N. Simmons/© AMNH
N. Simmons/© AMNH
N. Simmons/© AMNH Join Nancy Simmons, curator-in-charge of the Museum’s Department of Mammalogy, as she discusses her 2022 Constantine S. Niarchos Expedition to La Venta, a fossil-rich site in the Magdalena River Valley of central Colombia. This area was once a lush tropical forest but is now a tropical desert rich in fossils. Simmons will discuss the unique methods of paleontology required for finding microfossils as well as what we can learn from them, from piecing together a new picture of what the local fauna looked like in the past to understanding how bats evolved their incredible diversity today.
[MUSIC]
[The video opens on undulating badland dunes, where paleontologists are walking amongst the dunes.]
NANCY SIMMONS (Curator, Division of Vertebrate Zoology): The primary way that you find your fossils is you go out and you just walk slowly
[A person in a bright red shirt and a hat, seen from far away, investigates something on the ground in between the crests of rock.]
SIMMONS: -over exposed areas of rock and sand, looking for pieces of bone.
[Seen from nearby, and from different angles flashing rapidly, the same person in a red shirt looks high and low for something in the sand among the ridges.]
SIMMONS: You’re looking, looking, looking.
[The person stops and looks at some small flat pieces of rock, and the camera focuses on the rocks.]
SIMMONS: Oh, here’s a piece of bone.
[The person in a red shirt is joined by another person, and they both pick up small pieces of rock and inspect them.]
SIMMONS: Maybe I can find some other pieces of bone nearby.
[The person holds up two small fossil bones to the camera.]
SIMMONS: That’s the standard way in which we find fossils all over the world.
[A person’s hands fumble with a tiny fossil between their fingers, nearly dropping it and picking it back up again.]
SIMMONS: Microfossils are different because they’re so small
[Another person nudges a small microfossil around their palm with their pointer finger.]
SIMMONS: that you can’t see them easily. It just looks like a tiny rock, a grain of sand.
NANCY SIMMONS appears on screen, speaking to the camera.
SIMMONS: And so to find microfossils we need to use different techniques than are typically used
[Scientists crouch over a thin layer of what looks like sand, picking up individual grains with their fingers and looking at them.]
SIMMONS: to look for all other fossils.
[The logo for the American Museum of Natural History appears. A title appears: “Searching for Bat Microfossils in Colombia. Constantine S. Niarchos Expedition.” As the title disappears, the scene flies slowly through rows of cacti and then over the short ridges of the badlands. A map of northern South America draws on atop that footage. The country of Colombia is highlighted in blue and labeled with text. ]
SIMMONS: We are at La Venta in the river valley
[The city of Bogotá is highlighted in the center of the map of Colombia. To the southwest of Bogotá, a star appears with text next to it reading “La Venta.”]
SIMMONS: -of the Magdalena River in central Columbia.
[SIMMONS appears on screen, with the badlands landscape behind her.]
SIMMONS: I’ve known about La Venta fossils for 30 years,
[Text appears: “Nancy Simmons, curator, Division of Vertebrate Zoology”]
SIMMONS: because some of the bat fossils are the most important records of early bat evolution in the new world.
[SIMMONS stands with another scientist, at night in a rainforest elsewhere. Both people have headlamps on, and are looking at a living bat they hold in thick gloves, illuminated by their headlamps.]
SIMMONS: I’m a paleontologist originally by training, although most of my recent research-
[SIMMONS sits at a table and investigates the wings and back of a small bat, gently stretching it’s wing with her fingers.]
SIMMONS: -over the last 25 years has been focused on modern bats.
[SIMMONS digs at the earth with the blade of a pocket knife, a look of concentration on her face. The camera shifts its focus to a young researcher beside her, looking at what SIMMONS is digging up with her knife.]
SIMMONS: La Venta gives us a picture of what the South American bat fauna looked like between 10 and 14 million years ago.
[The scene flies over the badlands landscape again, where far below, scientists are walking among the ridges.]
SIMMONS: 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.
[ANDRÉS LINK appears, speaking to the camera, with a ranch house in the desert behind him. Text appears on screen: “Andrés Link, Assistant Professor, Universidad de los Andes”]
ANDRÉS LINK (Assistant Professor, Universidad de los Andes): 13 million years ago, La Venta was a very different place.
