>> There are over 35,000 museums within the United States welcoming over 850 million visitors
each year.
Did you ever wonder what goes on behind the scenes in museums?
Can you imagine the displays and exhibits we all enjoy?
Join us as we explore museums and their exhibits from the inside out.
Hi I'm Leslie Mueller, welcome to Museum Access, the show that takes you to America's
top museums to talk to the experts.
Then we go behind the scenes to learn even more, believe it or not, we're in the middle
of Los Angeles at an urban ice age excavation site.
The La Brea Tar Pits, this museum houses millions in fossils that were discovered right here.
These plants, insects and animals were trapped in sticky asphalt over 50,000 years ago.
From mammoths, tusks to mouse toes, fossils are excavated, cleaned and sorted for research
and display every day.
It's the only active ice age excavation site in an urban location in the world.
Over 3.5 million fossils have been removed from the tar pits to date, and they're still
digging.
Today we'll learn about the importance of this particular site, and learn more about
a Colombian mammoth named Zedd.
Then we'll head to Project 23 for a behind the scenes look at the amazing work that's
being done thanks to a discovery during the construction of a new underground garage.
And we'll take a behind the scenes look at the fossil labs.
So are you ready to take a scientific journey that began during the ice age?
Let's go!
So Emily, tell me about this museum.
It's unbelievable.
I've never been to one like this.
How did this all start?
Well, there aren't very many places like this.
So the La Brea Tar pits is actually one of the most important paleontological sites in
the whole world.
Paleontological?
Paleontological.
So a site with fossils.
So any fossils, lots of things can be fossils, right?
Plants can be fossils, insects can be fossils, shells can be fossils.
Here we find all of those things, and we also find the fossils of most famously the
really big mammals that used to live here during the ice age.
So saber tooth cats, and giant ground sloths, and mammoths, and mastodons, and dire wolves,
all used to live right here in L.A. and we know that because we find their bones right
here in the asphalt seeps in our park.
So let's talk about the beginning of the land itself.
So the asphalt seeps that we find here have actually been known about for thousands of
years.
We know that the indigenous tribes in California used to use the asphalt for waterproofing of
vessels, and boats, and pots, and baskets, and things like that.
But fossils were first discovered here in the late 1800s.
People had found large bones here before, but they'd always thought that it was bones
of cattle that were here on the ranch or something like that until a scientist who was traveling
through saw a bone that turned out to be the saber tooth of a saber tooth cat.
And that was when they really recognized that the history of the site went much, much deeper
and had a lot to tell science.
So the city was kind of built around it fast, fast forward because they felt that it was
usable ground still?
Well, so Los Angeles, the city developed here for a number of reasons, but one of those
reasons is oil, which is of course the reason that we have this site is because of the oil
that's underground that seeps up in certain places and creates these very sticky pools
that have trapped the plants and animals over the last 50,000 years.
So is that what a tar pit would be?
So yeah, so when we say tar pits, that's sort of a colloquial term, they're more properly
called asphalt seeps.
So the liquid that's seeping up, basically, the liquid that's seeping up here is asphalt,
which is a very low-grade crude oil, and that comes from this big oil field that's underground
that's about 1,000 feet below our feet.
And because there's a lot of earthquakes here in the Los Angeles area, sometimes these
areas of structural weakness form in the earth and these cracks open up and that oil
is able to make its way up to the surface.
And when it does, it forms these really relatively shallow pools of asphalt.
And that asphalt does two things.
So first of all, it's extremely sticky and so it's trapped thousands upon thousands of
organisms, plants, animals, big things, small things here over the years.
But also, asphalt has the quality of being able to preserve a lot of different types
of fossils.
So it's very, very unusual to find fossils of plants and bones in the same paleontological
site because the types of sediments that preserve one tend to dissolve the other.
But asphalt preserves them both.
It's also sort of unusual to find big fossils and small fossils together just because the
way that those deposits get made is very different, but the asphalt seeps collect everything.
And so what that means is that what we have here is one of the best places anywhere in
the world to look at an entire ecosystem in the past.
Well, I noticed some cones outside and it would say, I think it's like goop or something
on it.
Are those actually the seeps?
I mean, they're still coming up.
They're still coming up.
So yeah, every day, you know, people walk through the park and sometimes a new seep has
opened up in the lawn or in our parking lot or on the sidewalk across the street.
