Fossils in Burmese amber offer an exquisite view of dinosaur times—and an ethical minefield

TENGCHONG, CHINA—On an overcast spring morning, a mosaic of life in the heyday of the dinosaurs takes shape piece by piece in this border city. It sprawls across hundreds of tables, on sheets spread by storefronts, and under glass counters in shops. Some vendors hawk jade or snacks, but most everyone is here for the amber: raw amber coated in gray volcanic ash; polished amber carved into smiling Buddhas; egg-size dollops of amber the color of honey, molasses, or garnet. Some browsers seek treasure for their own collections, whereas others act as virtual dealers, holding amber pieces in front of their smartphones and snapping images for distant buyers.

For scientists, this is more than a place to buy pendants or bracelets. One morning in March, paleontologist Xing Lida from the China University of Geosciences in Beijing stops at a table and examines a cockroach in a golf ball–size glob of amber, paused in time from the middle of the Cretaceous period. Its intact limbs curve off a body that looks smaller and narrower than that of today's household pests.

The dealer wants about $900. "It's an OK price," Xing says. But he moves on, hunting rarer, more scientifically valuable game.

Within a few minutes, a stranger notices Xing, shoots video of him, and posts it to social media. With 2.6 million followers on Weibo, a Chinese hybrid of Facebook and Twitter, the baby-faced, hypercharismatic Xing is a celebrity for his studies of dinosaur tracks and other adventures. Last year, he published 25 scientific papers and a dinosaur-related fantasy novel with a foreword by Liu Cixin, the country's superstar science fiction author. But Xing, like a few other Chinese paleontologists, is also lionized for the extraordinary discoveries he has made in this amber: the hatchlings of primitive birds, the feathered tail of a dinosaur, lizards, frogs, snakes, snails, a host of insects. Much as 19th century naturalists collected species from teeming rainforests in far-flung locales, these scientists are building a detailed chronicle of life in a tropical forest 100 million years ago, all from amber mined across the border in Myanmar.

"Right now we're in this frenzy, almost an orgy" of discovery, says paleontologist David Grimaldi, curator of the amber collection at the American Museum of Natural History in New York City. Hundreds of scientific papers have emerged from the amber finds, and Chinese scientists hint that many specimens have yet to be published, including birds, insect species by the thousands, and even aquatic animals such as crabs or salamanders.

But as much as Burmese amber is a scientist's dream, it's also an ethical minefield. The fossils come from conflict-ridden Kachin state in Myanmar, where scientists can't inspect the geology for clues to the fossils' age and environment. In Kachin, rival political factions compete for the profit yielded by amber and other natural resources. "These commodities are fueling the conflict," says Paul Donowitz, the Washington, D.C.–based campaign leader for Myanmar at Global Witness, a nongovernmental organization. "They are providing revenue for arms and conflict actors, and the government is launching attacks and killing people and committing human rights abuses to cut off those resources."

Much of the amber is smuggled into China in a trade that Tengchong officials and traders ballparked at between $725 million and $1 billion in 2015 alone. In China, jewelers, private collectors, and scientists like Xing exchange vast sums of cash through mobile payment apps to compete for prized specimens. The collectors often win the bidding, meaning researchers can study many specimens only on loan.

The mixture of commerce and science "raises new questions that we have not faced … in paleontology before," says Julia Clarke, a paleontologist at the University of Texas in Austin who often edits papers on Burmese amber. But given that the amber will be sold even if scientists don't buy in, she says, "What's the other prospective outcome?"

That's what drives Xing to the market. "If we don't get a specimen, it probably becomes cheap jewelry around some young girl's neck."

Exploring an ancient forest

Some 99 million years before this spring market and about 220 kilometers away in what is now Myanmar, a balmy seaside forest echoed with the calls of strange creatures. The trees bled massive quantities of resin when insects attacked them or storms broke off limbs. The resin puddled and pooled, miring countless creatures "like a mini–La Brea Tar Pits," says paleontologist Ryan McKellar at the Royal Saskatchewan Museum in Regina, Canada. Over time, the resin's frankincenselike gases evaporated; its molecules linked into polymers and hardened into what we now call amber.

