{"id":3561,"date":"2026-04-07T11:00:00","date_gmt":"2026-04-07T11:00:00","guid":{"rendered":"https:\/\/rjbarrett.redirectme.net\/?p=3561"},"modified":"2026-04-07T11:00:00","modified_gmt":"2026-04-07T11:00:00","slug":"the-la-brea-tar-pits-have-been-sucking-in-visitors-for-millennia-paleontologists-are-still-finding-out-what-lies-within-the-ooze","status":"publish","type":"post","link":"https:\/\/rjbarrett.redirectme.net\/?p=3561","title":{"rendered":"The La Brea Tar Pits Have Been Sucking in Visitors for Millennia. Paleontologists Are Still Finding Out What Lies Within the Ooze"},"content":{"rendered":"<p><br \/>\n<\/p>\n<div data-article-body=\"\">\n<header class=\"article-header\">\n<h2 class=\"tagline article-tagline\" itemprop=\"description\">In Los Angeles, scientists are delighted to decode one of the richest fossil records on Earth<\/h2>\n<div class=\"article-line\">\n<section class=\"author-box by-line\">\n<div class=\"author-text\">\n<p class=\"author\" itemprop=\"author\">\n<p>          By<\/p>\n<p>          Richard Conniff<\/p>\n<p class=\"photographer\" itemprop=\"photographer\">\n<p>          Photographs by Michael Christopher Brown<\/p>\n<p>      <time class=\"pub-date\" itemprop=\"datePublished\" data-pubdate=\"April 7, 2026, 7 a.m.\">April\/May 2026<\/time><\/p><\/div>\n<\/section><\/div>\n<\/header>\n<figure class=\"article-image lead-article-image\">\n            <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/3gxpNztMdQ8qJQFc9AQLGh6opO4=\/1000x750\/filters:no_upscale():focal(954x641:955x642)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/1d\/f0\/1df02fdc-736f-409e-abb8-c82d02ff5c95\/mcb1480_copy.jpg\" alt=\"La Brea Tar Pits Opener\" itemprop=\"image\"\/><figcaption class=\"caption\">\n<p>                A visitor gazes at a statue of a giant short-faced bear. At around 11 feet tall, the Ice Age animal was the largest carnivorous mammal ever to roam North America.<br \/>\n              <span class=\"credit\">Michael Christopher Brown<\/span><br \/>\n            <\/figcaption><\/figure>\n<p>Unusually\u00a0for a major tourist attraction, the phrase \u201cdeath\u00a0trap\u201d features prominently in the signage and the lore at the La Brea Tar Pits, the celebrated fossil site\u00a0in the heart of Los Angeles. \u201cDeath Trap for Meat-Eaters\u201d says the sign at one site, though in truth it\u2019s a death trap for plant-eaters, too. Over the past 60,000 years or so, animals by the millions, including giant ground sloths, saber-toothed cats, dire wolves and ten-ton Columbian mammoths were stuck in the goo and died here\u2014and were quickly preserved in exquisite detail by the same stuff that killed them.<\/p>\n<p>For scientists, the La Brea death trap matters because the animals entombed here, now mostly extinct, are remnants of a lost North America. Not so long ago, big, scary animals, both predator and prey, dominated the landscape, much as they still do in parts of Africa today. Their abrupt disappearance roughly 13,000 years ago makes La Brea a tantalizing window into the American past, what the International Union of Geological Sciences calls \u201cone of the most important fossil localities in the world.\u201d Emily Lindsey, a La Brea paleoecologist with a passion for the strangeness of giant ground sloths, goes further: \u201cThere is almost nothing on Earth of any time period that can match the number of fossils and the diversity of fossils.\u201d<\/p>\n<p>This range includes megafauna and microfossils, plants, insects, snails, even fungi, all preserved together. Lindsey and Regan Dunn, a former river guide and ski instructor turned paleobotanist, are the scientific leads at La Brea. The big question researchers hope these fossils can answer is why such a world suddenly disappeared when it did\u2014and what, if anything, those findings can tell us about our own world.\u00a0<\/p>\n<p>For nonscientists, though, La Brea\u2019s \u201cdeath trap\u201d image has a different appeal. \u201cLots of screenwriters live in the area,\u201d says Dunn. Her eyes widen but do not quite roll. \u201cYou sometimes see them around with their laptops.