Paleontologist Answers Fossil Questions

I'm Dr. Kenneth Lacovara,

paleontologist and executive director

of the Edelman Fossil Park of Rowan University.

And I'm here to answer your questions from the internet.

This is fossil support.

[upbeat music]

@jennyflyrocks asks,

Do you know how tyrannosaurs' head is too big

for the rest of her?

Is it me?

Well, no, it's not you.

It has a really big head.

It needs a really big head

because tyrannosaur, Tyrannosaurus rex in particular

had the strongest bite force of any land animal

probably ever.

And to have a really strong bite,

you need a really big skull

that can house really big jaw muscles.

And it turns out that head muscles and arm muscles

compete for attachment space

around the girdle of the shoulder.

So as T. rex's bite got more ferocious, its head got bigger,

its neck muscles had to get bigger.

It needed to occupy more space on the shoulder

for its neck muscles.

Its arms got shorter and shorter and shorter.

So those comical little arms that T. rex has

with two little witchy fingers is what made possible

it's murderous bite.

@LauraBedrossian writes,

Can you comment on the science behind extracting dino DNA

from mosquitoes in amber?

Is that just 'Jurassic Park' stuff?

Yes, it is.

Amber is actually a terrible geochemical environment

to preserve DNA.

People have looked and no DNA from dinosaurs

has yet been recovered.

It seems to be too old, at least for existing technology

and/or samples.

@ClippedWings22 writes, How do fossil bones fossilize?

Are they just filled with air

or are they somehow filled with the same rock

that surrounds the fossils?

The latter.

They are filled with the same rock

that surrounds the fossils.

Here is a fossil tyrannosaur bone from Morocco.

It's Cretaceous age.

You can see that there is sediment inside the hollow bone

of the tyrannosaur.

And so what usually happens is the same rock

that is surrounding the fossil also gets inside the fossil

and it's preserved that way.

@HoltonMusicMan writes, How do fossils for fossil fuel

end up two miles beneath the surface?

Especially enough to make oil.

The fossils have to be buried in what we call

a deposition basin.

Think of a river valley

or a continental shelf off of a coastline.

As sediment accumulates in those basins,

the weight of the rocks pushes them down.

So they settle under their own weight.

The pressure increases, the heat increases,

and eventually those organics can turn into fossil fuels.

@_JustCallMe_Al_ asks, You know what's so effing cool?

The evolution of discovering what dinosaurs look like

through the years.

Well, it's true.

You know, in our understanding

of the way dinosaurs looked and behaved

has been evolving ever since we discovered dinosaurs.

When dinosaurs were first found in the mid part,

early part of the 19th century,

we didn't know what they were.

Scientists didn't understand them.

They thought they were these big slow lizard like creatures.

That's how they were first reconstructed.

In 1858,

the world's first nearly complete dinosaur skeleton

was found in Southern New Jersey just eight miles from here.

And that's when we first started to get our view

of dinosaurs as these vigorous creatures.

But they were still constructed

as these kind of living tripods.

You always saw the bipedal ones with two legs on the ground

and then their tail resting behind them

to kind of prop them up.

And then in old reconstructions, you see the giants,

the sauropods.

They're always languishing about in swamps

as though they couldn't support their great weight

with their own limbs,

that they needed the buoyancy of water.

That's not true.

The giant dinosaurs like Dreadnoughtus

or Argentinosaurus were perfectly capable

of walking on dry land with their four great limbs

and holding their neck

and their tail horizontal to the ground.

You know, one evolution that has happened

just within most of our lifetimes

is we can see it in the Jurassic movies.

So in Jurassic Park in 1993,

the idea that the meat-eating dinosaurs had feathers

was really just emerging.

So you see the velociraptor,

it's scaly, and it's also very, very big.

Velociraptor in life was lavishly feathered,

a fully feathered dinosaur, and it was tiny.

A velociraptor skull is about that big.

A velociraptor is more like a pissed-off turkey

than a giant monstrous dinosaur.

If you have a velociraptor in your kitchen,

it's more of an opportunity than a problem.

@TheBigNastyOne writes,

How exactly is crude oil created from fossils?

Having a hard time wrapping my brain

around that biological process.

Well, it starts with the smallest organism.

Some people think that oil comes from dinosaurs.

