Hunting for dinosaurs showed me our place in the universe

How do you find a dinosaur?

Sounds impossible, doesn't it?

It's not, and the answer relies

on a formula that all paleontologists use,

and I'm going to tell you the secret.

First, find rocks of the right age.

Second, those rocks must be
sedimentary rocks.

And third, layers of those rocks
must be naturally exposed.

That's it. Find those three things,
and get yourself on the ground,

chances are good that you
will find fossils.

Now let me break down this formula.

Organisms exist only during
certain geological intervals,

so you have to find rocks
of the right age

depending on what your interests are.

If you want to find trilobites,
you have to find

the really, really old rocks
of the Paleozoic,

rocks between a half a billion
and a quarter billion years old.

Now, if you want to find dinosaurs,

don't look in the Paleozoic.
You won't find them.

They hadn't evolved yet.

You have to find the younger rocks
of the Mesozoic,

and in the case of dinosaurs,
between 235 and 66 million years ago.

Now, it's fairly easy to find rocks
of the right age this point

because the Earth is,

to a course degree,

geologically mapped.

This is hard-won information.

The annals of Earth's history
are written in rocks,

one chapter upon the next, such that
the oldest pages are on bottom,

and the youngest on top.

Now, were it quite that easy,
geologists would rejoice.

It's not.

The library of Earth is an old one.

It has no librarian to impose order.

Operating over vast swaths of time,

myriad geological processes
offer every possible insult

to the rocks of ages.

Most pages are destroyed
soon after being written.

Some pages are overwritten,
creating difficult to decipher palimpsests

of long-gone landscapes.

Pages that do find sanctuary
under the advancing sands of time

are never truly safe.

Unlike the Moon,
our dead, rocky companion,

the Earth is alive, pulsing with creative
and destructive forces

that power its geological metabolism.

Lunar rocks brought back
by the Apollo astronauts

all date back to about the age
of the Solar System.

Moon rocks are forever.

Earth rocks, on the other hand,
face the perils of a living lithosphere.

All will suffer ruination
through some combination

of mutilation, compression,
folding, tearing, scorching, and baking.

Thus the volumes of Earth's history
are incomplete and disheveled.

The library is vast and magnificent

but decrepit,

and it was this tattered complexity
in the rock record

that obscured its meaning
until relatively recently.

Nature provided
no card catalog for geologists.

This would have to be invented.

5,000 years after the Sumerians learned
to record their thoughts on clay tablets,

the Earth's volume remained
inscrutable to humans.

We were geologically illiterate,

unaware of the antiquity of our own planet

and ignorant of our connection
to deep time.

It wasn't until the turn
of the 19th century

that our blinders were removed,

first with the publication
of James Hutton's "Theory of the Earth,"

in which he told us that the Earth
reveals no vestige of a beginning

and no prospect of an end,

and then with the printing
of William Smith's map of Britain,

the first country-scale geological map,

giving us for the first time
predictive insight

into where certain types
of rocks might occur.

After that, you could say things like,

"If we go over there,
we should be in the Jurassic,

or if we go up over that hill,
we should find the Cretaceous."

So now, if you want to find trilobites,

get yourself a good geological map

and go to the rocks of the Paleozoic.

If you want to find dinosaurs like I do,

find the rocks of Mesozoic and go there.

Now of course, you can only make a fossil
in a sedimentary rock,

a rock made by sand and mud.

You can't have a fossil
in an igneous rock,

formed by magma like a granite,

or in a metamorphic rock
that's been heated and squeezed.

And you have to get yourself in a desert.

It's not that dinosaurs
particularly lived in deserts.

They lived on every land mass,

and in every imaginable environment.

It's that you need to go to a place
that's a desert today,

a place that doesn't have
too many plants covering up the rocks

and a place where erosion is always
exposing new bones at the surface.

So find those three things:

rocks of the right ages,

sedimentary rocks, in a desert,

and get yourself on the ground

and you literally walk

until you see a bone
sticking out of the rock.

So here's a picture that I took
in southern Patagonia,

and every pebble that you see
on the ground there

is a piece of dinosaur bone.