\u201d\u00a0<\/p>\n<p>Act I, Scene 1 often takes place at the sizable \u201cLake Pit\u201d by La Brea\u2019s front gate, just off Wilshire Boulevard. The location is production friendly, just 15\u00a0minutes from major Hollywood studios, and suitably apocalyptic, with methane bubbling ominously from the surface and a statue of a desperate mammoth mired hip-deep in tarry liquid. In the recent NBC television series \u201cLa Brea,\u201d a sinkhole opens here and drops attractive people into a primeval underworld. And in the 1988 movie <em>Miracle Mile<\/em>, a boy-meets-girl, boy-loses-girl, boy-finds-girl story, the happy couple are racing away from a nuclear apocalypse when their helicopter suddenly spins down into the tar. As the goo rises around them, they console themselves with the thought that their fossilized\u00a0remains might someday be displayed in a museum.\u00a0<\/p>\n<div class=\"insight\">\n<div>\n<p class=\"h4-style\">Did you know? The secrets of La Brea<\/p>\n<ul>&#13;<\/p>\n<li>No dinosaur fossils have been found at La Brea because the area was underwater at the time they roamed the Earth.\u00a0<\/li>\n<p>&#13;<\/p>\n<li>The Chumash people used the area\u2019s asphalt for waterproofing baskets and sealing canoes, long before the first Europeans arrived.\u00a0<\/li>\n<p>&#13;\n<\/ul>\n<\/p><\/div>\n<\/div>\n<figure class=\"article-image left\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/00yaKfSM7XnNUS8ZO93zw5hMaZg=\/fit-in\/1072x0\/filters:focal(1000x1506:1001x1507)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/d8\/6b\/d86bd7b8-5f4c-4e47-ab57-9b784d8528a2\/mcb9467_copy.jpg\" alt=\"Dire wolf skulls\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      A wall at La Brea shows off its wealth of dire wolf skulls.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>Such depictions may be Hollywood kitsch, but they live in the hearts of fans. \u201cThis is right where the movie <em>Volcano <\/em>happened, right?\u201d exclaims a middle-aged man in a cowboy hat to two pals one morning as they stride past the tar pit, bound for the George C. Page Museum on the La Brea grounds. In that 1997 movie, La Brea gives rise to a volcano, which flings flaming \u201clava bombs\u201d and sends a river of molten rock flowing through the city. Perhaps as a nod to the site\u2019s morbid reputation, the man in the cowboy hat has dressed for his La Brea visit in a black T-shirt printed with lyrics from the heavy metal group Venom: \u201cWe suck the blood of the beast and hold the key to death\u2019s door.\u201d\u00a0<\/p>\n<hr\/>\n<p>For visitors, the first clue that there\u2019s something different about the land around the museum is in the bare patches among the trees, where the exposed earth is a little too dark and dead leaves are stuck in place. On one such patch, a stray soccer ball waits like an invitation to come closer. Don\u2019t. In fact, there are fences to keep you away.<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/3lTncMatxAwfPWrxOIdxN2Kdxso=\/fit-in\/1072x0\/filters:focal(954x645:955x646)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/d7\/27\/d727dd32-4b0e-405f-b1aa-cef62b0f0d2d\/mcb0079_copy.jpg\" alt=\"Emily Lindsey\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      Paleoecologist Emily Lindsey raises up the skull of an extinct short-faced bear and compares it with a grizzly skull from the current epoch.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>These dark patches have always been the real hazard, not the lake out front. Lindsey, who is the excavation site director, dismisses the lake as a\u00a0giant hole in the ground left behind by commercial mining in the late 19th\u00a0century. The almost ordinary\u00a0patches of ground are more deadly for being less obvious. What they hide beneath the leaves is not a lake, or even a pit, but a shallow seep. The dirt is saturated with asphalt, the lowest grade of crude oil. Long before commercial mining, Native Americans harvested the asphalt here to waterproof baskets and boats. Early Spanish colonists likewise used the asphalt to seal their roofs. They were the ones who named the place \u201cLa Brea,\u201d which means \u201cthe tar.