Originally published 2019-04-15.
A praying mantis about half an inch long, trapped in a polished nugget of Dominican amber, sold through Heritage Auctions in Dallas in 2016 for $6,000. The insect is unusually complete: legs, spines, antennae and even the colour patterns on its limbs are visible. The auction house dated it to the Oligocene epoch, 23 to 33.9 million years ago, though many geologists place Dominican amber somewhat younger, at around 15 to 20 million years. Either way, it is a rare, detailed snapshot of an insect that lived in a tropical forest long before humans existed.
Here is how insects end up in amber, why a mantis is a prized find, what a 99-million-year-old baby snake in amber added to the story, and why none of this brings us any closer to Jurassic Park.
How an insect becomes trapped in amber
Amber begins as resin, the sticky substance some trees produce to seal wounds and defend themselves against insects and fungi. Most resin simply decays in sunlight and rain. Occasionally, though, a blob of fresh resin engulfs a small animal and is then buried in sediment, often in river deltas or coastal lagoons.
Under burial, heat and pressure slowly drive off volatile compounds and link the resin's molecules into long chains. The resin first becomes copal, a semi-hardened material that is still relatively young, and over millions of years it turns into true amber. Because resin dehydrates what it traps and seals out oxygen and microbes, soft tissues such as wings, hairs and eyes can survive in astonishing detail.
Why Dominican amber is special
Amber from the Dominican Republic formed from the resin of an extinct tropical tree, Hymenaea protera, a member of the same genus as several living tropical legume trees. It is mined mainly in the Cordillera Septentrional in the north of the island and around Bayaguana and Sabana de la Mar in the east. Compared with the better-known Baltic amber, Dominican amber is usually clearer and richer in inclusions. Ants, termites, beetles, a small gecko and even a tardigrade have been found preserved in it, allowing scientists to reconstruct an entire lost forest.
The 2016 mantis and what made it valuable
Heritage Auctions' lot description stressed how rarely mantises turn up in amber at all, and how often those that do are distorted or missing limbs after struggling in the resin. This specimen is intact, with its raptorial forelegs folded, compound eyes visible and long antennae still in place. The nugget, roughly 1.75 by 1.25 by 1 inch, also contains three well-preserved click beetles, which adds both scientific interest and collector value.
Mantises are ambush hunters, so they spend long stretches standing still on bark and leaves. That habit may explain why relatively few were caught: active crawlers such as ants and flies are much more common in amber.
A word on the age
Dating Dominican amber has been debated for decades. Early estimates in the 1990s placed some deposits at up to 40 million years old. More recent work, based on marine microfossils in the surrounding rock, points to a Miocene age of roughly 15 to 20 million years for most of it. Auction houses often quote the older range. For a specific piece, the true age depends on which mine it came from, which is not always documented.
A baby snake in 99-million-year-old amber
Amber can also preserve vertebrates. In July 2018 an international team led by Lida Xing, with University of Alberta palaeontologist Michael Caldwell among the authors, described in Science Advances the skeleton of a newborn or embryonic snake trapped in amber from northern Myanmar. They named it Xiaophis myanmarensis. The amber comes from deposits in the Hukawng Valley that have been dated to about 99 million years ago, in the Cretaceous period, when dinosaurs were alive.
The specimen is the first known fossil of a baby snake from that era. Its vertebrae show features not seen in other fossil snakes, and the researchers placed it near the base of the snake family tree. Caldwell explained what makes amber so valuable to palaeontologists in a memorable way: "Amber collects everything it touches — kind of like super glue — and then holds onto it for a hundred million years." Because the piece also caught plant matter and insects from the forest floor, it showed the snake lived in a forest rather than in water.
An ethical footnote
Burmese amber has become controversial. The mines are dangerous, and taxes on the trade have been linked to armed conflict in Kachin State. In 2020 the Society of Vertebrate Paleontology called for a moratorium on publishing fossils bought from Myanmar after June 2017, the year the military took control of the mining area. The snake was described before that date, but anyone buying amber today should ask where it was mined.
Can we get DNA out of amber? The Jurassic Park myth
The 1993 film Jurassic Park made amber famous by imagining scientists extracting dinosaur blood from a mosquito trapped in resin and cloning dinosaurs. It is a great story, but it does not work in real life.
- No preserved blood has been found. Mosquitoes do occur in amber, but none has yielded dinosaur blood.
- DNA breaks down. Even in ideal conditions, DNA degrades over time. Amber helps by drying out tissue, and some scientists once speculated it could protect DNA for very long periods, but claims from the 1990s of DNA recovered from ancient amber insects were not reproduced and are now generally attributed to contamination.
- Even young resin fails. A 2013 study could not recover DNA from insects in copal only a few centuries to thousands of years old.
What amber does preserve beautifully is shape and structure, which is why it is so useful for studying ancient anatomy and ecosystems.
Tips if you want to buy amber with an insect
- Watch for fakes. Copal, plastic and pressed amber are commonly sold as genuine amber with inclusions. Reputable dealers will explain how a piece has been tested.
- Ask for the origin. A named country and ideally a mine help establish age and avoid ethically problematic sources.
- Expect to pay for quality. Complete, clearly visible predators such as mantises, spiders and scorpions are among the most expensive inclusions.
- Consider a museum loan or donation for a scientifically important piece, so researchers can study it.
Why these tiny fossils matter
Bones and shells tell us a great deal, but amber offers something rare: soft bodies, colours and the small creatures that usually vanish without trace. A single mantis or a baby snake can show how ancient animals hunted, where they lived and what shared the forest with them. That is the real wonder of the piece that sold in 2016, and it does not need any fiction to impress.
Sources: Heritage Auctions (images and lot description); My Modern Met; Wikipedia: Dominican amber; Wikipedia: Xiaophis; Wikipedia: Burmese amber; Wikipedia: Amber.
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