And so when we see one, we put a cone there so people know not to step there because once
you get it on your, you know, fancy shoes, it's never going to come off.
Yeah, well, tell me about some of the exhibits that we're seeing here because we're talking
about this sticky tar and I did see a couple exhibits that how are you showing people what
that's like?
Yeah.
So we have, you know, one of our most popular exhibits is actually this very simple interactive
where you can pull up on a lever basically and feel just how sticky the asphalt is and
just how hard it would be to get out of it because we don't want people, of course, like
actually going into the asphalt seeps and getting stuck because that's messy and, you
know, hard to rescue but that's a way where people can see both how sticky it is and the
difference that an animal with like small feet versus an animal with really big feet
when it fell because of course the bigger your feet are, the more surface area that
is stuck in that really sticky substance and it's just, it's really hard to believe unless
you do it.
I think.
Well, and just seeing that, the kids loved it and speaking of kids, I've seen a lot of
kids running around what kind of programs are there here, are there outreach programs
for school children or?
Yeah, we have school groups coming through all the time.
We reach a hundred thousand school kids a year.
I think, I mean, just an incredible number of students and in fact, a lot of grownups
that I talk to in L.A. when I say that I work at the Tar Peds, they remember coming here
as kids.
Oh, I know.
So it's an incredibly compelling place for kids because, you know, what child doesn't
love a saber tooth cat attacking a giant ground sloth like that.
Oh, yeah.
But it's like a diorama that moves.
Absolutely.
That's incredible.
Yeah.
But, you know, it's a really interesting place for adults to come to because the science
that we have here is so unique and so important for understanding what's going on in the world
today and a lot of the environmental crisis crises that grownups are concerned about
as well.
Things like, you know, climate change and human impacts on ecosystems and extinction.
These are all stories that are captured in the past at this site because the last fifty
thousand years, which is the time period that our fossil record covers, includes the last
major episode of global warming as we're coming out of the last ice age.
It includes the time when humans first arrived in the Americas and spread out and started
interacting with ecosystems and likely hunting certain animals and it includes the most important
extinction event of the last sixty five million years, which is when the about two thirds
of the large mammals in North America and many other continents all went extinct in
a relatively short period of time and that was during this time of overlapping climate
change and increasing human population, which is really similar to what we see happening
today.
Absolutely.
So is there research that's actually going on here other than the fossil labs?
I saw the fossil labs, but is there climate research going on too?
Absolutely.
So we have a team of scientists.
There are researchers and postdocs and graduate students working here as well as scientists
from all over the world that come throughout the year to do studies on these fossils.
Again, because this is a record that you can't get pretty much anywhere else in the world.
The ability to study the sheer variety of types of fossils and the sheer number of some fossils.
You know, this has been a mecca for people studying, say, small scale evolutionary sort
of adaptation to climate change for a long time, especially in large carnivores because
we have somewhere in the nature of five thousand dire wolves and twenty five hundred saber
tooth cats and you don't get numbers like that at what types of sites and mistakes.
I would think there would be a challenge with getting those numbers since millions have
come out.
How do you record all of them?
How do you be sure that you've got, do you have archives?
Do you record them digitally?
What do you do?
Well, so all of, we've been excavating here off and on for over a hundred years.
And so from the hundred year ago excavations, we have these huge ledger books and where
people were just handwriting in, and so we've working with both our collections team and
also a team of volunteers that absolute could not, you know, get our work done without our
amazing volunteers here that are going through now and digitizing, getting all of this information
that's in these hundred year old ledger books into an online database where we can then
easily search and say, oh, how many left legs of saber tooth cats do we have?
Yeah.
Oh my ***.
So I see this great fossil lab over my shoulder, what is that?
So this is a working research lab that we have and we actually work in there seven days
a week.
We have staff and volunteers that are cleaning the fossils that we've just brought out of
the excavations.
They're repairing them if they're broken, gluing pieces back together and doing conservation
work on them.
So we know that that fossil will be in good shape for scientists to study, not just tomorrow
or next week, but a hundred years from now.
But it's not just bones and teeth, it's plants, right?
Yeah.
So it's, you know, you can see the big things that people are working on, but there's actually
a whole section of the lab where we're looking at fossils through microscopes because we
are going through the dirt that's been collected around those fossils of saber tooth cats and
giant sloths and hidden in that dirt are the bones and remains of everything from tiny
lizards and birds all the way to the seeds of trees and the fragments and even little
bits of insects.