\u201d<\/p>\n<p>The oil pushes up through narrow cracks in the rock from oil deposits between 500 and 1,000 feet underground. The asphalt didn\u2019t pull its victims down into the earth, as Hollywood likes to suggest. Even a shallow puddle was enough to lock creatures in its adhesive grip, where they died of exposure or starvation, or were finished off by predators that then often got trapped themselves. As did many scavengers following behind. Inside the\u00a0museum, schoolchildren and parents flock to an exhibit that invites them to pull up on the handle of a shaft stuck in tar and see what being trapped might have been like. These encounters suggest that most of these people would have gone the way of the perished mammoths.<\/p>\n<p>There are however other, quieter ways to approach La Brea. The museum is part of Hancock Park, a 23-acre refuge from the traffic and chaos of central Los Angeles. Parents wander with a child or two down winding paths shaded by live oak trees. School groups picnic under date palms. An exercise class works through its routine at the foot of a slope. Visitors can amble in through the museum\u2019s back gates and visit Project 23, a fenced-in area where a paleontological excavation is in progress.\u00a0<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/Nafzoz9MSp2tA4egR-vxSPLeWQA=\/fit-in\/1072x0\/filters:focal(954x641:955x642)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/17\/31\/17316255-6799-4ae8-95d2-957aa17a9f79\/mcb8862_copy.jpg\" alt=\"The La Brea campus\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      The La Brea campus on L.A.\u2019s Wilshire Boulevard. Some residences in the surrounding affluent area need regular pumping to clear rising asphalt.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>The crates in Project 23 came to the museum from the Los Angeles County Museum of Art, which began building an underground parking lot next door in 2006 and excavated 16 pockets, loading the contents into 23\u00a0crates. The largest weighed 123,000\u00a0pounds.\u00a0<\/p>\n<p>Now a wooden crate stands open, revealing what looks like a crude sculpture roughly five feet tall. It\u2019s a tableau of death, a cataclysmic mix of blackened ankles, teeth, femurs and skulls jammed together. This mass grave was carefully excavated and set aside during construction at the site. The bones in the crates are still embedded in asphalt, just as they were underground. Before removing them from the crates, Sean Campbell, a paleontological preparator at the museum, uses a laser to measure each one and carefully documents its position relative to the others.\u00a0<\/p>\n<p>Next, Campbell goes to work excavating a large rib, spraying on solvent to soften the asphalt that holds it in place. The asphalt yields to gentle scraping with dental tools and accumulates in glistening little heaps like couscous cooked in motor oil. \u201cSo far,\u201d Campbell says, as he works, \u201cI have a baby ground sloth, a baby bison, a baby horse.\u201d\u00a0<\/p>\n<div class=\"binding-box\">\n<div class=\"embedly-retail\">\n<div class=\"column\">\n<p>        <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/Y3tJhVujnebgcJHmfJ2ZuXSN2Wo=\/fit-in\/300x399\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/94\/3a\/943ad83b-0672-4a32-8e4f-b559deee125b\/aprmay26_-_web_cover.jpg\" width=\"300\" height=\"399\" alt=\"Cover image of the Smithsonian Magazine April\/May 2026 issue\"\/><\/p><\/div>\n<\/p><\/div>\n<\/div>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/26CRtOVKrIvUjGXiJCPa4H3s5KA=\/fit-in\/1072x0\/filters:focal(732x495:733x496)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/1f\/30\/1f30b338-207d-4142-97d3-c83cb854927a\/1914_hancock_park_a_mammoth_bone_found_in_pit_9.jpg\" alt=\"1914\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      In 1914, a worker in La Brea\u2019s Pit\u00a09 crouches beside the femur of a young Columbian mammoth. Bones from 27 mammoths were excavated at La Brea that year.<\/p>\n<p>      <span class=\"credit\">Courtesy of the Natural History Museums of Los Angeles County<\/span><\/p>\n<\/figcaption><\/figure>\n<p>Visitors often pay special attention to the babies in the collection. \u201cPeople are just like, \u2018Oh, God, that\u2019s so terrible.