discovery was pretty significant. NARRATOR: But as
workers continue to excavate the remains, they
observed something unusual. Ribs, leg and arm bones,
and various vertebrates showed signs of injury. The sheer number of
broken bones was stunning. Something had happened here. Had another predator
killed this T-Rex? The bones indicated a
brutal battle scenario. Were paleontologists
looking at a battlefield? Tyrannosaurus Rex was the
apex predator of its time. So what animal could have taken
on and killed this young T-Rex? In the late Cretaceous,
T-Rex stood out among all other dinosaurs as
one of the deadliest on Earth. They weighed up to 7
tons, stood 16 feet tall, and measured 43 feet in length-- the size of an 18-wheeler. Its large size made
T-Rex look impressive, but modern detective work
revealed three unique features that made him a true
killing machine. The first was his eyesight. In 2006, Lawrence Witmer
of Ohio University scanned the brain cavity
of Tyrannosaurus Rex. It's an important
piece of the puzzle. We now know that T-Rex had
powerful binocular vision. LAWRENCE M. WITMER: From
the CAT scan information, we can get a sense
of the relative size of particular parts
of the brain-- the part of the brain associated
with vision and optic lobes, the part of the brain associated
with the sense of smell, or the part of the brain
associated with hearing. NARRATOR: Like an
eagle, Tyrannosaurus Rex had binocular vision. This gave it the ability to
maintain focus on a moving target. In a fight, it had no
trouble keeping its opponent within its line of sight T-Rex almost certainly had
a pretty good visual field overlap, meaning it had pretty
extensive binocular vision. What we see in the brain is that
indeed, the brain is structured to, in a sense, process
that visual information. NARRATOR: Its second feature was
its tremendously powerful jaws. With a bite force of over
3,000 pounds per square inch, it's among the strongest
in the animal kingdom-- twice the strength of
a great white shark. What controlled the teeth
and the damage those teeth inflicted were the jaw muscles,
and T-Rex just has expanded the back of the skull so that
it has a lot of musculature, so that it has the power to
actually drive those teeth right through bone, has this
unbelievable power in its jaws, separated from all
other dinosaurs-- and all other living
animals as well. NARRATOR: Its third
and most dangerous asset was its incredibly
massive teeth. No other creature
before or after has ever had spikes
designed like these. T-Rex had to use those teeth
to crunch right through bone, and so it couldn't have
narrow teeth the way the other carnivorous dinosaurs did. It had to make teeth that
were really, really wide, and would have been incredibly
damaging to anything that it bent. These are pulverizing teeth. These could pierce
through flesh. They could shatter bone,
and they're anchored by extremely deep roots. They're unlike any other
predatory dinosaurs tooth. Look at the tooth of
any predatory dinosaur-- Allosaurus, Ceratosaurus,
even Raptors. You'll find that their
teeth are more blade-like and are serrated
on front and back. Very common. But look at the tooth
of a Tyrannosaurus rex and now you're looking
at a railroad spike. NARRATOR: But those teeth
may have held something more than just a massive bite. We now know that they may
have been some of the world's first biological weapons. When Witmer studied
the skull, he saw that there were serrated
ridges in the teeth. The ridges are remarkably
similar to those of another animal
with a deadly bite-- a Komodo dragon. Another interesting
attribute about the teeth of Tyrannosaurus rex is that
the serrations on the teeth-- the fine little ridges-- perhaps, actually lodge
little bits of flesh from a previous meal. And that rotting of that
flesh would have produced a great deal of bacteria. What we're talking about here
is really bad oral hygiene. And today, we actually have
animals-- the Komodo dragon, this large gigantic lizard-- that actually has what
we call a septic bite. That actually when it bites
an animal, it, in a sense, infects it with the
bacteria in its mouth. NARRATOR: Equipped
with these weapons, it seems unlikely that
any creature would attack a Tyrannosaurus rex. Even one as small as a juvenile. So who had battled this T-Rex? To help answer this
question, paleontologists had to get a complete picture
of how T-Rex lived and fought. Step one, study its environment. When we look at the Cretaceous