Amber excels at preserving fine detail and soft tissue, says Victoria McCoy, a paleontologist at the University of Bonn in Germany. On contact, resin seeps into tissues, protecting the entombed animals and plants from fungus and rot while also drying them out. Later, the resin hardens to form a shell that further protects the fossil inclusions. In the best cases, "cellular- or even subcellular-level details are still preserved," she says.

Amber from other major deposits—specimens that wash up on beaches in Baltic countries or are mined in the Dominican Republic—is far younger. It also rarely traps strong, active creatures, such as dragonflies, or any vertebrates beyond a few lizards.

Burmese amber, in contrast, has revealed a phantasmagoria of creatures, thanks to the vast quantities coming out of the ground and the fact that single pieces regularly approach the size of cantaloupes. As Grimaldi expresses it: Imagine giving an entomologist a bigger bug net and allowing them to swing it more times. It's not just insects and other creepy-crawlies. "It's the vertebrates that are absolutely, truly astonishing," says Andrew Ross, head of paleobiology for National Museums Scotland in Edinburgh.

In 2018, scientists reported 321 new species immaculately preserved in Burmese amber, bringing the cumulative total to 1195. One team recently argued that Burmese amber may boast more biodiversity than any other fossil deposit from the entire reign of the dinosaurs. "You think this can't even be possible," says Philip Currie, a paleontologist at the University of Alberta in Edmonton, Canada, "but it's happening."

Single fossils within that bonanza illuminate how creatures lived and where they fit into the tree of life. Taken together, the finds benchmark the birth of lineages and ecological relationships that still undergird modern ecosystems.

Most of that scientific bounty passes through the bustling market here in Tengchong. And before that, it emerges from a conflict zone.

Tracing amber to its source

In 2014, Xing sneaked into Myanmar, hoping to see the source of the specimens that had captivated him. The amber comes from mines near Tanai township in Kachin, where for decades Myanmar's army and the local Kachin Independence Army, an ethnic insurgency, have battled over control of lucrative resources such as jade, timber, and, most recently, amber. Foreigners are not allowed into Tanai. To make his clandestine visit, Xing first traveled across the border some 110 kilometers to Myitkyina, the Myanmar-side hub of the amber trade. When the road seemed safe, a friend smuggled him north dressed in a longyi, a traditional Myanmarese wrap skirt.

Xing and other visitors to the mines describe a lush terrain transformed into barren hillsides. Tents cover claustrophobic holes up to 100 meters deep but only wide enough for skinny workers, who say they are responsible for their own medical care after accidents. The miners dig down and, when they hit layers of amber, tunnel horizontally with hand tools to dig it out. They sort finds at night, to avoid publicizing valuable discoveries. Amber with fossil inclusions is the most precious, proof after weeks of uncertainty that a mine will be profitable. Reached by phone through an interpreter, miners say both warring sides demand bribes for the rights to an area and equipment—and then tax 10% of the profit.

Xing hasn't yet published his full conclusions from that trip, but he and others suspect the origins of the amber may be more complicated than thought. The oft-quoted age of 99 million years comes from radiometric dating of volcanic ash bought from a miner and published in 2012. But Wang Bo, a paleontologist at Nanjing Institute of Geology and Palaeontology (NIGPAS) in China, thinks the recent wave of amber has a range of ages. He had a friend with Myanmarese citizenship gather more recent samples of volcanic ash, which Wang says show that the amber deposits span at least 5 million years. "It's a period," he says, "not just a point."

Miners and traders aren't concerned with details of geology, however. After the amber is extracted and roughly sorted, scooters, cars, boats, and elephants carry it to dealers either in Myitkyina or straight across the border to Tengchong. Myanmar law explicitly bars exporting fossils without permission—but amber is classified as a gemstone and so is allowed to leave.

… Myanmar’s cultural heritage, paleontological heritage, is just being wholesale ripped out of the ground … Michael Engel, University of Kansas

China, however, taxes jewelry imports, so dealers here say they smuggle amber in—for example, in the wheel wells of cars. In Tengchong's market that "shadow economy" emerges into broad daylight, wrote anthropologist Alessandro Rippa at the University of Colorado in Boulder in a 2017 anthropological study. Local authorities not only tolerate, but police the market, which has been an economic boon.