Fossil fuel doesn't come from dinosaurs,

it doesn't come from some of the largest creatures.

It actually comes from some of the smallest.

It comes from plankton,

things like diatoms and foraminifera.

And as they rain down from the oceans or in deep lakes,

the layers accumulate and then they have to be buried.

They could be buried by more organic material

or they could be buried by sand or mud.

And then the pressure begins to increase,

the heat begins to increase, and they start to cook

and they turn into what we call kerogen.

Kerogen is a hard component of rock.

It's the organic component.

And if that is heated

and squeezed in just the right way,

it can turn into either petroleum or natural gas.

@geology_johnson writes, What are the oldest fossil bones?

Google says it's a 400-million year old fish.

Are bones really that young?

Geology Johnson,

I really appreciate your deep time perspective

because while 400 million years

may sound old to most people, it's really not.

If you look at the history of complex life

the last half billion years,

that's only 1/9 of Earth history.

And yes, it's true that the first ossified bones

appear in the Devonian period about 400 million years ago.

And the first function of bones was not to create skeletons.

It was probably as a reservoir of minerals.

If you're living in the ocean and the ocean chemistry

is fluctuating from one state to another,

you're going to have a tough time

getting the minerals that you need to run your metabolism.

Think of bones as a chemical battery for organisms.

You can deposit minerals in a bone,

and then later you can withdraw minerals from that bone.

It's only later that bones start to serve the function

of support as skeletons like we have today.

@TheStronkOrange writes,

How do museums make the display models for their fossils

and how accurate are the displays to their fossils?

I can speak best about what is happening here

at the Edelman Fossil Park Museum.

Our sculptor who did all of our recreations upstairs

first starts with a 1/10 scale clay maquette

of the creature he is attempting to reconstruct.

And then he 3D scans it and then he uses a CNC machine

to print out slices of it.

And that might be for a creature

that ultimately is 55 feet longer.

So, and then all those slices are glued together

and then he puts resin or other material on top of it

and then sculpts the scales individually.

He says, you know, he just start at the tail

and he starts sculpting scales

and then a couple hundred thousand scales later,

you're done.

And then it comes down

to some really artistic judgements about it.

What were the colors?

What are the ornamentations?

Were they shrink wrapped, where they blubbery?

A lot of that stuff we don't know.

But what we do is we use modern analogs.

So for example, upstairs we have a reconstruction

of a baby hadrosaur.

Now, we don't know what color baby hadrosaurs were,

but what we did is we looked at what color

and what is the patterning of a small forest herbivore.

And we looked at baby tapirs.

So we gave it the colors

and the pattern of a baby tapir,

hoping that would at least get us

a little bit closer to the truth of it.

As far as the soft parts that the animals have,

imagine like the cox comb of a chicken

or the waddle of a turkey, those things don't preserve.

And dinosaurs and other creatures must have had amazing

and extravagant soft parts that we will never know about.

A couple years ago in the Apple TV series

Prehistoric Planet was about to come out,

the consulting paleontologist contacted me

and he said we wanted to illustrate the point

that there are all these soft tissue features

that we may never know about.

So I decided to give Dreadnoughtus pop out air bladders

in its neck.

And so in the show, you see Dreadnoughtus

and then [imitates popping]

you see these popped out air bladders.

And he said, I'm sorry about this.

It was my decision and I realize

you're going to have to answer

the neck bladder question for the rest of your days.

And that is actually true.

Every time I give a talk now,

I get the neck bladder question and we have zero evidence

that Dreadnoughtus or any other dinosaur

had neck air bladders,

but it is an illustration of the point

that they probably had fantastic structures

that will never be preserved in the fossil record.

@dino4x4 asks, What's your favorite example

of conversion evolution?

Well, conversion evolution means that organisms

have landed on the same adaptation

even though they didn't inherit

those features from a common ancestor.

So think of the wings of a pterosaur and a bird

and a dragonfly.

They all have wings,

but they did not get them from a common ancestor.

They evolved them independently

because they were adapting to similar challenges.

Think of the dorsal fin of a killer whale

and the dorsal fin of a shark.

Didn't get them from the same ancestor.

You can see this in dinosaurs.

You can see it in a creature like spinosaurus,

which has a crocodile-like skull.

Not a crocodile,

but it's a fish eater as are many crocodiles.

And so it's adapting to a similar situation.