environments of this part of the world, it's not all that
different than environments that we still have today. When we look at the plants,
when we look at climate, and so on, we could assume that
we were looking at something that looks very similar to
what we see in the Gulf states. Climate-wise and
everything else-wise. NARRATOR: Fossilized plants
found near the skeleton reveal that the young T-Rex
lived in an area near conifer, pine, and Magnolia trees. They also discovered
prehistoric ash, which suggests that
volcanic activity occurred on a regular basis. But in the
investigation, scientists discovered something stunning. Bones of prehistoric crocodiles
and fish were found nearby. This suggests that the
T-Rex's body had been washed into a river during flooding. It's evidence of a
violent Earth that could change without warning. After studying its environment,
step two of the investigation was to study the behavior
of Tyrannosaurus rex. Using evidence found in
the bones and modern animal behavior, scientists
pieced together how these huge dinosaurs hunted,
fought, and raised their young. Tyrannosaurus rex was
the ultimate aggressor. There's nothing that
Tyrannosaurus rex was afraid of, including its
biggest prey item, Triceratops, which had these big
formidable horns and frill to protect its neck. But there were no
other dinosaurs around that would even
give Tyrannosaurus rex a second thought
about its own safety. There's no problem, whatsoever. I can take you down. NARRATOR: And when T-Rex
took its prey down, it was fast and ugly. This is an animal that could
probably, bite and chew up a Volkswagen so anything that
got in the way of that mouth was in a lot of trouble. What they really do is
get those teeth implanted and then they rear back and
just pull everything out. Bones and flesh and guts and
whatever happens to be there. And they crunch it up
and swallow it whole. if you get in the way
of this apparatus, you're not going
to last very long. NARRATOR: Although Tyrannosaurus
rex was a powerful and deadly predator, paleontologists
now believe that they lived
and moved in packs. Over the last
decades, three dig sites have suggested that
large predators lived in family groups or parks. In Alberta, Canada, they
found several skeletons of varying sizes,
from a big meat-eater called Albertosaurus. In Utah, they found
dozens of Allosaurus' that had died at the same
time in the same place. But the best evidence to support
the idea that T-Rex lived in a family group
was made in Montana. Paleontologists discovered the
remains of several individual skeletons that suggested
that this was a family of Tyrannosaurus rex's. NARRATOR: Experts believe
that living in a family pack would have ensured the
safety of their youngest. Born very small, it took
them nearly a decade before they were big enough
to fend for themselves. When T. rex was born,
it was small enough to fit in an egg about
the size of a soccer ball. And then it spent the next 10
years or so, relatively small, less than half a ton. NARRATOR: Based on the
T-Rex traveling in packs, the investigation took a turn. Experts had to
consider the theory-- is it possible that
this juvenile T-Rex was with a sibling at the
time of the attack? The experts say it is. Based on modern birds,
I think the T-Rex had two, maybe three offspring at a time. I think the only time
they were ever left alone is when the parents
were out hunting. Once the babies
grew large enough, they could go on
the hunt with them. But until they reached that
size, they were left behind and this made them
pretty vulnerable. NARRATOR: Like modern
predators, the adults would scent mark
their territory. These scents were
designed to keep predators and other dinosaurs away. We also know that the only
thing a T-Rex would fear was a larger T-Rex. Is it possible that
this juvenile was killed by a member of its own family? The tooth design
of Tyrannosaurus rex is very distinctive
and therefore, leaves very distinctive
marks on the bones. Had this juvenile been attacked
and killed by another rex, then we would have no doubt
because there would have been little of the
skeleton remaining. But more importantly,
they would have had these huge, round
holes punched to the bones. In my opinion, a T-Rex
did not kill this baby. NARRATOR: The powerful jaws
and teeth of Tyrannosaurus rex were capable of
cracking any bone. But the lack of bite marks
in the juvenile skeleton meant only one thing. Another Tyrannosaurus was not
responsible for this attack. But these dinosaurs had