[The scene shifts to flying over a tropical rainforest with water and swampland between its trees.]
LINK: I imagine it full of wetlands.
[A mostly-submerged crocodile floats in the water.]
LINK: Lots of turtles, lots of crocodiles, fish.
[A tapir walks quietly through a lush rainforest understory, sniffing the air with its snout.]
SIOBHÁN COOKE (Assistant Professor, Johns Hopkins University): Hoofed animals that would have grazed on the tropical vegetation that would have been quite lush at that time.
[A howler monkey sitting in the tree branches opens its mouth to howl. A bat hanging upside down bares its teeth.]
COOKE: Tropical forest animals, like monkeys and bats.
[COOKE appears on screen, talking to camera. Behind her is the badlands landscape. Text appears: “Siobhán B. Cooke, assistant professor, Johns Hopkins University.”]
COOKE: There are I think about a 130 vertebrate species that have been described here.
[The scene flies over the badlands landscape again, showing buttes and ridges with little to no vegetation, just a rocky landscape.]
SIMMONS: Since that time, the rise of the Andes has caused changes in local weather patterns. This region is basically a tropical desert today.
[The camera looks closely at some large fossil teeth in a person’s hand. They each look like an icepick or railroad tie: blunt and long. LINK and another researcher dig rhythmically at a sandy pit with rock hammers.]
LINK: The fossil deposits of La Venta have been very influential,
[We see LINK’s face closer, concentrating on his digging.]
LINK: in terms of the diversity of fossils that it has provided.
[LINK reappears on screen speaking to camera.]
LINK: 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 reappears on screen speaking to camera.]
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.
[Two paleontologists put shovelfuls of sand from the ground into white sacks.]
SIMMONS: So what we do is we collect shovelfuls of sandy rock
[Scientists take these heavy sacks of sand and place them in the bed of a pickup truck with heavy [THUDS].]
SIMMONS: -from places that seem to be promising, that we think probably have tiny fossils mixed in them.
[Sand from the bags is dumped into a blue bucket, as a hose streams water into the bucket.]
SIMMONS: And then we put them into screens
[A hand mixes around the muddy water in slow motion.]
SIMMONS: with water and we basically wash it all down.
[Hands spray water with high velocity from a hose into a screen with wood-framed sides filled with sandy bits.]
SIMMONS: So we try to get all the clay and the soil out
[A close-up of the small bits in the bottom of the screen frame.]
SIMMONS: -so that we’re left with just little bits of rock and little bits of fossil.
[Scientists crouch around a black sheet of plastic where the sand-like pebbles and fossils are drying, and pick up individual grains, investigating them for signs of fossils.]
[SIMMONS reappears on screen.]
SIMMONS: 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.
[LINK drives a car over bumpy terrain, as we look over his shoulder at the landscape.]
SIMMONS: So this Niarchos expedition,
[A fine brush brushes away sand near a small chunk of fossil on the ground. A hand comes down to pick it up.]
SIMMONS: the central plan is to go to a number of sites around the area-
[Hands pass a bubbling hose over a screen with tiny bits of rock and sand and fossil in the bottom of it in slow motion.]
SIMMONS: -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.
[Hands pick up tiny bits of fossil from a table with lots of small pieces on it. Other hands close the cover of a book, the spine of which reads “Vertebrate Paleontology in the Neotropics.”]
[COOKE reappears on screen.]
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
[SIMMONS, COOKE, and LINK gather around a table at night with headlamps on, looking at a laptop screen and passing a small fossil between them.]
COOKE: that were present at the site.
[SIMMONS sits at a picnic table with other scientists, looking at specimens on the table. A scientist looks through a glass loupe at something in their hand.]
COOKE: Having all the students serves a training function, too,
[A student asks something of COOKE, sitting next to her, and COOKE turns to look at her laptop. A scientist writes a specimen label at the table.]
COOKE: so that the students can learn paleontology,
[COOKE and other scientists churn the sand and mud in a large blue bucket filled with water.]
COOKE: can learn a little bit more about La Venta
[Two students point at something on the other side of the glass in a museum, a fossil of a mammal that used to live in La Venta.]