And so the evolutionary record in biology today

is just replete with examples of convergent evolution.

@caffeinatedkati writes, Did you know

there's a dinosaur named Dracorex hogwartsia?

Yes, that was named by a paleontologist named Robert Bakker.

In this museum, we have a replica of a skull on display.

Dracorex hogwartsia is a bit of a controversial dinosaur.

There are many paleontologists

that think it's actually a juvenile form

of this dinosaur right here called Pachycephalosaurus.

Either way, whether it's a juvenile Pachycephalosaurus

or its own species, it's incredible.

It's an amazing skull.

This thing looks like a dragon.

@funked_up, that's funked up asks,

How would I give myself the best chance

at becoming a fossil once I die?

Well, you need quick burial, right?

You can't hang around on the surface

where you're gonna weather away or become scavenged.

You need to have yourself buried

in what we call a depositional basin.

So that's a place where sediment accumulates.

Don't try this on a mountaintop

because mountaintops are erosional

and you will never ever turn into a fossil.

To preserve flesh or soft tissue structures,

you wanna be in an anoxic environment,

meaning one that lacks oxygen.

That way, the microbes won't decay the flesh.

If you wanna preserve the bones,

you want a lot of iron in the system.

So the iron that's dissolved in the groundwater

can go through and mineralize out in the bones

and it helps stabilize the bones

and it turns them into a really resistant kind of material.

Don't try to become a fossil in California or Costa Rica

or in Iceland because those are tectonic or volcanic areas.

You wanna be in a place like the bayous of Louisiana

or the Pine Barrens of New Jersey

or maybe the swamps of North Carolina,

places that are very environmentally quiet.

So nothing is going to disturb that body

as it's underground, sitting there for millions of years.

@Hughes_Matt writes, How are dinosaurs' size and shapes

determined from largely incomplete fossils?

Anyone know the answer?

Yes, I know the answer.

It's true.

Most dinosaur species are known from partial skeletons.

So for very few dinosaurs,

do we have the entire anatomy represented?

So what we do is we work with close cousins

when we don't have a particular part of the body present.

For Dreadnoughtus, for example, we only had two

of the probable 13 vertebra in its neck.

And so to estimate the length

and the proportions of its neck,

we used a close cousin from Northern Patagonia

with the unlyrical name of Futalognkosaurus.

But that dinosaur was discovered

with a nearly complete neck.

And so we used that,

and then we had very little cranial material

for Dreadnoughtus.

We just had a little piece of premaxilla and a single tooth.

So we used another close relative

that was known really only from a skull.

Dreadnoughtus on the other hand,

has a nearly complete tail section.

So other scientists that are working on this group

called the Titanosaurus who find no tailbones

or just a couple of tailbones

are probably going to use the tail of Dreadnoughtus then

to fill in the blanks.

And so we use close cousins whenever we can.

@its_me_michael writes,

How do we know what dinosaurs ate exactly

if only their bones were fossilized?

Teeth, mostly teeth.

We can really tell a lot about an animal's diet

from their teeth.

This is a crocodile called the Thoracosaurus.

It lived in the Cretaceous period.

It was actually a survivor of the extinction,

so it lived a little bit after the Cretaceous as well.

But look at these teeth.

They're not good for anything but murder.

These little spikes here are good for piercing flesh.

And you see the way they're curved back like a gaff hook?

It's a fish eater.

And so these teeth

are meant to both puncture the fish's body,

but also to keep it from swimming back out.

So they all point backwards towards the gullet.

If you look at a different kind of crocodile,

this is a very rare crocodile.

This one's called Baurusuchus.

And look at this tooth.

It has this blunt end

and this is a shell crunching crocodile.

It's picking up crabs and maybe snails and things like that

and crunching them between these anvil-like teeth.

Here's a little shark tooth

that have serrations along the edge.

So that is clearly met for ripping flesh.

So teeth are one way, coprolite are another.

Coprolite is a fancy word for fossil poop.

We have a coprolite here.

It's from we think either a turtle or a crocodile.

And what you can do with these is you can slice them open

and you can literally see this animal's last meal.

So it's direct evidence of diet.

We can also look at the isotopic signatures of teeth

and bones that can tell you what type of plants

it was eating.

It can tell you if it lived in a tropical

or a temperate environment.