few, if any, rivals. And with two protective
parents in the family, few creatures would dare
to attack their young. Protected or not, something
killed this young Tyrannosaur. New evidence would blow this
prehistoric mystery wide open and expose the
identity of the killer. Buried deep in the ground
for millions of years, a scenario of a
lethal dinosaur attack begins to unfold
in South Dakota. The discovery of a
juvenile Tyrannosaurus rex with numerous broken
and missing bones. Investigators worked
off the theory that two T-Rex's
were in this battle. The volatile climate in
the South Dakota Badlands demanded that the bones
of the juvenile T-Rex be removed and shipped to a lab. Workers covered the bones
with layers of plaster to ensure their protection
during transport. We have to worry about changes
in the weather, for example. So we have to get the
specimens out of the ground as fast as possible and
back to the laboratory. We'll cover the top
with plaster and burlap. And basically,
that's just a jacket or some kind of a container
to hold everything together. NARRATOR: When they open
one of the plastic jackets, experts were given their first
close-up look at a vital clue from the crime scene-- the attacker's teeth. Closer inspection led to the
identity of the suspect-- Nanotyrannus. A smaller, stealthier
version of Tyrannosaurus rex. Nanotyrannus is one of
my very favorite dinosaurs. The name actually
means pygmy tyrant. And it's pretty aptly named. Because this was
one mean dinosaur. The Nanotyrannus
size Tyrannosaur would, in my opinion, be one
of the most fearsome creatures that ever lived. Because it combines the
firepower of T-Rex on a smaller scale, with a great
speed ability. NARRATOR: Nanotyrannus wasn't
just one mean dinosaur. It's also one of the
most controversial. It was originally named for
a prehistoric skull found in Montana, in 1942. Since then, experts
have differed over whether Nanotyrannus is its
own species or probably, just a juvenile T-Rex. One of the very difficult
things in all dinosaur paleontology, just because
that the animals are so rare, is to be able to
understand this thing. Is this a new species? Or is this just a juvenile
of a species we already have? NARRATOR: Those who believe
Nanotyrannus is its own species site key differences
between it and T-Rex. One is tooth design. Well, one of the remarkable
differences between Nano-T and a full blown adult T-Rex
is the structure of the teeth. Tyrannosaurus rex has
these large-- we sometimes call them banana teeth. And that they're
certainly sharp and pointy and have serrated edges,
but they're not really thin like the blade of a knife. Rather, they're more
expanded, like a banana. Whereas, a Nano-T, what we see
are teeth that are, indeed, much more knife-like. There they're much flatter. A little bit more sharply
turned back or recurred. The kinds of teeth
we see in other kinds of predatory dinosaurs. [music playing] NARRATOR: This suggests that
while a T-Rex would crush bone, Nanotyrannus would tear through
flesh in a slicing action. There's up to 17 teeth in
this part of the upper jaw in Nanotyrannus and there's only
12 or 13 in Tyrannosaurus rex. Well, that suggests to me that
these are different species of animals. And that these species
are, in fact, valid. NARRATOR: But other
paleontologists conclude something different. [music playing] Almost all of the
evidence, I think, points to it being a juvenile
and almost, certainly, a juvenile T-Rex. However, there is
some evidence in terms of CAT scans on the
inside of the skull and some of the hollow
chambers in that brain case that are a little
peculiar in Nanotyrannus. NARRATOR: And that's another
key difference between these two predators-- the shape of their brains. CAT scans performed
by Dr. Witmer gave some surprising results. So when we did a CAT
scan of T-Rex and Nano-T, it really looked like there
were some striking differences. We could see some of those
differences in the brain. Here's Tyrannosaurus rex. And when we bring up and
look at the brain of Nano-T, we really see they're
quite different. Of course, they're
different in size. Nano-T was a smaller animal. But really, some of the
differences go beyond size. NARRATOR: The size
and shape of the brain was not the only difference. Experts would discover that the
brain was actually positioned differently, as well. The brain of Nanotyrannus is
shaped in a very different way from Tyrannosaurus rex. T-Rex held its skull kind of
like this-- pretty straight on. Where Nanotyrannus
