Did you know that South Carolina's low country was once inhabited by giant ground sloths millions of years ago?

Matthew Gibson: <i>Typically as long as they're not feeling threatened,</i> <i>they're not much of a threat themselves.</i> <i>But I mean, it's a large animal!</i> <i>Maybe like an elephant or a bull,</i> <i>it certainly had the bulk to be able</i> <i>to take care of itself if it needed to.</i> Many examples of South Carolina's rich ecological history can be found housed inside the Charleston Museum - the oldest museum in the United States!

In its natural history exhibit, the remains of one animal in particular never fails to grab the attention of museum visitors.

Before we could take a closer look for ourselves, we needed to make the trip down to Charleston.

From our home base in Columbia, South Carolina, it's about a two hour drive to reach our destination.

This intimidating and massive looking skeleton once belonged to a mammal known as the <i>Eremotherium</i> Giant Ground Sloth.

I'm your host, Andrew Davis.

In this edition of <i>Curiosity Trek!,</i> we're going to explore the background of this creature which resided in southern North America between 5 million to 10,000 years ago!

Curator of natural history Matthew Gibson is joining us today to elucidate on the background of this ancient giant animal.

Now, generally speaking, why were animals back in those days so much larger than they are now?

So we actually see a trend when it comes to animal growth.

Over time, you'll see smaller animals evolving through time into larger forms, cutting off and then restarting.

A lot of that relates to specialization in a particular niche so as they become more adapted to that sort of role in the environment, they become more successful, meaning they can invest more of their energy into growth.

Now, as you specialize, you become dependent on whatever resources you're working with so that's why we also see mass extinctions happening.

They become so specialized that if their habitat changes even a little, you have a massive die off.

For animals to get as large as this, there has to be ample resources, and mammals, for the most part, are more comfortable in temperate, cooler environments so we can make inferences about how readily available resources were as well as just overall climate in the area.

Ground sloths in South Carolina are found in a couple of different layers, mainly because they're intermingled with other fossils.

There are a lot of erosional features that we have to deal with in the low country: hurricanes and things of that matter.

So when they intermingle them, we have to basically come up with time periods by looking at fossils from other places in North America.

Our <i>Eremotherium</i> is most likely Rancho La Brean in age because the sediment layers that do contain ice Age fossils in this area are the same animals you find in La Brean tar pits like direwolves, bison, mammoths and mastodons.

Are there other species of giant sloth around at this time?

There's a couple different ones: There's <i>Megalonyx </i>as well as <i>Mylodon</i> and <i>Paramylodon.</i> They fulfill different niches in their environment than the giant ground sloth does.

Most of them are moderately sized animals- think around the size of like an American black bear, maybe a little bit bigger.

But there were different feeding habits for those so some of them grazed, some of them exclusively ate leaves, but they didn't have the height range of the giant ground sloth so they were able to coexist.

Host: <i>In order for </i>Eremotheriums <i>to maintain their massive size</i> <i>and strength, they required a lot of food consumption!</i> <i>How did they achieve this?</i> Gibson: Well, when it comes to diet the first thing we look at is the teeth.

So giant ground sloths have high crowned teeth, meaning they ate a variety of plants, grasses, leaves, twigs, things like that.

And we can look at some of the hindquarters.

So how compressed and thick the legs are and the tail, they let us know that this thing most likely could rear up.

So it was eating things from like the tops of trees and stuff where other animals were more grazers.

So it fulfilled kind of a specialized niche; it didn't have a whole lot of competition.

And you could see with those really long limbs, it had a wide reaching range.

<i>Eremotherium</i> is thought to be somewhere around three tons.

For reference, a full grown elephant can be around seven tons.

These animals would have had to be able to move through forested environments, meaning you're going to have to push some trees out of your way.

They're just too big to walk through too crowded of areas.

So it's a good idea to just kind of think of them like solitary elephants moving through a forest.

Host: <i>The </i>Eremotherium <i>needed some hefty digits</i> <i>to properly grip and bring down</i> <i>large tree limbs.</i> <i>That's where its most distinguishing feature,</i> <i>its claws come into focus!</i> Gibson: Most likely, they were primarily used for stripping branches of their leaves.

However, there have been burrows found in South America, so we know ground sloths potentially did burrow.

Most likely not here, instead if <i>Eremotherium</i> was using them for something else, maybe digging to get to roots and things like that, just to access other plant food options.

Host: <i>Despite the </i>Eremotherium <i>being an herbivore,</i> <i>it surprisingly had very few natural</i> <i>predators.</i> Gibson: It's one of the largest herbivorous animals that would have lived in its range, so the number of predators that would have hunted this thing are probably pretty low.

But Direwolves, which are a well-known ice age mammal, would have most likely fed on young as well as older sick individuals.

But I mean, it's a large animal!

Maybe like an elephant or a bull, It certainly had the bulk to be able to take care of itself if it needed to.

Host: <i>Unlike the species of sloths found today,</i> <i>these ancient ground</i> <i>sloths were quite different</i> <i>from their present day counterparts!</i> Gibson: Ground sloths are obviously more robust.

They don't have to live that arboreal tree lifestyle, so their bones tend to be a lot thicker and bulkier.

However, the similarities some of the most easiest ones to identify are in the forelimbs: So just like our modern tree sloths, they have those really long grasping forelimbs.

Now, tree sloths use it obviously to climb, whereas ground sloths are using this to bring the plant food to them.

They also have a very similar shoulder blade.

It's something they share amongst all Xenarthrans, which is an animal group containing armadillos, giant anteaters, as well as the modern tree sloth.

I mean, they weren't fast animals for sure, but they are herbivores, so they didn't have to move very fast.

The best analog would just be like some slow herbivorous grazing animals that's kind of the speed you're looking at.

Whereas tree sloths are climbing up into areas where they're attempting to hide in camouflage.

So their low, slow metabolism is probably pretty different than our ground sloths.

Host: <i>The last of these ground sloths</i> <i>disappeared forever</i> <i>around 10,000 years ago.</i> <i>What vicissitudes led to its extinction?</i> Gibson: Toward the latter end of the Ice Age, sea levels started to rise as glaciers melt.

So most Ice Age mammals were pressured pretty heavily as their habitats were lost.

Now there are examples of <i>Eremotherium</i> and other ground sloths being hunted toward the end of their time period in South America, but we have not found any examples of that here.

Host: <i>We hope you enjoyed becoming more familiar</i> <i>with the story</i> <i>behind the Charleston Museum's</i> Eremotherium <i>sloth.</i> <i>Now that we've learned a little bit more about it,</i> <i>perhaps now you can channel your inner</i> <i>sloth and reach maximum relaxation</i> <i>if you get to see this skeleton up close!</i> I'm Andrew Davis, and we'll see you next time on <i>Curiosity Trek!.</i>