\u2019 And I\u2019m like, \u2018Yes, but they would have died 40,000 years ago by now anyway. But at least they\u2019re now present for the scientific record, for us to study and analyze them and learn more about their lives.\u2019\u201d He continues with his roster of the dead in the crate: \u201cOne deer, a few dwarf pronghorns, tons of coyotes, at least three adult dire wolves and at least one subadult saber-\u00adtoothed cat. A partially articulated rodent &#8230;\u201d<\/p>\n<p>Time and geological upheaval below ground have left many of the bones battered, including the rib. Campbell wraps it in aluminum foil to keep it intact as he gently rocks it back and forth, out of the dirt. Then he brings it to a bench and wraps it again, this time in orthopedic casting tape. A half-hour in the sun will harden it, leaving it ready to be cleaned up and\u00a0repaired more durably at a lab inside the museum.<\/p>\n<p>What comes out of the ground here is true buried treasure. A nearly intact saber-toothed cat skull,\u00a0unearthed nearby in the 1960s, sold at auction in 2009 for $334,600. But the museum doesn\u2019t sell its discoveries. A volunteer named Lynne Schneider, retired from a career as a government contractor, has been \u201cworking for months on a dire wolf skull that\u2019s very broken up.\u201d Now, she says, she\u2019s almost getting to \u201cthe point where I can start consolidating the bone and gluing it together.\u201d Barbara Hill, another volunteer and a former aerospace worker, stands on the opposite side of the same blackened mass of bones. Both women volunteer two days a week. Hill divides her time between Project 23 and the prep lab inside the museum, though that schedule can change\u00a0depending on where she is needed most. \u201cIt feels like a custody battle,\u201d Hill jokes of her split schedule.<\/p>\n<p>At the lab, preparators stand at a long, horseshoe-\u00adshaped bench facing out into the public area. Visitors watch through plate glass windows. Jars of Q-tips, toothpicks and foam-tip makeup applicators stand at the ready for the cleaning and sorting process. Manicure sticks, the kind beauticians use for pushing back cuticles, \u201care very nice for removing stubborn matrix,\u201d says Connie Clarke, a staff preparator,\u00a0referring to the sediment that hardens around fossils. \u201cAn electric toothbrush is good for removing a clay layer.\u201d Alongside the bone consolidants and glues are degreasers for cleaning the bones. \u201cIn the old days, they used boiling kerosene,\u201d Clarke says. But boiling a flammable liquid, she adds, is \u201cnot ideal.\u201d\u00a0<\/p>\n<p>Like Schneider and Hill, the other preparators are mostly longtime volunteers\u2014an anthropologist, a veterinarian, a software developer. \u201cA fun mix,\u201d Clarke says. Today, they\u2019re working not on large, easily recognizable bones but on shallow dishes of debris scooped from a gallon paint can. It\u2019s the oily couscous that originally surrounded the bones out at Project 23, now dried and thoroughly cleaned. When the preparators view them through a microscope, items in the mix sharpen into bits of sticks, shells, bones, plants and insects. They use the bristles of a fine artist\u2019s paintbrush to nudge pieces to one side or another, sorting them by type.<\/p>\n<p>Next to the gallon can, the results of recent sortings occupy clear plastic boxes. Clarke carefully opens a box full of the glossy blackened heads of insects, some smooth, some pitted, their rounded skull-like shapes resembling the singed aftermath of a mass catastrophe. \u201cSometimes a sneeze or a deep sigh will send things rocketing away,\u201d she warns.\u00a0<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/a99gQOGFsG9lg2JV0zJS2cJxq-k=\/fit-in\/1072x0\/filters:focal(454x685:455x686)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/1c\/9f\/1c9fdd2a-8be5-4699-8965-c1c69409baef\/l1002319_copy.jpg\" alt=\"Sean Campbell\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      Sean Campbell, a paleontological preparator at La Brea, removes liquid asphalt from an excavation pit, a procedure known as \u201cglopping.