actually looked like this. And you cannot change because
that is buried deeply in bone. You're not going to
change the orientation of those semicircular
canals of the inner ear. So clearly, this was
a different animal. NARRATOR: This discovery
proved that Nanotyrannus held its skull in
a lowered position. Making it easier to focus and
strike at potential enemies. The evidence clearly
suggests that Nanotyrannus is its own species because
there's enough distinctive differences between
it and Tyrannosaurus rex to justify its name-- Nanotyrannus. NARRATOR: Today, Nanotyrannus
is considered its own species. A stealthy, aggressive predator
who could hunt down and kill juvenile T-Rex's/ It stood 7
and 1/2 feet tall, 17 feet long, and weighed about a ton. Approximately half the
overall size and up to a sixth the weight of a T-Rex. But what Nano-T lacked in
stature, it gained in speed. Nanotyrannus has much
longer, more slender legs than Tyrannosaurus rex. That means this is an
active running dinosaur. Even though Tyrannosaurus
rex can run, he's not really designed
to run all the time. Nanotyrannus is more like
a cheetah on steroids. These animals were
really, really fast. They could outrun a
Tyrannosaurus rex no problem. And that also helped them
when they're running down prey, of course. And so they could surround
something and run it to death, basically. NARRATOR: Nanotyrannus
was large enough to take on this juvenile
T-Rex and certainly able to outrun its parents. But the bones had been broken. No bite marks were
found on them. Did this mean that the
Nanotyrannus had actually killed the juvenile T-Rex? [music playing] As a smaller
animal, Nanotyrannus would not have the
same kind of bite force that a big Tyrannosaur
would have. Its jaws were relatively
longer and more elongated. And it had more teeth and that
suggests that it really never did develop the
same kind of power that a Tyrannosaurus
did pound for pound. Nanotyrannus would be a
little more careful where it bit because it wouldn't have this
great bone-crushing quality that a full-size rex would have. NARRATOR: That is why no bite
marks were found on the bones of the juvenile T-Rex. Nanotyrannus did not have the
jaw muscles or tooth design for penetrating bone. Then, another hard
look at the evidence would bring investigators
closer to the answer. When I saw the Nanotyrannus
teeth that were found next to the juvenile skeleton,
I had a pretty good idea of what had happened. But since no bite marks
were found on the bones, it was hard to say
with any real certainty that the Nanotyrannus had
actually killed the baby. But then I took a second
look at the teeth. And I realized that
these were shed teeth. That means these were
teeth that were broken off during the act of feeding. This means that Nanotyrannus
had broken his teeth while attacking his
baby Tyrannosaurus rex. NARRATOR: The teeth that
were found near the T-Rex had been shed, but were the
teeth broken during a battle? Or could the Nanotyrannus have
simply found the dead T-Rex and lost them
scavenging his remains? The prehistoric crime
scene held the answers. It's estimated that
between 75% and maybe 90% of the baby Tyrannosaurus
rex was found. If the Nanotyrannus had
been scavenging it for food, then we would expect that
the majority of the bones would have been gone. Or at least, the
skeleton would have been torn up and disarticulated. But the fact that so much
of the skeleton remained and that the pieces were
found in relative proximity to each other, tells
me that Nanotyrannus was biting the baby
T-Rex, but not eating it. NARRATOR: So one
question remained. Why would a Nanotyrannus
risk its life to attack a juvenile
T-Rex, but not eat it? Competition between predators
has existed from the beginning of time. Being able to
outcompete your opponent is a way to ensure
your survival. Being faster, smarter, stronger
gives you a competitive edge. But in the case of
Nanotyrannus, he can never compete with an
adult Tyrannosaurus rex. It has no chance of killing an
adult so killing a baby is what it needed to do to survive. But why it didn't eat
it remains a mystery. Perhaps it was buried
very quickly after death and the Nano just didn't
have time to eat it. Or maybe something
interrupted him before he could take advantage
of that potential meal. NARRATOR: The rotting corpse
of a juvenile Tyrannosaurus rex lay buried beneath mud carried
in from some prehistoric river. [music playing] Investigators were
working off the theory that two T-Rex's