And so it's just a really incredible record of what Los Angeles has looked like over the
last 50,000 years that these seeps have been coming up in our park.
And it's an incredibly important story because things like mammoths and saber tooth cats
and dire wolves, as cool as they are, they had huge ranges and these are species that
lived over much of North America and often even into Central and South America.
And so they don't tell us a whole lot about what Los Angeles looked like, right?
But certain species of bushes or insects or songbirds or lizards can actually tell us
a lot about what the environment was like right here because these are species that
have really narrow environmental requirements.
And so if it's too hot or too cold or too wet or too dry, they're not going to live
in a place.
And so if we want to know exactly what Los Angeles looks like and how that changed,
how the ecosystem and the communities changed in response to climate change over the last
50,000 year period of in and out of ice ages, those are the specimens that we really have
to be looking at.
So that's a big part of the work that we do in the fossil lab as well.
Well, I saw something in the fossil lab and I've been hearing about Zed, tell me a little
bit about what was this discovery.
So we name a lot of our important discoveries.
Of course.
Zed is a mammoth.
Okay.
He was found during part of a project, a salvage excavation project called Project 23,
which was a series of incredible fossil deposits that were found when the art museum next
door to us built a parking garage about 12 years ago.
And Zed is a mammoth.
And he is the most complete mammoth we've found and a very rare instance where we found
most of the bones of a large animal that were mostly in the right position as they would
have been in life.
So that's got to be rare.
It's very rare.
It's not rare necessarily at other paleontological sites, but it's very rare here at the tarpets
because in the thousands of years that specimens are sitting in the asphalt, they seem to
get sort of disarticulated and even jumbled off of that.
Yeah.
And so you'll find individual bones of a lot of animals and maybe potentially multiple
bones of the same animal, but they're not necessarily found close to one another.
But Zed was found sort of beautifully laid out because he's actually an example of an
animal that died and was washed into a stream bed and buried before the asphalt came in.
So he didn't step in an asphalt seep and get stuck.
He actually died in more of a normal fossil sort of way, got buried.
And then later asphalt came in and helped to preserve his skeleton.
And so you can see two of his tusks on display, that are on display here, we've been working
on preparing his skull also to come out on exhibit and there are other bits of him around
the museum exhibits.
Well, I'm anxious to see this project 23, and then I think we'll step into the fossil
lab.
Absolutely.
Absolutely.
Yeah.
Let's go take a look at it.
Thanks, Emily.
Sabre tooth cats were as large as African lions, but more heavily built.
They relied on stealth rather than speed to hunt and ambush bison, camels, and ground
sloths.
Scientists are still investigating how these felines use their most memorable feature,
their four inch fangs.
These sabres may have been used for stabbing and slashing or biting open the soft underbelly
of their prey.
The American mastodon became extinct about 10,000 years ago.
They look similar to mammoths, but were separated by 25 million years of evolution and they
show key differences, especially in their teeth.
While mammoths had relatively flat teeth, which were great for grinding grass, their
main food source, the much smaller mastodon had more pointed teeth, perfect for a diet
of twigs and leaves.
I was so excited about this behind the scenes segment of this episode, because this is the
coolest area right here.
Tell me where we are.
So this is what we call Project 23.
It's our active excavation site.
We actually excavate here 361 days a year.
We're still pulling fossils out of the ground.
And why 23?
What's so special about that number?
So Project 23 is actually a big salvage excavation from when the art museum next door to us built
a big underground parking structure about 12 years ago.
And dig a giant hole next to one of the most productive fossil sites in the world.
You might expect to find some more fossils, right?
So what they found was actually 16 new, never before seen, tarpet deposits, each one full
of tens, if not hundreds of thousands of bones, and plant fossils.
The company hired a landscaping company that's used to transplanting, say, large fruit trees.
And what they did is exactly the same process they used with trees.
They pedestaled around the tarpets, built walls around each of the tarpet deposits as
they went down, cut in from underneath, built a floor, and then lifted those boxes with
an intact tarpet inside, up out of the ground, brought them over to our side of the fence.
And so each, the largest one of these weighed about 123,000 pounds.
I'm wondering if it's this one.
This is a huge one.
I mean, yeah.
Yeah, this isn't even the biggest one.
Really?