\u201d<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>Dung beetle fossils have lately become Hill\u2019s specialty. A paleontologist helpfully told the volunteers that the underside of a dung beetle\u2019s head looks like a toilet seat, and so far, in a few days of microfossil sorting, Hill has found two dung beetle heads that may represent previously unknown species; she hopes to find another today. \u201cIt\u2019s treasure!\u201d Hill says playfully, giving herself a pep talk. \u201cYou\u2019re going to find it! Open a whole new page of history!\u201d<\/p>\n<hr\/>\n<p>The big animals that thrill the popular imagination may have died at La Brea only once or twice in a\u00a0decade. But across millennia, those numbers added up. In the museum\u2019s collection rooms, saber-toothed cat skulls fill a line of cabinets 8.5 feet high and 50 feet long, while drawers full of saber-toothed cat astragali (or ankle parts) and other bones are lined up like spoons. A public display wows museum\u00adgoers with 400 dire wolf skulls in almost military formation. Another 430 are stored in back for scientific research.\u00a0<\/p>\n<p>\u201cIs it real?\u201d a visitor demands, in front of a massive skeleton of a Harlan\u2019s ground sloth. It\u2019s a standard question at La Brea, and Becca Prater, an educator on staff, confirms that, yes, it\u2019s real. \u201cWe have found over 9,000 of their fossils. So we do have a fully articulated skeleton of a Harlan\u2019s ground sloth here.\u201d Then, scrupulously, she adds that those 9,000 bones probably came from about 60 individuals. Like nearly all skeletons at natural history museums, this one is a composite. The bones of individual animals rarely turn up intact, or even in the same place. \u201cSo who\u200bever had that skull never knew the guy with those ribs, and probably never was friends with the sloth that now holds his legs up. So we Frankenstein them all together, and build these big composite skeletons with the pieces we find.\u201d The viewer goes away satisfied. But the \u201cis it real?\u201d question will inevitably recur.<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/LKapVXfbRjcAHKrPIyYsE9-StCs=\/fit-in\/1072x0\/filters:focal(954x645:955x646)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/e3\/60\/e360420b-954b-4e7e-8479-c5065690ac52\/mcb7916_copy.jpg\" alt=\"bird skull\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      A preparator works on a bird skull, taking care with the bone\u2019s thin walls. The asphalt in the pit served as a natural preservative for delicate fossils.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>The challenge for La Brea, says Lindsey, is that it\u2019s \u201ca spectacle,\u00a0and it\u2019s also in the middle of the worst city to be a spectacle. People come to L.A. expecting to see made-up experiences\u201d\u2014\u00adlike Universal Studios or Disney\u2019s Holly\u00adwood Land, which bills itself as a place \u201cwhere movie moments come to life.\u201d When they come to La Brea, Lindsey says, \u201cThey\u2019re like, \u2018Oh, it\u2019s the La Brea Tar Pits Experience.\u2019\u201d It doesn\u2019t always fully register that these fossils are real, and they\u2019re still coming out of the ground in the third-largest city in North America.\u00a0<\/p>\n<p>Several seeps on the property are active enough to require fencing. Other, smaller seeps turn up from time to time, and green traffic cones labeled \u201cSticky\u201d and \u201cGooey\u201d warn pedestrians away. Workers scoop asphalt out of inconvenient areas and empty it into the Lake Pit, which is periodically pumped out by a hazmat service. There are seeps outside the museum grounds, too. Nearby homeowners who do not realize they live above an oil field sometimes call to complain: \u201cYour tar is coming up in my garage.