were in a battle. One was taken down
by a Nanotyrannus. Evidence of the battle
and its attacker remained hidden for
65 million years. This prehistoric
crime scene will bring to life, an epic
battle between T-Rex and the T-Rex hunter. Tyrannosaurus rex was
the most feared dinosaur in North America. Only one creature would
dare enter its domain-- Nanotyrannus. The battle lines are drawn in
this life and death struggle, as Nanotyrannus tracks
down and attempts to kill a juvenile T-Rex. With an acute knowledge of
Nanotyrannus and Tyrannosaurus rex, experts began
to piece together how this dinosaur battle may
have actually been fought. Although the T-Rex
is a juvenile, it would still have
powerful muscles and tremendous strength. But would that be
enough to defend itself from an adult Nanotyrannus? When you have a Nanotyrannus
and a baby T-Rex together, you're dealing with
animals that basically, are well-adapted
in the same ways. Even though they're
the same size, Tyrannosaurus rex
is going to grow up to be a lot bigger animal. And so because of that,
the way its muscles are formed, the way its tendons
are attached to the bones, all of this is a
little bit different. They're very similar
kinds of animals from their basic structure. Their strength was
probably, very comparable. Probably, the differences
would most about to experience, if we're talking about a
youngster versus an animal that's been around
the block a few times. If an adult were
around, a Nanotyrannus would never dare
attack a juvenile rex. The only time a
fight would occur would be if the adults
were out hunting and it left the juveniles alone. Without the protection
of an adult, then a juvenile would need
to rely on its sheer bulk as a deterrent to
being attacked. Even though it's not an adult,
a young Tyrannosaurus rex is still a powerhouse. NARRATOR: The long
legs of Nanotyrannus may have given it an edge
when it came to its speed and agility. But when attacked,
the juvenile T-Rex may have been more than a match. When we compare a
Nanotyrannus versus a sub-adult Tyrannosaurus rex of
about the same size, they're going to be
extraordinarily similar in terms of their hind
limbs, their tail, and their body proportions. So they're, again, going to
be very evenly matched when it comes to speed and agility. Nanotyrannus
would have something up on the juvenile
Tyrannosaurus rex. Not only would it be more agile
because its musculature was probably, a little
bit different. But also it would have
a lot more experience than this juvenile T-Rex. So it would anticipate and be
able to make the move a lot more smoothly and more quickly,
than a juvenile Tyrannosaurus rex. Although an adult Nanotyrannus
would have been faster and more agile than a juvenile T-Rex,
the rex had one advantage and that's family support. If the rex had a sibling, it
would change the complexity of the battle very quickly. NARRATOR: With completely
different tooth design, these two dinosaurs may
have used them differently. There is no doubt that each were
effective weapons, but which would be more deadly in combat? The thin slicing
teeth of Nanotyrannus? Or the thick crushing
teeth of T-Rex? Their jaws are a
little bit different. That's how we tell
these two animals apart. Nanotyrannus has more
teeth in its jaws. Their teeth are, pretty much,
the same size as the teeth of a baby Tyrannosaurus rex. Still, the T-Rex
would probably, have had a much harder, stronger
bite than the Nanotyrannus. Nanotyrannus teeth are
more primitive in design. They're much more blade-like. Very thin. Tyrannosaurus rex
are almost equal side to side as they
are front to back. So this means that their
feeding habits were different. Nanotyrannus would strip
carcasses of bones. Tyrannosaurus rex would eat
the whole carcass, including the bones. NARRATOR: The life of a
predator depends on its ability to hunt and kill game, but
it also had to defend itself against rivals. Predatory animals have
been at war with each other since the beginning of time. We see it today in animals
like lions and hyenas. Predators don't
tolerate other predators in their same environment
because they both compete for the same food source. So any chance they have to
kill a rival, they'll take it. An adult Nanotyrannus
would have certainly taken advantage of
an unguarded juvenile because it means getting
rid of its competition. [music playing] Certainly, there are animals
similarly enough designed and comparable enough in
strength that we might expect that the experience of the adult