And you can look at things like nitrogen isotopes

and that can tell you where it was in the food chain.

And so we can tell if it was a prey species

that ate only plants.

If it was an omnivore or if it was a predator.

Next up, what's your favorite dinosaur?

Well, I would say it's one that I discovered

and spent about 10 years of my life working on,

which I named Dreadnoughtus.

And I say that

because it really kind of became a member of the family.

So much of our world for that time

revolved around Dreadnoughtus.

My son grew up with Dreadnoughtus.

But I would say my favorite dinosaur

that I didn't discover is Spinosaurus,

which was found in the Bahariya Oasis of Egypt

about 125 years ago.

And it's this predatory dinosaur, think of a T. rex,

but kind of one that's been stretched out

with a crocodile head.

Long arms with gaff hooks at the end of it,

and then it has these huge six foot neural spines,

which most people interpret as sails

could possibly be a hump as well.

But this thing lived out in a mangrove ecosystem

in what is now the middle of the Sahara desert and ate fish.

Probably some big fish out there.

I would say maybe though my favorite fossil overall

is not a dinosaur at all,

but it's one from the Cambrian period

from the High Rockies in Canada called Pikaia.

And Pikaia is a little tiny worm-like creature.

It's about a centimeter and a half long.

It doesn't look very tough.

It's soft and squishy,

but it has some really interesting features.

Pikaia has its sensory organs concentrated anteriorly.

It has bilateral symmetry.

It has a one-way digestive system,

which I happen to think is the best kind of digestive system

and has V-shaped muscles.

Does that sound like anybody you know?

That sounds like everybody you know.

And so if it's descendants,

don't make it out of the Cambrian.

There will never be vertebrate animals.

There will never be fish or wombats or hoary bats or camels

or dinosaurs or hamsters or you.

@worthlesshope, first of all, that's sad, asks,

Which continents or areas

are the best for finding fossil records and why is that so?

Well, it depends on what you're looking for.

First, you need rocks of the right age.

If you're looking for dinosaurs, don't look at rocks

that are older than 237 million years old.

You won't find dinosaurs.

They have to be sedimentary rocks so that a fossil can form.

You won't find fossils in an igneous rock

or a metamorphic rock.

And then today, not then, but today,

it needs to be an arid environment

so that you get good exposures of those rocks.

That's why you usually see us paleontologists

working in deserts and in bad lands

'cause you can see the rocks,

and especially in bad lands, you get enough precipitation

that it doesn't grow plants that cover the rocks,

but there's enough water in the system to cause erosion,

which pushes back the hillside, always exposing new bones.

So you find those three things

and really you just walk until you see a fossil

sticking out of the rock.

That's how we do it.

We never just dig a hole and hope to get lucky.

We get ourselves in the right geological context

and then we prospect just by walking.

@spectrsknight writes,

What's the best preserved dinosaur fossil

that's been found?

Well, I would have to say Borealopelta

from the tar sands of Alberta.

This is a nodosaur, which falls in a bigger group,

ankylosaurs, armored dinosaurs.

And it was preserved in 3D.

And so you can walk into a room with this dinosaur

and it's like you're in a room with a dinosaur.

You can see the armor, the scales on this thing.

It's just incredible.

There's even some traces of pigment preserved

and it looks like it had what we call counter shading

like you can see in sharks and whales.

So it was darker on top and lighter on the bottom.

It's found in marine sediments,

even though all dinosaurs lived on land.

Oftentimes, nearshore marine sediments

do have terrestrial fossils.

These are what we call the bloat and float dinosaurs.

They die on a beach, they get swept out to sea.

At first they sink, but the body fills with the K gasses.

They float out to sea like a giant rotten meat booty.

And as the carcass decays,

parts of the skeletons start to drop to the sea floor.

@Jacdwis writes, How long does it take to form a fossil?

Not long.

The organism has to be buried very quickly

and the bones have to be stabilized

by minerals very quickly,

a process that maybe only takes weeks or months.

'Cause think about it, if it took a long time,

then the processes of decay and degradation

would destroy that carcass before it turned into a fossil.

@vics_linq writes, Scientists study fossilized raindrops

to learn about the earth's atmosphere.

Who ever thought raindrops could fossilize?

It's amazing, isn't it?

The geological record preserves the longest spans of time,

but also sometimes almost the shortest spans.