\u201d<\/p>\n<p>Old seeps, now cut off from their source, also lie buried in pockets around the neighborhood. As preparators continue to sort through the original batch of 23 crates, construction for a new wing of the Los Angeles County art museum recently brought 37 more crates to the museum. Faced with so many specimens, some seemingly insignificant, when does a paleontologist decide to stop excavating? La Brea is planning a major redesign with a new center for Ice Age research that will emphasize lessons from microfossil research. The aim is to get it done in time for the 2028 Olympics in Los Angeles.\u00a0<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/VuhE0Qnz21Qvn4N01gVhaCvoNJo=\/fit-in\/1072x0\/filters:focal(954x645:955x646)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/59\/1c\/591c4dcf-654e-4c3c-bbd7-f299893e4ae6\/mcb9697_copy.jpg\" alt=\"volunteer\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      At Project\u00a023, Barbara Hill, a longtime La Brea volunteer, carefully excavates a delicate fossil from a dense mass of fossils encased in asphalt and sediments.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>\u00a0\u201cMicrofossils are really cool, really important,\u201d Dunn, the botanist, tells an evening audience of museum donors. \u201cThey\u2019re\u00a0super abundant if you look hard enough, and if you know how to look for them. And these small critters are really important for ecosystem function.\u201d While the monsters for which La Brea is now celebrated roamed widely across the region, size kept their smaller counterparts mostly local. \u201cWe study them to interpret what the environment was like right here at the tar pits and the surrounding area. And these small fossils tell really big stories.\u201d\u00a0<\/p>\n<p>A 2023 paper, published in the leading journal <em>Science<\/em>, shed new light on the abrupt disappearance of species including the Western horse, the American lion, a bison species,\u00a0saber-toothed cats and dire wolves. Lindsey and Dunn\u2019s collaborators at Marshall University and the University of California, Irvine, used updated techniques to remove all traces of asphalt from the fossils, which is crucial for accurate carbon dating. \u201cAnd then,\u201d says Dunn, \u201cthey said, \u2018Oh my God, we know the timing of the extinction event.\u2019\u201d\u00a0<\/p>\n<p>But what was the extinction event? Botanists like Dunn\u00a0thought that phytoliths might hold the answer. These infinitesimal stones form when plant species take up silica from groundwater and channel it into shapes that are visible only under a high-\u00adpowered microscope, and then only after grinding up stony matrix and running it through a series of acid baths and heavy liquid flotation treatments.\u00a0<\/p>\n<p>Different types of plants left behind differently shaped phytoliths. On her computer screen, Dunn points out examples: \u201cYou see kind of like a spiky golf ball at the top center? Those are palms. The one on the left, with these parallel lines? That\u2019s a fern. The one that\u2019s like a worm with spirals on it? It comes from the veins in leaves.\u201d Phytoliths are everywhere in the plant world. When you run your hand up a blade of grass and feel a spiky edge, she says, you\u2019re touching phytoliths. And they provide clues about the habitat. Certain phytoliths from the upper surface of a leaf can reveal, for instance, whether the plant lived under forest cover or in open grassland.<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/srHR096TRCav4GgJgaCzp-W-3AU=\/fit-in\/1072x0\/filters:focal(954x645:955x646)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/e2\/7c\/e27c5748-3566-4680-bcb6-0c14345a78e1\/mcb8583_copy.jpg\" alt=\"upper molars\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      Preparators work on the skull and upper molars of a Columbian mammoth skeleton that was found 80 percent intact.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>By studying fossil phytoliths, seeds, pollen and other plant remains from La Brea, the botanists constructed a timeline of what the habitat there was like in different time periods. The post-glacial pine forests of 54,000 years ago gave way to juniper and oak woodlands 30,000 years ago, and then, about 13,200 years ago, to open habitat populated by drought- and fire-adapted plants.