So when you're in that right situation,

it's not a question of whether
you're going to find fossils or not.

You're going to find fossils.

The question is, will you find something
that is scientifically significant.

And to help with that, I'm going to add
a fourth part to our formula,

which is this:

get as far away from other
paleontologists as possible.

(Laughter)

It's not that I don't like
other paleontologists.

When you go to a place
that's relatively unexplored,

you have a much better chance
of not only finding fossils

but of finding something
that's new to science.

So that's my formula
for finding dinosaurs,

and I've applied it all around the world.

In the austral summer of 2004,

I went to the bottom of South America,

to the bottom of Patagonia, Argentina,

to prospect for dinosaurs:

a place that had terrestrial
sedimentary rocks of the right age

in a desert,

a place that had been barely visited
by paleontologists.

And we found this.

This is a femur, a thigh bone,

of a giant, plant-eating dinosaur.

That bone is 2.2 meters across.

That's over seven feet long.

Now, unfortunately,
that bone was isolated.

We dug and dug and dug,

and there wasn't another bone around,

but it made us hungry to go back
the next year for more.

And on the first day
of that next field season,

I found this: another two-meter femur,
only this time not isolated,

this time associated with 145 other bones

of a giant plant-eater.

And after three more hard,
really brutal field seasons,

the quarry came to look like this,

and there you see the tail
of that great beast wrapping around me,

and the giant that lay in this grave,
the new species of dinosaur,

we would eventually call

dreadnoughtus schrani.

Dreadnoughtus was 85 feet
from snout to tail.

It stood two and a half stories
at the shoulder,

and all fleshed out in life,
it weighed 65 tons.

People ask me sometimes,
was dreadnoughtus bigger than a T-rex?

That's the mass of eight
or nine T-rex.

Now, one of the really cool things
about being a paleontologist

is when you find a new species,
you get to name it.

And I've always thought it a shame
that these giant, plant-eating dinosaurs

are too often portrayed as passive,
lumbering platters of meat

on the landscape.

They're not.

Big herbivores can be surly,
and they can be territorial.

You do not want to mess with a hippo

or a rhino or a water buffalo.

The bison in Yellowstone injure
far more people than do the grizzly bears.

So can you imagine a big bull,
65-ton dreadnoughtus

in the breeding season,

defending a territory?

That animal would have been
incredibly dangerous,

a menace to all around, and itself
would have had nothing to fear.

And thus the name dreadnoughtus,

or fears nothing.

Now, to grow so large, an animal
like dreadnoughtus would have had

to have been a model of efficiency.

That long neck and long tail help it
radiate heat into the environment,

passively controlling its temperature,

and that long neck also serves
as a super-efficient feeding mechanism.

Dreadnoughtus could stand in one place
and with that neck, clear out

a huge envelope of vegetation,

taking in tens of thousands of calories
while expending very few.

And these animals evolved
a bulldog-like wide gait stance,

giving them immense stability,

because when you're 65 tons,
when you're literally as big as a house,

the penalty for falling over is death.

Yeah, these animals are big and tough,

but they're not going
to take a blow like that,

and dreadnoughtus falls over,
ribs break and pierce lungs,

organs burst.

If you're a big, 65-ton dreadnoughtus,
you don't get to fall down in life

even once.

Now, after this particular
dreadnoughtus carcass was buried

and defleshed by a multitude of bacteria,

worms, and insects,

its bones underwent a brief metamorphosis,

exchanging molecules with the groundwater
and becoming more and more

like the entombing rock.

As layer upon layer
of sediment accumulated,

pressure from all sides weighed in
like a stony glove

whose firm and enduring grip

held each bone in a stabilizing embrace.

And then came the long nothing.

Epoch after epoch of sameness,

nonevents without number.

All the while the skeleton lay
everlasting and unchanging

in perfect equilibrium

within its rocky grave.

Meanwhile, Earth history unfolded above.

The dinosaurs would reign
for another 12 million years

before their hegemony was snuffed out
in a fiery apocalypse.