Nano-T would actually allow it to win the day over the
young Tyrannosaurus rex. In terms of fighting
skills, of course, this adult Nanotyrannus will
have had a lot more experience over its lifetime than this
juvenile Tyrannosaurus rex. So it may have literally
years of experience beyond what this other young
individual would have had. In my mind, there is no doubt
that Nanotyrannus would have been more than a match for a
single juvenile Tyrannosaurus rex. The real question
for me would be, what would happen if
a Nano killed a rex? Would it eat it? Or would it just
leave it and move on? After spending
energy in a fight, I would suspect that
the winner would need to recharge his batteries and
take advantage of that food source now lying at its feet. Why this Nanotyrannus
didn't eat the juvenile is a pretty
interesting question. Something happened after
the fight that prevented him from eating this baby rex. NARRATOR: Nanotyrannus
would have had an advantage over a juvenile T-Rex. But two juveniles against a
Nano have radically changed the dynamic of the fight. By studying the bone fragments
from the scene, CAT scan, and environmental evidence, and
using modern animal behavior as a guide, experts
were able to reconstruct a plausible scenario
of an epic battle. One that took place in South
Dakota, 65 million years ago. A pair of adult T-Rex's
are on the hunt. They must leave their
babies unguarded. The juveniles are unaware
of approaching danger. Leaving their young
as a very risky thing. They understand that
there's dangers out there. But they've got to leave the
young long enough to go out and hunt for prey. NARRATOR: Traveling
in search of prey, the adults could be
gone for a long period. The adults have left a
series of scent marks. The outline boundaries
for the juveniles to stay within and for all
other dinosaurs to keep out. Most dinosaurs are repelled by
this pungent scent and retreat. But one dinosaur in
particular uses the scent marks as a homing device. Nanotyrannus actively hunts
and kills young Tyrannosaurus. Not to eat, but to get
rid of the competition. These two unguarded
juveniles are at the mercy of this tyrant killer. NARRATOR: A Nanotyrannus knows
he's no match for a fully grown T-Rex. He makes sure the adults
are gone before he moves in for the kill. Senses on high alert. The two juvenile
Tyrannosaurs instinctively know that a predator approaches. They're too young to have
ever seen a Nanotyrannus, but it doesn't matter. They're hardwired to recognize
a threat and face it head on. The Nanotyrannus doesn't
just haphazardly attack. These young Tyrannosaurs have
a special defensive mechanism-- a mouth full of bacteria. The Nanotyrannus knows that a
nip from a young Tyrannosaur could potentially end its life. These are the first animals
to use biological weapons. NARRATOR: One bite full of that
bacteria and Nanotyrannus is dead from a massive infection,
if the fight doesn't kill it first. He moves in cautiously,
using his height advantage to assert his dominance. He leans in, flashing
those serrated teeth. They're hissing is a warning-- we're not backing down. The fight's on. The Nanotyrannus hangs
back, making mock lunges. It's a luring technique. If he can get them
out of the nesting area, they have no hope. The juveniles instinctively
stay in the security of the nesting area. They stand shoulder to
shoulder, facing their attacker. NARRATOR: Nanotyrannus
circles his rivals, looking for an opportunity. The little Tyrannosaurus
leaps forward and snaps his jaws and loses his footing. The Nano grabs the
young Tyrannosaurus rex behind the neck, picks him up,
and throws him like a rag doll across the forest floor. Now he's only got
one juvenile left. NARRATOR: The lone juvenile
doesn't stand a chance. The young T-Rex
seems panicked. It wants to turn and run. But instincts tell it
to stand its ground. It roars as loud as it can. This is basically,
a cry for help. It hopes that mom and dad
are near enough to hear this. The Nanotyrannus knows that
the young T-Rex has just sounded an alarm. He's got to end
this battle and he's got to get out of there quick. He leans in and decides to
go for a full frontal attack. NARRATOR: Nanotyrannus
leans in, again. Waiting to make
his lethal lunge. He's using his experience as
a veteran fighter to his best advantage. The T-Rex, a rookie warrior,
tries to match his every move. As he moves in for
the kill, Nanotyrannus feels a horrible
pain in his left leg. He looks down and there is
the second juvenile T-Rex. He's recovered from his