COOKE: and what life was like in northern South America during the Miocene.
[Students and scientist gather around a large, partially-restored fossil turtle shell, while a museum worker explains it to them. He compares it to a smaller fossil turtle shell.]
SIMMONS: The local community in this region have always known about the fossils. And kids grow up out here going out and finding fossils.
[SIMMONS reappears on screen.]
SIMMONS: And some of our most important collaborators here are local people who are extremely good field paleontologists.
[A local Colombian scientist shovels sand into a white sack.]
ANDRES FELIPE VANEGAS (Director, Museo de Historia Natural La Tatacoa): [translated from Spanish] This initiative came about,
[VANEGAS appears on screen, speaking to camera. Behind him is a laboratory for preparing fossils. Text appears: “Andres Felipe Vanegas, Director, Museo de Historia Natural La Tatacoa.”]
VANEGAS: -as a dream of a group of children who were curious about fossils and we delved into paleontology without knowing it.
[Close-ups of things around the paleontological laboratory: rows of fossil skulls and an almost complete fossil mammal; another fossil mammal skull.]
VANEGAS: [La Venta and] the Tatacoa Desert are recognized worldwide for its great importance in paleontology,
[VANEGAS reappears on screen, speaking to the camera.]
VANEGAS: but unfortunately the older investigations stalled. With this work we have managed to reawaken the interest of researchers
[A museum worker shows the interior of a fossil turtle shell to a scientist, who nods.]
VANEGAS: to return here, to the Tatacoa Desert.
[LINK reappears on screen, speaking to the camera.]
LINK: It’s been a great synergy, because they are not only experts-
[A Colombian scientist hands a fossil to an American scientist as they look for fossils in the badlands.]
LINK: -on where the fossils are but also they have been very interested in-
[Close-up shots of the microscope in the fossil preparation laboratory inside the previous museum.]
LINK: -the science behind the reconstruction-
[LINK reappears on screen, speaking to the camera.]
LINK: of the paleoecology and the diversity of animals that lived here 13 million years ago.
[A close-up of hands holding a small fossil bone and turning it over. Another set of hands holds a different fossil bone, and hands it over to someone else.]
SIMMONS: The fossils that we’re collecting on this Niarchos expedition
[A sign for the Museo de Historia Natural La Tatacoa hangs high above some trees lining a street. We see the front entrance of the museum as some cyclists pass by.]
SIMMONS: will be going to one of the local museums here,
[On display in the museum, we see a wall of many small bones, and close ups of some teeth. We then see a fossil skull in a display case.]
SIMMONS: and that museum will then care for them in perpetuity.
[Through a magnifying glass in the fossil preparation lab, we see another fossil skull. SIMMONS reappears on screen, speaking to the camera.]
SIMMONS: There are over 1,450 living species of bats. In South America, which has the highest bat diversity anywhere on the planet,
[Small bats hang upside down inside the tented underside of a large leaf, peering at us.]
SIMMONS: you can be in a single rain forest,
[Several bats hang upside down in a damp cave, jostling each other and some flying off.]
SIMMONS: and there could be maybe even as many as
[Over the treetops of the rainforest, two bats swoop and soar in aerial hunting maneuvers.]
SIMMONS: 150 species of bats, all living in
[Thousands of bats fly in a stream-like formation against a dusky sky.]
SIMMONS: that same piece of forest around you.
[SIMMONS churns mud in a large blue bucket.]
SIMMONS: As a bat biologist, what I really want to know is,
[SIMMONS peers through a loupe at an unseen tiny fossil in her hand.
how did this diversity evolve?]
[SIMMONS stands in the collections space of the American Museum of Natural history, and pulls out a drawer of prepared bat specimens of different shapes and sizes, all with bright red tags.]
SIMMONS: How did we get to the modern fauna that we have?
[SIMMONS reappears on screen, speaking to the camera.]
SIMMONS: The fossils that were discovered previously in this area are like little hints of what might be here.
[Hands rotate what looks like a small row of fossil molars, set into a jaw. Fingers hold up a tiny fossil vertebrae.]
SIMMONS: We believe there are many more here to be discovered.
[Credits roll.]
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