\u00a0<\/p>\n<p>But, again, the question is why. The megafauna extinction event didn\u2019t happen only at La Brea. Ice Age fossils found scattered across the continents suggest that it was a global event. La Brea is different mainly because of the abundance and the extraordinary preservation of the evidence there.\u00a0<\/p>\n<p>Scientists worldwide have debated possible explanations for the sudden extinction. One is that at the end of the glacial period, the climate rapidly became warmer and drier, changing habitats in ways that put pressure on cold-adapted plants and wildlife. Another commonly cited explanation, the \u201coverkill theory,\u201d is based on the fact that human populations expanded around this time, including in southern California, where evidence suggests that people were present in the Channel Islands by about 13,200 years ago. These growing human populations led to heavier hunting, which intensified the pressure on large animals. A third model, put forward by Lindsey, Dunn and their colleagues in the 2023 paper, emphasizes fire: As humans traveled through this already drying landscape, they made fires wherever they went, causing conflagrations and adding to the stresses on vulnerable species.\u00a0<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/3wyzXsmW8kelsE3v1pu-gIKsABI=\/fit-in\/1072x0\/filters:focal(954x645:955x646)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/8c\/35\/8c353eaf-6a76-4ac1-b968-70bd3dc07f31\/mcb1874_copy.jpg\" alt=\"Juniper Tree\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      Associate curator Regan Dunn stands under an 18,000-year-old juniper tree.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/oyGPobcy3gyiDL3wRAA-jU3jQQA=\/fit-in\/1072x0\/filters:focal(1422x1030:1423x1031)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/35\/bd\/35bdcccc-9b89-4126-bab9-b1b6bdce83de\/1913_hancock_park_an_ancient_juniper_tree_found_in_pit_3_now_referred_to_as_the_pit_3_tree.jpg\" alt=\"The tree at the time of its excavation at La Brea in 1913\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      The tree at the time of its excavation at La Brea in 1913. Evidence found at La Brea suggests that plants of the time were struggling because of atmospheric conditions. Herbivores may have struggled as a result.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>The same asphalt that preserved bones and insect parts so well was terrible at preserving ash and charred materials. But a graduate student at UCLA named Lisa Martinez had been assembling a detailed charcoal record from the critical time period using core samples from nearby Lake Elsinore. Her results were hidden at first behind an embargo, even from Dunn. \u201cAnd then,\u201d Dunn says, \u201cwhen I was finally able to see that thesis, and I saw her charcoal record, I just nearly fell off my chair.\u201d Martinez quickly became a co-author on the paper. \u201cWhat we saw by looking at her record is that there\u2019s hardly any fire in the system\u2014until about 13,200 years ago,\u201d Dunn says. \u201cAnd I was like, \u2018Oh my God, it\u2019s humans.\u2019\u201d<\/p>\n<p>The resulting 2023 study found no evidence for the overhunting theory. Instead, the researchers proposed what they called a \u201cmore nuanced\u201d approach, a\u00a0\u201cclimate-human synergy\u201d of humans and wildlife adapting\u2014\u00adwith a wide range of results\u2014to a climate that was rapidly changing around them. During previous periods of climate change, Lindsey says, animals were able to move freely to better habitats. If ice sheets were expanding over the northern regions of what is now the U.S., the animals could move south to greener pastures. But once humans began transforming the landscape, the animals faced new barriers.<\/p>\n<p>For Lindsey, Dunn and their co-authors, these findings reveal not just what happened 13,000 years ago but also what seems to be happening now. Over the past century, they noted, southern California\u2019s climate has warmed ten times faster than it did at the time of the extinction recorded in such detail at La Brea. Frequent, prolonged droughts and wildfires are common again, as they were then. Ecosystems\u2019 failure to recover after fire suggests, they warned, \u201cthat critical thresholds for re-establishment have already been crossed.