Scientists didn't take long to notice. Since the 1920s, a small collection at London's Natural History Museum offered scientists their only glimpse of the diversity of life inside Burmese amber. Then, during a cease-fire in the late 1990s, a small Canadian company started to mine amber in Kachin. It shipped 75 kilograms of raw amber to Grimaldi. He found that each kilogram he acid washed, cut, and polished contained an average of 46 organisms. In the early 2010s, the market here started to boom just as amber mines inside China became tapped out. Demand rose for new amber sources—and that trickle of amber fossils from Myanmar turned into a flood.

A vertebrate parade

Centers of commerce Amber is mined in the Tanai region of northern Myanmar, then ferried to Myitkyina, where it is sold or smuggled into Tengchong, China. There, scientists and collectors vie for prize specimens. version="1.0" encoding="utf-8"? Guam Most of them 160 160 Most of them 90 Most of them 44 Most of them 6 0 500 Km 0 500 Km MYANMAR CHINA INDIA Indian Ocean Myitkyina Tanai Tengchong Yangon Kachin state Yunnan province Madrid Amber mines Amber and fossil markets

Before Xing's March visit to the bustling outdoor market, he had already arranged to make a purchase after seeing pictures sent to his phone. Now, in a dimly lit amber jewelry shop, a camera-shy 20-something broker from Myitkyina delivers today's prize: two lizards in amber. On one, the skin and flesh have vanished in patches, revealing delicate bones. Given the pace of commerce here, a museum, with its bureaucracy and budgeting process, could never compete for that specimen. Xing simply takes out his smartphone and taps a payment app to buy it for a few hundred dollars—a good deal, he says, because this piece is too cloudy and jumbled to make attractive jewelry.

In 2014, Xing began to cultivate a network of buyers here and in Myitkyina and teach them to spot the claws of a Cretaceous bird wing or to count the toes that would tell whether a foot came from a lizard or a dinosaur. Once he gets a tip, he texts a picture to specialists, hoping to figure out whether a specimen's likely scientific importance justifies steep prices. Only then will he decide to buy.

Receiving Xing's texts is "like Christmas every time," McKellar says. Scientists are aware that their identifications can boost prices. Once a specimen has been named as a bird, for example, it might go for tens of thousands or even hundreds of thousands of dollars. Wang adds, "They will use my word to make money."

"In an ideal world, we shouldn't be bartering and buying and selling fossils," says paleontologist Emily Rayfield of the University of Bristol in the United Kingdom, president of the Society of Vertebrate Paleontology, paraphrasing that organization's formal position. "But sometimes there's a need to do that to keep them in, or bring them into, the public trust."

At first, Xing used his own money to buy fossils. Then he persuaded his parents, both doctors, to sell their house in southern China to free up cash. He spent that money by 2016, and he and friends started a nonprofit called the Dexu Institute of Palaeontology (DIP), based in the southern Guangdong province in China, to acquire and house a permanent collection that makes specimens available for other scientists.

Xing has since published papers on enough vertebrates to fill a Cretaceous terrarium, including a baby snake fossil that preserved 97 fragile vertebrae, published in Science Advances; the front half of a 2-centimeter-long frog, in Scientific Reports; and his blockbuster result, a feathered dinosaur tail that appears to contain traces of hemoglobin, in Current Biology.

But Xing's first and most sustained success has been with tiny birds. Soon after he had built up his network, a source sent him a picture of the first bird discovered in amber. "The price was about the same as a new BMW, but we still got it," he says. "And we found more, and more, and more after that."

The birds hail from a primitive group called Enantiornithes that went extinct with the other dinosaurs. Amber preserves never-before-seen features of their skin and feathers and may even reveal internal details. "This is a whole new window into avian evolution," Clarke says.