But because they did that, we're able to actually excavate these deposits exactly as
we would any other fossil deposit and take all of the same data, so we still excavate
in a grid system.
We take the really precise three dimensional measurements on all of the larger bones, and
we collect all of the dirt from around those bones that are so important for understanding
what the ecosystem looked like over the last several tens of thousands of years here in
LA.
Well, I'd love to see what it looks like inside, because I know this is a preliminary step
to actually going into the fossil lab.
So can we take a look at that?
Absolutely.
Let's go look in a tarpet.
Okay, so which crater are we looking at here, Emily?
So this is deposit 13 from Project 23, and this has been one of the most incredibly rich
deposits.
You can just see the jungle fossils that are in here.
We've got everything from really big fossils.
This is the upper arm bone of a giant ground sloth.
We've got a same bone of a saber tooth cat over there.
We've got a bunch of bird bones.
We've got ribs.
We've got sticks all tangled up.
And then among it, we have these sediments, these little gravel, public areas.
And among those, when we wash the asphalt out of, that's where we're going to find what
we call the microfossils, so the seeds and the leaf fragments, the insect bits and the
lizard jaws and mouse teeth and all of these really cool, amazing, tiny fossils that tell
us so much about what the environment was like here in LA over the past time and how
that environment changed and the species in it moved and changed in response to environmental
changes over the last 50,000 years.
Well, I'm noticing strings here, I don't know what these are for, but I want to know
what those are for, and I also want to know how do you go about attacking this?
So the strings here, these are grid lines, and these are one meter by one meter squares
that we set up, and these allow us to take really precise three dimensional measurements
on every fossil that we excavate.
And that way, when we're going and asking questions about how did this particular deposit
form, where were different fossils in relation to one another, we have all that information
at our fingertips and we can basically reconstruct the fossil deposit bone by bone.
And what kind of tools are you using to pull it apart?
You know, the main tool that we use in a deposit as dense as dense as this is actually dental
picks.
We actually get used dental picks, donated from local dentist offices, and we use not
the sharp pointy edge because we don't want to scratch the bones, but the back curvy edge
and we use that to very gently sort of grain by grain scrape away the sediments to reveal
the bones underneath.
And then to ease it out into some type of, yeah, and then once we've got all of the sediment
removed from around a fossil, we put it in a bag with all its information, and then it
goes into the fossil lab and they take it from there.
Well, I'm dying to see that too, so thanks so much, this is incredible.
[Music]
Paleontologists discovered and started excavating Pit 91 in 1915 over 100 years ago.
It was the 91st hole dug by early paleontologists.
The deposit was so rich in fossils that they still dig here every summer.
Digging at Pit 91 nearly doubled the number of species known from the tar pits.
You can watch real paleontologists excavate real fossils from the gloopy black asphalt
and learn how scientists use these specimens to study what Los Angeles was like 25,000
years ago during the Ice Age.
[Music]
This is one of our most exciting finds from Project 23.
It's Zed, our Colombian mammoth skull.
It's still in the field jacket positioned upside down.
These are where his tusks would have come out.
These are his two upper teeth, his cheekbones, and the base of his skull where it connected
to his neck.
This 40,000 year old incisor tooth, or tusk, belongs to Zed, the most complete Colombian
mammoth ever excavated at the La Brea tar pits.
A 40,000 year old tooth is pretty fragile.
When Zed was removed from the ground, his tusk and other fossilized remains were encased
in protective plaster and foam jackets like this one.
These jackets were then transported to the fossil lab where they were opened so they
could be cleaned and studied.
So this is a skull of another animal.
This is the American lion, so along with the cave lions in Europe, these were the biggest
cats that have ever lived.
They were quite enormous, and the teeth, yes, and highly carnivorous, so these were animals
that you definitely would have wanted to stay away from back in the past.
And how many of these do you have?
I see shelves and shelves of this.
Yeah, so we found probably in the nature of dozens, if not hundreds of American lions,
but nothing compared with our most famous animal, the Sabretooth cats.
We've seen a lot of museums together, right, but this complex is amazing.
To think that the unearth remains of plants, insects, and animals from the last 50,000 years
could be so relevant today, it's mind-boggling.
The La Brea tar pits continues to provide a gateway to the ice age and help us understand
the world around us.
Thanks for joining us on Museum Access, where every visit is an adventure.
I'm Leslie Mueller, see you next time.
[music]
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