>>NANCY SIMMONS (Curator, Division of Vertebrate Zoology): The primary way that you find your
fossils is you go out and you just walk slowly over exposed areas of rock and sand, looking
for pieces of bone.
You’re looking, looking, looking.
Oh, here’s a piece of bone.
Maybe I can find some other pieces of bone nearby.
That’s the standard way in which we find fossils all over the world.
Microfossils are different because they’re so small that you can’t see them easily.
It just looks like a tiny rock, a grain of sand.
And so to find microfossils we need to use different techniques than are typically used
to look for all other fossils.
>>SIMMONS: We are at La Venta in the river valley of the Magdalena River in central Columbia.
I’ve known about La Venta fossils for 30 years, because some of the bat fossils are
the most important records of early bat evolution in the new world.
I’m a paleontologist originally by training, although most of my recent research over the
last 25 years has been focused on modern bats.
La Venta gives us a picture of what the South American bat fauna looked like between 10
and 14 million years ago.
And there’s no other place that’s even remotely like this in terms of its ability
to show us what that slice of time looked like.
>>ANDRES LINK (Assistant Professor, Universidad de los Andes): 13 million years ago, La Venta
was a very different place.
I imagine it full of wetlands.
Lots of turtles, lots of crocodiles, fish.
>>SIOBHAN COOKE (Assistant Professor, Johns Hopkins University): Hoofed animals that would
have grazed on the tropical vegetation that would have been quite lush.
Tropical forest animals, like monkeys and bats.
There are I think about a 130 vertebrate species that have been described here.
>>SIMMONS: Since that time, the rise of the Andes has caused changes
in local weather patterns.
This region is basically a tropical desert today.
>>LINK: The fossil deposits of La Venta have been very influential, in terms of the diversity
of fossils that it has provided.
And also because it’s a place that has provided at least 13 species of bats, all known from
very fragmentary material, a couple of teeth–basically because they are tiny animals, no?
>>SIMMONS: To find those little teeny-weeny fossils of bats and other micromammals, we
can’t just look around on the ground for them, because they’re too small to see.
They’re not any bigger than a grain of rice or a piece of sand.
So what we do is we collect shovelfuls of sandy rock from places that seem to be promising,
that we think probably have tiny fossils mixed in them.
And then we put them into screens with water and we basically wash it all down.
So we try to get all the clay and the soil out so that we’re left with just little
bits of rock and little bits of fossil.
Not very much screen washing has been done in La Venta previously, and it was the screen
washing that was done in the past that turned up the bat fossils.
So this Niarchos expedition, the central plan is to go to a number of sites around the area
and screen wash it ourselves, in hopes that we’ll have a whole new picture of the micromammal
fauna that’s out here in this region.
>>COOKE: We’ve been here for about a week now, and it is a team of researchers and students
who are specialists in different organisms that were present at the site.
Having all the students serves a training function, too, so that the students can learn
paleontology, can learn a little bit more about La Venta and what life was like in northern
South America during the Miocene.
>>SIMMONS: The local community in this region have always known about the fossils.
And kids grow up out here going out and finding fossils.
And some of our most important collaborators here are local people who are extremely good
field paleontologists.
>>ANDRES FELIPE VANEGAS (Director, Museo de Historia Natural La Tatacoa): This initiative came about
as a dream of a group of children who were curious about fossils,
and we delved into paleontology without knowing it.
[La Venta and] the Tatacoa Desert are recognized worldwide for its great importance in paleontology,
but unfortunately the older investigations stalled.
With this work we have managed to reawaken the interest of researchers to return here,
to the Tatacoa Desert.
>>LINK: It’s been a great synergy, because they are not only experts on where the fossils
are but also they have been very interested in the science behind the reconstruction of
the paleoecology and the diversity of animals that lived here 13 million years ago.
>>SIMMONS: The fossils that we’re collecting on this Niarchos expedition will be going
to one of the local museums here, and that museum will then care for them in perpetuity.
There are over 1,450 living species of bats.
In South America, which has the highest bat diversity anywhere on the planet, you can
be in a single rain forest, and there could be maybe even as many as 150 species of bats,
all living in that same piece of forest around you.
As a bat biologist, what I really want to know is, how did this diversity evolve?
How did we get to the modern fauna that we have?
The fossils that were discovered previously in this area are like little hints of what
might be here.
We believe there are many more here to be discovered.