For example, other Chinese bird fossils exhibited flaring tail feathers that had been squished flat inside sedimentary rock. Paleontologists assumed those feathers matched similar ornamental ones in modern birds, which have a central shaft built like a hollow tube. In December 2018, though, Xing published feathers from 31 Burmese amber pieces, which revealed an open, superthin central shaft. Given that those flimsy feathers always appear straight in fossils, they must have been able to snap into a rigid state, like a child's snap-on bracelet.

"Now we know, from these 3D amber specimens, that everything we think we see [from flattened fossils] is wrong," says Jingmai O'Connor, who studies Xing's bird fossils from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. In February, the team published another amber discovery: a bird's foot topped with feathers—an expected but previously unseen evolutionary step for modern birds, which later evolved scaly, featherless feet.

The Jurassic Park dream of fishing out DNA from amber hasn't yet come true, despite multiple tests in even very young amber, McCoy says. But amber researchers have reported other chemical traces lingering in their fossils: pigments that reveal how creatures shimmered under the mid-Cretaceous sun, and structural molecules such as chitin from arthropod exoskeletons and lignin and cellulose from plants. Last month, McCoy's group reported recovering amino acids from a feather in Burmese amber, bearing a chemical signature that suggested they had still been bound into fragments of proteins before the test. The next step: to actually sequence ancient proteins, which could offer researchers another way to track evolutionary relationships and understand how organisms lived.

But McCoy's experiment involved smashing amber-clad feathers to powder with a hammer. Scientists—and collectors—would prefer other methods to study trapped biomolecules. Researchers have started to experiment with synchrotron imaging, using intense x-rays that cause chemical elements in a sample to fluoresce at distinct wavelengths, for example. "It's going to take a decade for us to figure out how to truly utilize the wealth of information trapped inside these specimens," O'Connor says.

As they examine specimens, scientists stay alert for the products of clever forgers. One specimen marketed as Burmese amber and then subjected to chemical tests contained what would have been the first turtle in amber. "But it was fake," Xing says.

March of the hell ants

Across China at NIGPAS, 2100 kilometers away inside Nanjing's walled historic center, Wang pours tea. Then he starts to pull out bags of labeled insects in amber. Rare vertebrates may be the charismatic megafauna of Burmese amber, but invertebrates rule in numbers and diversity. Wang, a paleoentomologist, has amassed a 30,000-piece collection of plants and insects in Burmese amber, many bought here with funds from his institution. He still hasn't studied it all. "Eventually, we think maybe 4000 or 5000 species can be found," he says.

His lab employs an array of high-tech imaging systems to peer into specimens without destroying them. In one room, a laser confocal microscope causes delicate structures—like the multifaceted eyes of a fly, now splashed from the scope onto an adjacent monitor—to fluoresce. In another room, a computerized tomography (CT) scanner peers inside fossils to make 3D models of internal structure.

A tally of new species For decades, only a few pieces of Burmese amber reached scientists. Then in 2000, a trickle of specimens began. Starting around 2010, that trickle became a flood that has led to the discovery of hundreds of species. version="1.0" encoding="utf-8"? 1916 2018 Kachin amber mines boost production 50 100 150 200 250 300 321 3

By applying those techniques, Wang, like his rivals, has unearthed enough 99-million-year-old evolutionary gambits to fill a nature documentary. Take the lacewings, an insect group that today preys on ants and aphids. In one large glob of amber, the extended wing of a butterflylike lacewing shows a decoy eyespot that may have helped misdirect predators. In another, a lacewing larva looks for all the world like a liverwort plant. Still other lacewings have forest floor debris glued onto their backs, a camouflage strategy many modern insects still use.

"It's a pity that most of them became extinct," Wang says, "but we are lucky we found some hidden stories about them."

Some groups have no direct descendants, such as the Haidomyrmecines, nicknamed "hell ants." They evolved near the base of the ant family tree and sported sharp, sickle-shaped tusks that may have slammed upward to impale other insects. Some, the "unicorn" ants, also had a long top horn, probably used to pin prey in place. "These are like the tyrannosaurs of the ant world," Grimaldi says, "that you would never know existed if you studied modern living fauna."