Raindrops can be preserved.

Individual footsteps can be preserved.

The landings of birds and pterosaurs can be preserved.

Imagine how long it takes for you

to make a footprint on the beach, right?

Just a second.

And if conditions are just right,

that event that occurred for one second

could be preserved for a hundred million years.

It has to be undisturbed naturally

for a small amount of time.

The chance of it happening is almost zero.

But we get to do the experiments so many times,

and deep time is so vast

that even something that has an almost zero chance,

but not zero chance of occurring, ends up happening a lot.

There's a quote that I love that goes,

Unlikely things are likely to happen

when happening happens a lot.

@Spiritual_Pie_8298 writes,

How can we guess from fossils how animals

and other creatures from millions of years ago

lived, behaved, et cetera?

And can we at all?

Yes, we can.

And more than guess, can certainly see what kind of food

an animal ate from its teeth and the way its jaws hinged

and the way they were processing food.

You can look at the feet and the hands.

If you have an eight-inch sickle claw

like Dryptosaurus,

well, you know that thing is a flesh ripper,

and it was using that to eviscerate its prey.

You're not gonna see any sickle claw

on something that's eating salad all day long.

You can tell a lot about an animal's lifestyle

from its postures.

Dinosaurs' feet are hinged

for straight ahead forward motion.

You know these were active vigorous creatures.

Contrast that with the languid,

sprawling posture of something like a lizard

or a crocodile with elbows and knees bent,

belly touching the ground, tail dragging behind,

a crocodile is always about a half a pushup away

from taking a nap.

@wetwork76 asks,

Do you think all the dragon mythology

was the result of ancient civilizations

finding dinosaur fossils or are dragons real?

Well, I don't think dragons are real,

although there are some creatures like pterosaurs

or Dracorex dinosaur that look a lot like dragons.

But I think what's really happening

is that ancient people are encountering fossils.

They don't have any context.

They don't have any structure

to interpret what they're seeing.

And so they generate stories like humans do

to explain their observations.

There's a woman named Adrienne Meor

who studies folk paleontology,

and she believes that the legend of the Griffin,

which has a lion's body and an eagle head

comes from observations of the fossils of Protoceratops.

She also thinks that the legend of the cyclops

maybe comes from miniature elephants

that used to live on the aisle of Crete.

And if you look at an elephant's skull,

they have their nose holes, their nares coalesce together,

and it's way up here, high on their head.

It looks like it has a giant eye hole

right in the center of its head

and thus, perhaps the legend of the cyclops.

@EtherGorilla wants to know,

dumb question, but why are mosasaur teeth so common?

Not a dumb question and we have some right here.

In fact, we commonly find them out there

in our fossil quarry.

There are many more mosasaur teeth

than there were ever mosasaurs.

Mosasaurs had a lot of teeth.

They produce some throughout their lifetime,

and mosasaurs lived in places where sediment accumulated.

And so when they would shed their teeth

or when the whole animal would die

and their skull would get buried,

it was much more likely for those teeth to get buried,

giving them a chance at turning into fossils.

@TreborRhurbarb writes,

They also tell us the pterosaur, basically flying dinosaur,

didn't evolve into birds,

but the dinosaurs, basically non-flying dinosaurs,

did evolve into birds

and they expect us to believe this rubbish?

No, please don't believe it

because science is not a belief system

and science does not require your belief.

However, we have a lot of evidence,

I would call it a mountain of evidence now

that birds are in fact dinosaurs.

We can see it in the evolution of their skeletons

and we can see it in preservation of feathers actually

that go along with some of these skeletal fines

that the first avian dinosaurs

evolved around 150 million years ago

and we have a really beautiful record now

of the transition from non-avian to avian dinosaurs,

leading right up to the birds today.

A parakeet, a penguin, a ruby-throated hummingbird

is a dinosaur to the same degree

that a stegosaurs or a T. rex is a dinosaur.

Being a dinosaur, just like being a mammal,

is a binary condition.

You can't be half a mammal, you can't be half a dinosaur.

Birds are dinosaurs.

Pterosaurs on the other hand,

flying reptiles, not dinosaurs.

It's a branch called Ornithodira.

And the Ornithodirans branched off

before there was the first dinosaur.

So they don't have a dinosaur in their family.

They're not at dinosaur.

