Longer than three school busses.

Ten times as heavy as an elephant.

The largest dinosaur ever

is coming back from extinction.

In 1987,

a farmer in south western Argentina

made a discovery

that shook the paleontology

world to the bones.

Six bones, to be more precise.

And they seemed to come

from the largest dinosaur

to have ever existed.

Argentinosaurus, or Argentine lizard,

lived during the middle Cretaceous period

about 90 million years ago.

They were herbivorous sauropods.

That means that they subsisted

on a diet of plants

and their bodies had distinctly long,

massive necks and tails.

And when I say massive,

I mean massive.

Though they’d start their lives

as small as 5 kg (11 lb),

over 40 years,

they would grow to be around

75,000 kg (165,000 lb).

At the peak of their growth,

they could have gained around

40 kilograms (88 lb) every day.

Whoa.

That means these dinos likely

had a never-ending appetite

that required 100,000 calories daily.

So if they were alive today,

would they eventually eat

every plant and crop on the planet?

If the Argentinosaurus

managed to stage a comeback,

they'd discover that

their old stomping grounds

in South America

would look very different than they did

so many millions of years ago.

The ecosystems that exist

in this part of the world

are completely different

than they were then.

This would pose a problem

for the voracious leafy appetite

that the Argentinosaurus had.

And they wouldn't be the only ones

with an ecosystem headache.

You would too.

They would eat so many of our trees

that they could completely alter

the world as we know it.

Along with their eating habits,

these creatures would bring chaos

and destruction everywhere they went.

Paleontologists suggest

that these dinosaurs

were a towering

17 m (57 ft) tall

and spanned 35 m (115 ft) in length.

Which is a size that continues

to baffle scientists,

who wonder how the creatures

could have managed to hold up their own

giant necks.

It's estimated that their hearts

would have needed to be able

to pump blood

as far as 12 m (40 ft)

about 50 to 60 times every minute.

Combine their stature

with their astounding weight,

and they’d destroy

just about everything in their path.

Homes, infrastructure, people.

It would be kind of like Godzilla,

only more by accident.

Especially if there were more

than one Argentinosaurus.

And you’d better believe there would be.

With these dinosaurs roaming around,

you could expect

to come across one of their nesting sites

on your next hike.

Argentinosaurus was an egg-laying species

and females could have laid anywhere

from 10 to 15 eggs at a time.

And these wouldn't be anything

like your average chicken eggs.

They'd be as large

as 30 cm (1 ft) in diameter.

It's likely that you'd need

to come up with some ways to contain

their growing population size.

Soon enough,

they could lay so many eggs that

all of South America

would be overrun by big dinos.

If only there were a way

that we could tame them

like elephants

and use them to our advantage.

But this would be a pretty dangerous task,

considering their size.

And not to mention

our lack of knowledge

about how temperamental

they could have been.

Besides,

the conditions we'd need to keep them in

would likely be inhumane.

It would involve

keeping them in contained areas

that aren't large enough to sustain them.

But of course,

we couldn't let them wildly roam

the planet wherever they wanted.

I mean, that is if you

wanted to keep living on this planet too.

You'd hopefully see conservation efforts

to provide an area for them

to wander about

and live peacefully.

Though coming up with a system

to actually contain them

would be a tough task.

Electric fences could be effective

as the Argentinosaurus lacked

natural body armor.

So they'd be vulnerable

to shocks or injuries.

But if they gathered in herds,

as paleontologists suggest they would,

then even more space

and kilometers of electric fences

could be necessary.

But this would also help

to protect them from poachers

looking to hunt down

the biggest game known to man.

It would especially protect the babies

who would be left

to fend for themselves

as soon as they were born.

Sadly, reintroducing the largest dinosaurs

to ever exist

would ultimately lead to yet

another attempt by humans

to conquer everything in nature.

So maybe we'd meet our match

with a dino

that has a little more of a craving

for our tasty human flesh.

Like if the T.rex

suddenly came back from extinction.

Well, that’s a story for another WHAT IF.