Squeaks and I love it when the weather gets warm!
We get to have picnics, go to the beach, and spend all day exploring!
But you know, the Earth didn't always get this warm every year.
It goes through some warmer periods and some colder ones.
A very long time ago, the world went through what's called an ice age.
It was so cold that a lot of the Earth's water stayed frozen as ice for most of the year.
Most of that ice went away about 12,000 years ago, way before your parents or grandparents were born.
But before that, when so much of the world was covered in ice, life looked a little different!
A lot of the same kinds of animals we have today were around then, too.
Yes, including rats, Squeaks! But!
There were also some animals back then that have since died out,
animals that were much bigger than we're used to.
If you were to take an ice age tour around the world, you'd meet some pretty wacky characters!
Imagine meeting a glyptodon, a relative of the armadillo.
That's right, we've learned about armadillos before!
They're covered in armor to keep them safe from other animals.
The glyptodon looked a lot like an armadillo, and it also had armor, but it was the size of a car!
Some glyptodons even had sharp spikes on their tails.
There were also giant beavers, which could grow to two and a half meters long and weigh 100 kilograms.
Imagine a cute little beaver, but grown to the size of a bear!
And there were mastodons and mammoths, both relatives of today's elephants.
They're all part of the group of animals that have a trunk for a nose.
Mastodons and mammoths had a lot in common:
they were both enormous, had long, shaggy hair that kept them warm,
and had trunks to help them scrape snow and ice off the plants they wanted to eat.
But there were also some differences between them.
For example, mastodons had long, pointed tusks, whereas mammoths had curvy ones.
And mastodons had cone-shaped teeth to crush the plants they ate,
but mammoth teeth looked more like crinkly potato chips, with ridges to help them grind up grass.
But you don't have to worry about running into any of these animals on your way to school.
By about 10,000 years ago, they had all gone extinct, meaning they weren't around anymore.
And even if you did run into a mastodon or glyptodon, you wouldn't have to worry.
Everyone we just met was a herbivore, which means they ate plants, not other animals.
But some giant animals from the ice age did eat other animals.
Smilodon was a big cat that lived in North and South America.
People sometimes call it a saber-toothed tiger, even though it isn't really a close relative of tigers.
But I bet you can guess where the name "saber-tooth" comes from.
Smilodon had two giant teeth that were long and curved, almost like a type of sword called a saber.
And smilodons were predators, which means they hunted and ate other animals.
They probably used their giant saber teeth to hunt the other huge animals that lived around the same time,
like mastodons and mammoths.
Then after hunting down their lunch, they had to eat it!
To bite around those giant saber teeth, they were able to open their mouths really wide.
Smilodons also had a tongue bone, a lot like today's lion.
Which probably meant they could roar like lion.
Just like the animals it ate, the smilodon is extinct.
All these huge ice age animals stopped existing by around 10,000 years ago,
and scientists are still trying to figure out why.
Some scientists think that humans could have hunted them to extinction, especially mammoths and mastodons.
That could be part of why, but there are probably other reasons, too.
Some other scientists think that when the Earth warmed up again
and there was less cold ice and more wet forest,
it was harder for these gigantic animals to find enough of the food they usually ate.
It could also have been a combination of both!
Ice age animals might have already been having trouble by the time humans started hunting them more.
Even if a mastodon was able to find a new place to go after all its favorite plants were gone,
once it had to worry about human hunters, too, it might not have been able to survive.
So, these giant animals are gone now.
But we can learn all about them by studying the bones they left behind,
and imagine what it was like to live in a world with car-sized armadillos
huge hairy mastodons, and giant-toothed smilodons!
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