@NewsParticipant writes, Do scientists have dinosaur DNA?

Can you get that from fossils or...?

We do not have dinosaur DNA.

DNA is a water soluble molecule,

so it doesn't hang around that long in geological time.

The oldest DNA that's been recovered from an individual

is about 800,000 years old.

And the oldest DNA from the environment

is about a million and a half years old.

That sounds old, but that's a long way from dinosaur time,

which is 66 million years ago.

So we don't have dinosaur DNA,

but what we do have are dinosaur proteins and blood vessels

and some other biomolecules from dinosaurs.

@thatsanace ask, How big were dinosaur eggs?

They were all little.

This giant dinosaur that you see over here, Dreadnoughtus,

which I found in South America,

that grew to be 65 tons and its eggs would've been,

you know, no bigger than maybe an ostrich egg.

All dinosaurs, when they hatched,

were no bigger than about the size of a large house cat.

And some were even a lot smaller.

And I think that's actually kind of one of the secrets

to the success of dinosaurs.

Us mammals, we scale with adult body size.

A baby elephant might be 300 pounds.

A baby blue whale might be 6,000 pounds.

But all dinosaurs start off small.

So a baby Dreadnoughtus like that is in its environment

and it's doing tiny herbivore things at first,

like rabbit-sized things.

Then it's doing sheep-sized things and cow-sized things

and elephant-sized things,

and then herd of elephant-sized things.

So this one species is able to capture this entire column

of resources from the ecosystem.

I think that has something to do

with the amazing success of the dinosaurs.

@Spooky [beeps] says,

Sometimes I think how tortoises and gators/crocodiles

are so close to being dinosaurs

and it makes me emotional.

Look at them go.

Well, I'm super glad.

Like turtles and crocodiles, I like them too,

but they're not dinosaurs.

Crocodiles are the closest living relatives

to dinosaurs today,

but they don't have a dinosaur in their family tree

nor do the turtles.

And if you don't have a dinosaur in your family,

you can't be a dinosaur.

So they're living cousins of dinosaurs today.

The only dinosaurs alive right now are birds.

So if you love turtles and crocodiles,

you should love birds as well 'cause they are dinosaurs.

@MiguelWildlife wants to know,

how to know if a fossil was a juvenile or an adult.

We can look at what we call the bone histology,

where you can look at the bone cells,

you can see how ordered they are,

and you can plug that into a formula

and you can get what we call percent senescence.

So this giant dinosaur over here, Dreadnoughtus,

when it died, it was 65 tons.

But we got a real shock

when we looked at the bone histology.

We could see that at the time that it died,

it was growing rapidly.

We honestly don't know how big these things could get.

Another way to do it

is you can look at the anatomy of the bones.

Some dinosaurs, like some hadrosaurs,

are born in what we would call an altricial state,

like a newbie baby robin where the bones are kind of spongy,

they're not quite articulated, they're soft,

indicating that they must have received parental care.

And then also, of course, you know, if you have multiples

of a species, you can look at the size

and see whether that individual is old or young.

@XwhatsgoodX asks,

If the dinosaurs were annihilated by an asteroid,

is there any evidence of the impact that's been discovered?

Oh yes.

So the crater itself has been discovered.

It's about 110 miles cross by 12 miles deep.

It sits off of Yucatan Peninsula in the Gulf of Mexico.

There's also an ejecta layer from the fallout

from the asteroid strike

that's been found all around the world.

When that asteroid hit, it blew the equivalent

of about Massachusetts.

Times 12 miles deep into near earth orbit.

And that material then down all over the planet.

To date, very few fossils have been found in that layer.

There's some fish scales in Belgium,

there's a mosasaur vertebra and a tooth in Poland,

there's some paddlefish and a dinosaur limb in North Dakota.

They appear to have spring pollen

trapped in their gill raker.

So we think the impact happened in the springtime.

We think it came in from the northeast

at about 45 or 50 degrees.

If you were on the earth the day before the asteroid hit,

you would've thought,

Well, this is how it's always gonna be.

These dinosaurs are always gonna be on top.

And then the next day,

I think they were functionally extinct

from a cosmic accident.

It's just incredible.

It gives me shivers and makes me thrilled about the fact

that I became paleontologist.

That's it, that's all the questions.

Hope you learned something.

Until next time.

[upbeat music]