The continents drifted. The mammals rose.

The ice age came.

And then, in east Africa,

an unpromising species of ape

evolved the odd trick of sentient thought.

These brainy primates were not
particularly fast or strong,

but they excelled at covering ground,

and in a remarkable diaspora
surpassing even the dinosaurs record

of territorial conquest, they dispersed
across the planet,

ravishing every ecosystem
they encountered,

and along the way inventing culture
and metalworking and painting

and dance and music

and science

and rocket ships that would eventually
take 12 particularly excellent apes

to the surface of the moon.

With seven billion peripatetic
homo sapiens on the planet,

it was perhaps inevitable
that one of them would eventually

trod on the grave of the magnificent titan

buried beneath the badlands
of southern Patagonia.

I was that ape,

and standing there, alone in the desert,

it was not lost on me that the chance
of any one individual

entering the fossil record
is vanishingly small.

But the Earth is very, very old,

and over vast tracts of time,
the improbable becomes the probable.

That's the magic of the geological record.

Thus multitudinous creatures
living and dying on an old planet

leave behind immense numbers of fossils,
each one a small miracle,

but collectively inevitable.

66 million years ago,
an asteroid hits the Earth,

and wipes out the dinosaurs.

This easily might not have been,

but we only get one history,
and it's the one that we have,

but this particular reality
was not inevitable.

The tiniest perturbation
of that asteroid far from Earth

would have caused it to miss
our planet by a wide margin.

The pivotal, calamitous day during which
the dinosaurs were wiped out,

setting the stage
for the modern world as we know it,

didn't have to be.

It could've just been another day,

a Thursday perhaps,

among the 63 billion days already enjoyed

by the dinosaurs.

But over geological time,
improbable, nearly impossible events,

do occur.

Along the path from our wormy,
Cambrian ancestors

to primates dressed in suits,

innumerable forks in the road
led us to this very particular reality.

The bones of dreadnoughtus
lay underground for 77 million years.

Who could have imagined
that a single species of shrew-like mammal

living in the cracks of the dinosaur world

would evolve into sentient beings
capable of characterizing

and understanding the very dinosaurs
they must have dreaded?

I once stood at the head
of the Missouri River

and bestraddled it.

There, it's nothing more
than a gurgle of water that issues forth

from beneath a rock
in a boulder in a pasture

high in the Bitterroot Mountains.

The stream next to it
runs a few hundred yards

and ends in a small pond.

Those two streams, they look identical,

but one is an anonymous trickle of water,

and the other is the Missouri River.

Now go down to the mouth
of the Missouri, near St. Louis,

and it's pretty obvious
that that river is a big deal.

But go up into the Bitterroots,
and look at the Missouri,

and human prospection does not
allow us to see it as anything special.

Now go back to the Cretaceous Period
and look at our tiny, fuzzball ancestors,

and you would never guess that they
would amount to anything special,

and they probably wouldn't have

were it not for that pesky asteroid.

Now, make a thousand more worlds
and a thousand more solar systems

and let them run.

You will never get the same result.

No doubt, those words would be
both amazing and amazingly improbable,

but they would not be our world
and they would not have our history.

There are an infinite number of histories
that we could have had,

and we only get one, and wow,
did we ever get a good one.

Dinosaurs like dreadnoughtus were real.

Sea monsters like the mosasaur were real.

Dragonflies with a wingspan of an eagle
and pill bugs the length of a car

really existed.

Why study the ancient past?

Because it gives us perspective

and humility.

The dinosaurs died in the world's
fifth mass extinction,

snuffed out in a cosmic accident
through no fault of their own.

They didn't see it coming,
and they didn't have a choice.

We, on the other hand, do have a choice,

and the nature of the fossil record
tells us that our place on this planet

is both precarious
and potentially fleeting.

Right now, our species is propagating
an environmental disaster

of geological proportions that is so broad
and so severe, it can rightly be called

the sixth extinction.

Only unlike the dinosaurs,

we can see it coming,

and unlike the dinosaurs,

we can do something about it.

That choice is ours.

Thank you.

(Applause)