sling across the forest floor and he's attacking. He's bitten the
Nanotyrannus on the leg. And if that wound
becomes infected, it could end his life. NARRATOR: This time,
Nanotyrannus will make sure that the T-Rex dies. Flexing all the
power of his jaws, he clamps down with nearly
half a ton of pressure and crushes its spinal cord. He throws it to the ground. And using his foot
claw, he stops the baby. Now he knows that juvenile
Tyrannosaurus rex is dead. NARRATOR: But there's
no time to eat. One T-Rex down, Nanotyrannus
moves in for the final kill. As he leans down
to take a bite, he feels the ground
begin to vibrate. This tell-tale signs says,
there's something big and it's nearby. NARRATOR: That something big
is the adult female T-Rex returning from her hunt. When she sees what's
happened in her absence, all hell will break loose. A pair of adult Tyrannosaurus
rex's have gone on a hunt, leaving their two
juveniles unattended. In their absence, a
predatory Nanotyrannus has terrorized their offspring. Killing one and
threatening the other. But now, the ground
begins to vibrate. The sound can be
heard for miles. It's the adult female T-Rex
coming back from her hunt. She hears the very
distinctive sound of her young pleading for help. It kicks in an emotion
that's only found in female Tyrannosaurs's. Mess with my baby,
you're messing with hell. NARRATOR: Driven by
her maternal instincts, the female is the first
to arrive on the scene. The female Tyrannosaurus
knows instinctively, this is a killer of juvenile
Tyrannosaurus rex's. She's got to leap into action. She doesn't have to worry
about sizing up this opponent. She's three times bigger. She just needs to kill him. [music playing] NARRATOR: The
female T-Rex intends to distract Nanotyrannus from
the lone surviving juvenile. Nano seas her giant jaws and
sidesteps with his long legs. But the female has
accomplished the most important thing-- get herself between
her remaining juvenile and the killer of baby T-Rex's. Now the Nanotyrannus
has two options. Try to finish off the remaining
juvenile Tyrannosaurus rex or turn around and run. It decides to pit its speed and
agility against the strength of a mad Tyrannosaurus rex. He tries to flank. If he can move around quickly
enough, she cannot respond. He can go in and with
his elongated snout, grab the juvenile,
shake it in its mouth, and kill it, and flee. NARRATOR: But Nanotyrannus
underestimates his opponent. Fueled by raging
levels of adrenaline, she spins and turns,
avoiding his flanking move. The last thing he
sees are the open jaws of the female Tyrannosaurus rex. She grabs the
Nanotyrannus in her mouth. And using the bite force of
1,000 pounds per square inch, she crushes the back,
crushes the ribs, and ends the life
of this attacker. NARRATOR: But killing the Nano
isn't enough for the mother T-Rex. She wants to use
him as a message to any other Nanotyrannus
that comes into this area. Using her massive foot
claws, she rips apart the body of the Nanotyrannus. NARRATOR: Having
killed the attacker, she turns her attention to
her lone surviving offspring. [music playing] Nanotyrannus had no
chance to win this fight. He lost because he made
two fatal mistakes. Number one, it misjudged
the maneuverability of an adult Tyrannosaurus rex. Number two, he
failed to recognize that the bond between a
mother and its offspring is stronger than any weapon. NARRATOR: T-Rex may have
triumphed over Nanotyrannus in this fight. But in the ultimate battle for
survival, they would both lose. Nanotyrannus and T-Rex,
because they're in Western North America, they may
have even seen the flash of their doom. The great explosion in
the Yucatan Peninsula when an asteroid hit it,
ending the age of dinosaurs. Of course, the dinosaurs
didn't die immediately. The big meat-eaters like
T-Rex and Nanotyrannus would have actually had
a short period of time when they did really well. When the starvation starts
to hit the plant-eaters, there's a lot of meat available. And the meat-eaters can get
in there and they could gorge. And then after a while,
they're looking around, there's nothing left to eat. It was too bad for
T-Rex and Nano. They were gone, too. NARRATOR: Gone,
but not forgotten. The mystery of T-Rex
and Nanotyrannus may never be fully known. But while the search
for facts continues, this much is certain-- 65 million years
ago, giant creatures with super-sized weapons
transformed prehistoric Earth into a battlefield. In the ultimate contest of
speed versus size, size won big.
