Welcome to
one of the most formative
and terrifying time
periods ever.
The Cenozoic Era.
You'll find giant creatures
like the wooly mammoths
and megalodons
roaming the seas.
Along with some other creatures
you might be a little bit
more familiar with.
But more on that later.
Let's strap in
and travel back in time
to the Cenozoic era.
This is WHAT IF,
and here's what would happen
OK, you're now 66 million years
in the past.
You just missed
the age of dinosaurs
by a couple of million years.
They were wiped out
by a giant asteroid
and are now extinct.
But that doesn't mean that other life
hasn't found a way.
The death of the dinos
made way for new creatures to emerge.
Mammals.
Yeah, the early Cenozoic period
saw the rise of primitive mammals
that would begin to diversify
into different evolutionary niches.
Let's explore and check them out.
One of the most famous mammals
during this time was the megafauna.
These were giant creatures
that roamed the Earth.
A lot of these probably look familiar.
Go over to the colder regions of Earth,
and you'll find packs of wooly
mammoths roaming about.
These guys were 3.5 meters (11.5 feet) tall
and weighed up to 8 tons.
Ok, go over to what's now known
as Australia,
and you'll see the Diprotodon.
This is the biggest marsupial
that ever lived
and looks like a giant wombat.
And it wasn't just mammals that were giant either.
Watch out in the water
because you'll be met
with one of the most terrifying
creatures ever.
The megalodon.
This giant shark dominated
the oceans with teeth as big as 18 cm (7 in)
and a body as long as 20 meters (65 feet).
I could go on,
but we have so much more to explore.
As the rise of mammals happened, many of them went extinct.
And unfortunately, stuff like that is still going on today.
Luckily, our friends over at Planet Wild are working on solutions
to stop that from happening and you can help too, right from your couch.
Stick around till the end of the video for more info on
how you can help.
Let's check out a couple of other creatures,
and then I'm going to show you
something really cool.
The Cenozoic era also had the Glyptodon,
which was like a giant armadillo.
The megatherium,
a giant sloth and one of the largest of the mammals
and the Elasmotherium,
also known as the Siberian unicorn.
This was basically a wooly version
of a rhinoceros.
And there were a bunch more creatures.
But why were they so big?
Well, researchers have several different theories
as to why these creatures
became so massive.
One of the leading ones
is that with the dinosaurs gone,
these mammals could thrive in
open habitats,
helping them grow larger and larger
as generations progressed.
But there’s another
incredibly important mammal
they haven't mentioned yet.
And although it's not giant,
it is one of the most important.
And that's you
- well, sort of.
Human's early ancestors were primates.
With the death of dinosaurs,
the rise of primates became possible,
allowing them to evolve.
Early primates were small and weak creatures
when the Cenozoic era started.
But they had two key features
to help them become dominant.
Grasping fingers
and forward-facing eyes.
Over millions of years,
they survived and later thrived on Earth.
This led to primates diversifying
and the emergence of different species.
Which then gave us two main groups.
The primates
who would later evolve into monkeys and apes.
And the hominids,
who would later evolve into humans.
But this won’t happen for millions of years.
As the Cenozoic era progressed,
hominids learned how to use tools,
control fire,
and develop the beginnings of early language.
As more and more hominids appeared,
they spread globally
and could be found in Asia, Europe,
Africa, and North America.
Some of these species died out.
Specifically the Neanderthal.
They evolved outside of Africa
and adapted to live life in Eurasia.
But as modern humans progressed,
they were more technologically advanced,
eventually leading to the extinction
of the Neanderthal.
As more and more species
of hominids evolved,
more and more died out.
The only ones to survive were
the homo sapiens
who stayed in Africa.
Their brains continued to grow,
leading to more advanced language,
technology, culture,
and eventually you.
Speaking of you,
how would you survive in this era?
Well, to do that,
it'd be helpful to know what the Cenozoic era
was made up of.
After all,
it spanned tens of millions of years.
And a lot of stuff happened.
The Cenozoic era is divided
into three time periods.
The paleogene,
neogene and the quaternary period.
Let's quickly break them down.
This marked the start of the Cenozoic era.
The mammals we've been talking about,
along with flowering plants,
have begun to emerge.
Oh, and watch out for some creepy-looking insects.
Earth’s tectonic plates
continued to shape continents,
as they have been for many millions of years.
South America and Africa
would continue to move apart.
And the Himalayas
would begin to form.
You'd notice a generally warm
and comfortable climate,
but that would start to change
as you move into the next era.
Ok, the hominids we were talking about
have now appeared,
and more modern plants
and animals have begun to evolve.
One of the main things you'll notice
is how much colder it's getting.
Ice ages are becoming
more common during this period.
This period had multiple ice ages
and interglacial moments.
The Earth cooled down
and heated up several times.
Humans, along with the large mammals
we mentioned earlier,
had more impact than ever before.
This period is also known
as the Anthropocene,
which recognizes the significant impact
humans had on Earth's ecosystem
and geology.
So, how would you survive
during these times?
Well, it would be much easier
than if you were to live in a time period even further away.
Hundreds of millions of years ago,
Earth had more oxygen,
which would make breathing more difficult.
But luckily you don't need to worry about that.
You just have to be wary
of the giant animals trying to kill you,
the unpredictable weather,
and the weird kinds of foods
that could make you sick.
Sounds easy, right?
Hopefully, you'll be able to cozy up
with some early hominids
and join their tribe.
They'll have access
to shelter, fire, and tools.
And if you can't manage to do that,
well, find a cave,
make a fire, and hope for the best.
But wait - you're technically surviving
in the Cenozoic era right now.
Yeah, that's right,
this era hasn't ended yet.
We’re currently living
in the quaternary period.
Era's on Earth
are typically marked by major geological shifts
or mass extinctions.
Neither of which we've had to deal with, luckily.
But what if we did?
What if humanity suddenly went extinct?
Would it mark the start of a new era?
Well, that sounds like a story
for another WHAT IF.
Hey, don't click off
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