Ancestral spiders offer another surprise. In early 2018, Wang and Huang Diying, a researcher at NIGPAS, separately published specimens in Nature Ecology & Evolution with spiderlike bodies trailed by long, scorpionesque tails. Now extinct, those arachnids were holdouts from a very early branch of spider evolution thought to have died out by some 250 million years ago. But in what is now Myanmar, they once crawled alongside the true spiders that persist today. Those protospiders also had silk-spinning organs, evidence that even early arachnids had that power.

Of all those riches, the most important may look lackluster: little beetles coated in dots of pollen. They are a clue to a dramatic and quick changeover in life's history that Charles Darwin called "an abominable mystery": the emergence of the flowering plants, which mostly rely on insect visitors to carry their pollen. Other amber specimens from the same ancient forest show pollen from an older group of trees, the gymnosperms—conifers and ginkgoes—which today are pollinated largely by wind. But some of the pollen on the beetles looks too big to be windblown. The amber, it seems, may capture the moment when many insect groups switched their feeding from gymnosperms to flowering plants, touching off the millions of years of coevolution that led to the extraordinary diversity of flowers and their pollinators today.

Studying the evolution of that partnership should help researchers understand why insect groups thrive or fail—a crucial question at a time when entomologists have begun to worry that ongoing climate change could drive a wave of insect extinctions, says paleoentomologist Michael Engel of the University of Kansas in Lawrence. "Burmese amber fits perfectly into this grand, unfortunate, tragic experiment that is going on with the world right now," Engel says.

A fully commercial ecosystem

After perusing the outdoor stalls here, Xing moves from shop to shop, sitting down at one elegant tea table after another to chat with owners. Under jewelry store glass counters, these shops showcase ferns, flowers, scorpions, fearsome spiders, and one tiny pinecone. New specimens emerge from the back in plastic bags. One shop even offers a baby bird, its delicate wing—with its telltale claw—clearly visible. But the dealer is asking about $145,000—too much.

By day's end, Xing's student has a padded backpack full of invertebrates in plastic cases, as well as the lizards. Next, Xing flies to the nearby major city of Kunming, China, to meet with Xiao Jia, a wealthy private collector and online dealer who lent him that first snake in a piece of amber for study.

Along the way, the hustle never stops. After Xiao's driver picks Xing up from the airport, his phone buzzes: A dealer in Myitkyina wants to sell what may be the first fragment of a beehive in amber.

Xing discusses buying it with Xiao. If neither of them grabs that specimen, someone else in the same small, deep-pocketed circle might—like Xia Fangyuan, a collector, dealer, and enthusiastic coauthor on about a dozen high-profile papers, who lives across the country in Shanghai, China, and competes with Xing for top specimens. Xia says he spends roughly $750,000 on Burmese amber per year, and grateful scientists like Wang have named species of cockroach, froghopper, parasitoid fly, and caddisfly for him. His vast collection, stored in a bank vault and brought out for visitors at his home, includes a bird, lizards, and a frog. His favorite specimen, he says, is a perfectly preserved insect: a praying mantis he bought for $22,000 that looks like it could cock its head at any moment.

Xia's collection also includes a curious shell bought from a dealer who claimed it was a snail. Suspecting that the specimen was something more, he lent it to Wang, who did a CT scan that revealed the internal chambers characteristic of an ammonite—an extinct marine cephalopod resembling a nautilus. The remarkable seashell must have been caught in resin in a beachside forest, perhaps after it was thrown onto land in a storm. Described in the Proceedings of the National Academy of Sciences (PNAS) last week, the specimen remains in Xia's private collection.

That arrangement isn't unusual. Chinese collectors hesitate to give specimens to museums outright, Wang says, because China's laws don't offer tax breaks for such donations. But some Western paleontologists are uncomfortable with publishing fossils that remain in private hands. A simple loan of a specimen isn't enough to ensure its long-term preservation or that other researchers can visit and study it for decades and centuries to come. "The whole point of science is that we're generating and testing hypotheses," Rayfield says. "If we're not able to study specimens anymore, then it simply becomes an exercise at taking someone at their word."

