How Did Allosaurus Work?

This massive Jurassic-era predator may have grazed on flesh the way we pick at cheese plates. Learn about the allosaurus in this episode of BrainStuff, based on this article: https://animals.howstuffworks.com/dinosaurs/allosaurus.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio, Hey brain Stuff,
Lauren Vogelbaum. Here between about a hundred and fifty seven
and a hundred forty five million years ago, Alasaurus, a
large predatory dinosaur, stopped what's now North America and Europe.
The fossil record suggests that the beast was pretty common

(00:24):
and did we mention it was big. Full grown Allosaurus
could grow to be thirty four ft or ten and
a half meters long, nine ft or three meters tall
at the hip, and way around three point two tons.
Sherlock Holmes creators or Arthur Conan Doyle mentioned the Alosaurus
by name in his nineteen twelve science fiction adventure novel

(00:44):
The Lost World. Yet, even giant carnivores take their lumps.
From time to time, Ladies and gents, meet Big Al.
A sub adult Alasaurus with a killer nickname big Ol
lived in what's now North sun Troll, Wyoming. Scientists would
eventually recover of his or maybe her or skeleton. Look

(01:08):
closely at the remains and you'll find no fewer than
nineteen separate bone fractures, and somehow al sustained injuries to
multiple backbones. Towbones and ribs. There's also evidence of a
serious infection on the right foot. Big Owl was unearthed
at a Wyoming quarry. In five years later, fossil hunters

(01:29):
working in the same state found another Allosaurus skeleton that's
come to be known as big Al two, and just
like its predecessor, this specimen was pretty banged up. Many
of its bones have been fractured or otherwise damaged, only
to be re healed during the dinosaur's lifetime, although one
hip injury apparently never healed over and may have been

(01:50):
implicated in the ultimate demise of Big Al two. Other
Alosaurus fossils also bear the telltale signs of serious wounds.
To fully appreciate eate these, we beat take a step
back and consider the animals role in its environment. Allosaurus
lived during the Late Jurassic period. Back then, giant herbivore

(02:10):
dinosaurs called sauropods thundered across the planet, but we often
find their bones in close association with Alosaurus materials. At
Dinosaur National Monument, which straddles the Utah Colorado border, there's
a protected quarry where visitors can look at a jumbled
collection of fossils that's been lying together for the past

(02:31):
a hundred and forty nine million years. Besides Allosaurus remains,
this quarry includes the bones of such long necked sauropods
as Diplodocus, Camarasaurus, and a Patosaurus. Fossils belonging to the
unrelated spiky tailed plant eater Steatosaurus are also present. These
were just some of the vegetarian dinos that Allosaurus interacted with,

(02:54):
and there was competition at the buffet line. One of
its rival predators in late Jurassic North Amera Rica was
the Seratosaurus, a horn nosed carnivore that could grow over
nineteen feet or six meters long, and which had a
short cameo in the movie Jurassic Park three from two
thousand one. Compared to some other dinosaurs, Alisaurus had a

(03:16):
weak bite force. The bite of a Tyrannosaurus rex, the
famous carnivore that evolved tens of millions of years after
the last Allosaurus died out, may have been four times stronger.
Even so, Allosaurus performed well under pressure. Mathematical models show
that the beast's head could withstand lots of physical strain.

(03:37):
In Paleontologists used computer simulations to learn more about how
this dinosaur dismembered its prey. According to their research, Allosaurus
may have sometimes behaved like an overgrown falcon at dinner.
The animals skull was light and its nick muscles were peculiar,
but with their simulations, the researchers showed Alasaurus would have

(03:59):
had an see time plucking meat off of corpses by
grabbing a hunk of flesh and its jaws and then
yanking its head backwards. The falcons do the same thing today,
but while those hunting birds have flight ready wings, Alasaurus
had clawed hands. Noting their size and range of motion,
dinosaur expert Kenneth Carpenter wrote in two thousand two that

(04:22):
Allosaurus could use its arms to quote grasp moderately large
prey and pull it towards the body. So what counted
as moderately large prey for a ravenous Alasaurus Maybe beaked
herbivores like the twenty three ft or seven meter Compotosaurus
fit the bill, or perhaps juvenile sauropods. If Alosaurus hunted

(04:44):
adults auropods, scientists aren't sure how. Some species alive in
the late Jurassic were around twenty four to thirty four
times heavier than even the biggest allosaurus, so the predators
might not have bothered A few experts think Alasaurus only
targeted young, sick, or dead sauropods, leaving healthy grown ups alone.

(05:05):
On the other hand, it's possible that the dinosaur used
its serrated teeth to rip the flesh off of giant,
still living sauropods in non fatal attacks. There's a pretty
awesome name for this hypothetical feeding technique, flesh grazing. A
bite marks tell Us. Stegosaurus, for one, was on the
menu only sometimes, though attacking and armored dinosaur might not

(05:28):
have been the brightest IDEA one Alosaurus pubic bone shows
a gaping wound that matches the size and shape of
a Stegosaurus tail spike. Alosaurus has also been suspected of cannibalism.
A survey that was published in May looked at two thousand,
three hundred and sixty eight fossil bones, all were covered

(05:49):
at the same Jurrassic quarry in Colorado, almost tent bore
the bite marks of meat eating dinosaurs with serrated teeth.
Many of these not on bones belonged to sauropods and
other herbivores. However, some of them came from Alasaurus. Since
Alasaurus is also the most abundant predatory dinosaur found at

(06:10):
this dig site, it's entirely possible that we're looking at
evidence of cannibalistic behavior. Also, no discussion about Allosaurus would
be complete without mentioning Utah's mysterious Cleveland Lloyd Dinosaur Quarry
or c l d Q. Fossils of ten different dinos
species have been excavated here, including plant eaters like Stegosaurus

(06:32):
and a Patosaurus. Yet a remarkable sixty percent of all
the dinosaur bones found in the quarry were left behind
by Allosaurus. Altogether, the quarry has yielded parts of at
least forty six Allosaurus skeletons. Some were juveniles, others were
full grown adults, but they all died in the same spot.

(06:52):
And the question is why and why are the numbers
so skewed? Why is Alosaurus so overrepresented there? Several explanations
have been put forth over the years. Maybe the c
l d Q was once a Jurassic predator trap, and
basically that's a place where herbivores get caught in the

(07:12):
thick mud or another substance and then attract carnivores who
die the same way. All those bodies attract even more carnivores,
with dead and dying predators vastly outnumbering prey species. Critics
say the rarity of bite marks on the quarries dinosaur
bones is a strike against this hypothesis, though Another hypothesis

(07:35):
is that the quarry was the home of a poisoned
watering hole or a normal one that dried up, leaving
thirsty dinosaurs to die on its banks, and a third
proposed scenario blames flooding for the accumulation of the skeletons.
Today's episode is based on the article Allosaurus was a

(07:57):
massive flesh grazer and possible cannibal on how stuff works
dot Com, written by Mark Vancini. Brain Stuff is production
of by Heart Radio in partnership of how stuff works
dot Com and is produced by Tyler Klang. Four more
podcasts my heart Radio, visit the i heart Radio app,
Apple Podcasts, or wherever you listen to your favorite show.