\u201d<\/p>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/BFGkVgKd0Gi7le8svC6Ha1E2yuc=\/fit-in\/1072x0\/filters:focal(954x645:955x646)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/7a\/e7\/7ae72218-9fbf-49c9-85c6-ace61d204c6e\/mcb9859_copy.jpg\" alt=\"Microfossils\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      Microfossils found at the site include a juniper branchlet, juniper seed, bird vertebra, snail shell, bird claw, skink jaw, beetle leg, beetle wing, packrat tooth.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<figure class=\"article-image center\">\n<p>    <img decoding=\"async\" src=\"https:\/\/th-thumbnailer.cdn-si-edu.com\/YA6kZZm53SbujLeTNn-hs8C37Cw=\/fit-in\/1072x0\/filters:focal(954x641:955x642)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/ad\/88\/ad88d3c8-ae66-49c4-805c-3c725e9b5119\/mcb8328_copy.jpg\" alt=\"Preparator Stephany Potze\" loading=\"lazy\"\/><figcaption class=\"caption\">\n<p>      Preparator Stephany Potze works on a bison skull at the \u201cfishbowl,\u201d where museum visitors can watch scientists clean and catalog fossils.<\/p>\n<p>      <span class=\"credit\">Michael Christopher Brown<\/span><\/p>\n<\/figcaption><\/figure>\n<p>Last year, wildfires driven by fierce Santa Ana winds raced through neighborhoods all around metropolitan Los Angeles. Over more than three weeks, the fires incinerated more than 58 square miles of habitat for humans and animals alike, destroyed more than 16,200 homes, schools and other structures, placed some 200,000 residents under evacuation orders and killed 31 people. Economists estimated the damage to the local economy at more than $250\u00a0billion. A La Brea staff member was among the locals who lost their homes.\u00a0<\/p>\n<p>Along with many other institutions, La Brea\u2019s Page Museum shut down for two days. The site itself was unharmed, and as the city gradually came back to life, it was almost possible to go on as if nothing had changed.\u00a0<\/p>\n<p>Soon after the fires\u2014let\u2019s imagine\u2014a screen\u00adwriter shows up at La Brea. She opens her laptop to a script set at the Tar Pits. Working title: \u201cDeath Trap.\u201d Heart-in-throat scenes of escape from catastrophe begin to fill the page. But then she starts to noodle around with a new plot point: What if a small band of determined researchers come out of La Brea with a story powerful enough to save our world?\u00a0<\/p>\n<div class=\"in-article-newsletter science\">\n<div class=\"leade\">\n<h3>Get the latest <strong>Science<\/strong> stories in your inbox.<\/h3>\n<\/p><\/div>\n<\/p><\/div>\n<section class=\"tag-list\">\n<nav class=\"nav-tags\">\n<\/nav>\n<\/section><\/div>\n\n","protected":false},"excerpt":{"rendered":"<p>In Los Angeles, scientists are delighted to decode one of the richest fossil records on Earth By Richard Conniff Photographs by Michael Christopher Brown April\/May [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3562,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"https:\/\/th-thumbnailer.cdn-si-edu.com\/3gxpNztMdQ8qJQFc9AQLGh6opO4=\/1000x750\/filters:no_upscale():focal(954x641:955x642)\/https:\/\/tf-cmsv2-smithsonianmag-media.s3.amazonaws.com\/filer_public\/1d\/f0\/1df02fdc-736f-409e-abb8-c82d02ff5c95\/mcb1480_copy.jpg","fifu_image_alt":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-3561","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-rj"],"_links":{"self":[{"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=\/wp\/v2\/posts\/3561","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3561"}],"version-history":[{"count":0,"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=\/wp\/v2\/posts\/3561\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=\/wp\/v2\/media\/3562"}],"wp:attachment":[{"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3561"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3561"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rjbarrett.redirectme.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3561"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}