And yet PNAS is far from the only journal to have published specimens from China's private Burmese amber collections. Science Advances (part of the Science family of journals) has also published papers on specimens belonging to Xia, as well as on the amber snake, now housed in an exhibit in the back of Xiao's toy store in a Kunming mall. (Xiao and DIP have arranged for the institute to own that specimen, but it is loaned back to Xiao until 2027.)

Pressed on the status of their specimens, both Xiao and Xia—and the scientists with whom they collaborate—say they plan to turn their collections into private museums and that they are committed to accepting requests for study from outside researchers. The PNAS paper lists the ammonite specimen, for example, as belonging to the Lingpoge Amber Museum in Shanghai, an institution that Xia says he is preparing. He says he is negotiating with his district-level government for space. Asked whether that situation meets their policies, the PNAS editorial board issued a written response: "The authors of this article have assured us that the fossil will be made available to qualified researchers."

Experience leaves some amber researchers wary, however. Engel recalls once asking to visit a published specimen from an amber deposit in Jordan. It was housed in what seemed to be a museum that turned out to be run by a collector. "It was basically his basement," Engel says. "He says, ‘Oh yeah, sure you can examine it—for $10,000.'"

Yet the allure of the amber fossils may grow, regardless of ownership—because of scarcity. The supply of amber is far down from its height around 2015, dealers say. As quickly as that window into the Cretaceous opened, it might already be slamming shut.

The end of Burmese amber?

In June 2017, helicopters from Myanmar's army buzzed over Tanai. According to news reports, they dropped leaflets warning amber miners and other residents to flee. Airstrikes and roadblocks followed, and Myanmar's army has since pried away the amber mining areas from the Kachin Independence Army. A 2018 report by a United Nations investigator indicated that the actions killed four civilians and trapped up to 5000 people in the area. Citing the army's broader conduct, including in Kachin, another U.N. fact-finding report called for Myanmar's top generals to be investigated for genocide and crimes against humanity.

Two former mine owners, speaking through an interpreter in phone interviews, say taxes have been even steeper since government troops took control of the area. Both shut their mines when they became unprofitable after the government takeover, and almost all deep mines are now out of business, dealers here corroborate. Only shallow mines and perhaps a few secret operations are still running.

Tracing how revenue from amber funds Myanmar's army and ethnic militias is hard. "As a consumer," says Donowitz, "by increasing the values of those commodities, by participating in those trades, you are part of that conflict."

That's not the only ethical cloud over these specimens. Many fossil-rich nations, including China, Canada, Mongolia—and Myanmar—have written laws to keep unique fossils inside their borders. Myanmar's rules threaten violators with 5 to 10 years in prison, thousands of dollars in fines, or both. As Burmese amber fossils slip through the gemstone loophole, "It's like Myanmar's cultural heritage, paleontological heritage, is just being wholesale ripped out of the ground and distributed around the world," Engel says.

Xing stresses he wants to extract scientific details, not to own specimens. He says he's sensitive to the issue because many Chinese historical objects now sit in foreign museums. "If one day Myanmar gets peace, and they want to build a museum for amber or build a museum for natural history, [Xing's own institute] would love to return all the specimens to Myanmar," he says. "It's not going to come free. But yeah, we'd love to return them."

Some paleontologists also hope to see a Burmese amber collection near the mines or at least within the country's borders. "If Myanmar wanted to build a museum about amber," Grimaldi says, "it would be totally fun to lend my expertise in helping to design and build that. It would be magnificent, and I think it should be done." In recent months, one private amber museum opened in Yangon, Myanmar's largest city. But in addition to education, its English website also offers amber lots for sale, custom jewelry and fossil procurement, and escorted buying tours to amber markets, suggesting the museum is about commerce as well as preservation.

For residents in Tanai, questions about who owns fossils pale in the face of day-to-day security issues. "Right now there is no stability and no rule of law," says one out-of-work miner in a phone call.

But as the formal interview ends, he has a request. He says the miners digging up the amber don't know why scientists care about the insects and other creatures entombed inside it. "If you know," he says, "please share with us?"

Wudan Yan, a journalist based in Seattle, Washington, contributed reporting from Yangon, Myanmar.

*Update, 29 May, 12:20 p.m.: This story has been updated to reflect the current ownership of the snake in amber specimen.