A staggering quantity of fish in a vanished German lake suggests the debt humans owe to extinct species from 48 million years ago.
A half-mile wide abandoned strip mine located in the middle of a woodland around twenty minutes from the central German city of Darmstadt. Scrubby shrubs now cover the fall, and dirt trails wind by ponds filled with vivid green algae created by rainfall. The Messel Pit is a 200-foot-deep gash in the middle of a forested countryside that doesn’t initially appear worth protecting, much less visiting. However, since 1995, it has been recognized as a Unesco World Heritage Site because of a sequence of tectonic events that began around 48 million years ago.
Then, in what scientists refer to as the Eocene, the earth was a totally different place. Temperatures rose due to a greenhouse effect caused by higher than current quantities of carbon dioxide in the atmosphere (at least temporarily). Giant crocodilians swam among the ferns in the warm waters of the Arctic. Antarctica was covered in a tropical rainforest. Though India was still on the track to join Asia to form the Himalayas, the outlines of the continents would be largely identifiable. Europe was a huge archipelago rather than a generally continuous landmass because sea levels were around 150 feet higher than they are now.
The area that is currently occupied by the opulent, glass-and-concrete Messel Pit visitor center—which offers a virtual borehole tour and a voyage back in time—was, in the Eocene, next to a depression that was, at its widest point, about two miles broad. The lake turned into a death trap for a great number of creatures, and features of the buried carcasses were astonishingly preserved thanks to a combination of geochemistry and millions of years of accumulating plant and mineral deposits.
As any schoolchild knows, fossil fuel is produced by decomposing animal and vegetable matter that has been squeezed and dried under temperature conditions over millions of years. In this case, the fossil fuel is predominantly oil shale, which is composed of layers of soft gray stone mixed with oil. From the late 1800s until the 1970s, when the open-pit mine stopped and was abandoned by all save a tiny handful of persons determined to extract the fuel instead of the fo̧̖̕ʩ̧, such resources drew miners.
News of the amazing discovery quickly circulated. The site has been treasured as the largest fossil treasure of its kind, save for a possibly understandable case of civic shortsightedness when the local government considered converting the enormous hole in the ground into a garbage dump—a proposal that paleontologists and others ѕɻагрɩy opposed for 20 years, finally winning in 1992. According to paleontologist Ken Rose of Johns Hopkins University, “everyone in vertebrate paleontology knows Messel.” Really, nowhere else in the world comes close to this. That era is when most of what we know now originated.
From 56 million to 34 million years ago, the Eocene marked a significant turning point in the history of life on Earth. We ourselves owe a great deal to this period, as it was during this time that mammals emerged and adapted to fill the ecological niches left by the extinct dinosaurs. Numerous entire mammal skeletons can be found at Messel Pit, frequently with the traces of fur and feathers still evident in the surrounding rock. There are glimpses of the distant ancestors of ѕрeсіeѕ that we know today in the form of primitive opossums, horses the size of fox terriers, an anteater, eight bat ѕрeсіe̕, and a lemur-like monkey that may represent an early branch on the human family tree. There are many more fo̕ѕіɩ̕.
Although the prospect of tourists trampling over their excavation sites is often met with disapproval by paleontologists, guided tours are available at Messel Pit, which is managed by the Senckenberg Research Institute in Frankfurt. On an autumnal day, I accompany geologist Marie-Luise Frey from the 2010-opened $6.5 million visitor center to the bottom of the pit. She guides me away from the asphalt pathway and onto the mild incline of a newly concluded dig. Dried-out oil shale flakes under my boots. Paleontologists used a chainsaw to cut through thick layers of shale, removing enormous chunks before gently prying them apart to search for hidden fossils. The location of these layers is revealed by a ѕɻагр сoгοeγ.
The excavation’s edges bear a resemblance to the pages of a book with bleeds. The majority of the oil shale is still water. Frey describes in German how the oil shale becomes as flaky as phyllo dough as it dries and finally collapses to dust. I’m attempting to visualize the area as it was previously, but I’m having trouble transporting myself to a rainforest that existed 48 million years ago despite the brisk autumn air, changing leaves, and the rumbling of machinery at a nearby gravel plant.
I take up one of the oddly shaped stones that I’ve noticed. It resembles a praline in size. Frey tells me wryly, “Das ist ein Koprolith,” which is paleontologist jargon for a piece of fossilized excrement. “You can still tell what they ate by examining them,” she explains, implying that this one was probably generated by a really large fish. Eager to find out how this place came to be, I follow Frey deeper into the abyss.
Around 50 million years ago, a vein of molten rock and subterranean water came into touch. A crater with steep walls was formed by the high-pressure steam that erupted. The lake that formed when water crept in was more akin to a drinking glass than a soup bowl. Any animal that gave way soon reached the bottom.
However, this still doesn’t explain why so many land mammals died here, in addition to birds, bats, and insects. According to one idea, creatures close to the coast were suffocated by carbon dioxide that periodically bubbled up from beneath Lake Ottom. An additional hypothesis is that a portion of the summertime algae blooms were toxic, injuring animals who had selected the ideal location and time to quench their thirst. Alternatively, smaller animals might have fallen nearby and been carried in by swift-moving streams or minor floods.
There were no predator feeders nearby to eat the dead and dying animals as the lake was so deep that oxygen couldn’t get near the predators. As the algae covering the lake’s surface continued to flourish and die, layers of fine clay and dead microorganisms accumulated at the bottom. Every layer had the thickness of a hair strand. An inch of mud built up over 250 years. Over many millions of years, algae and other organic materials transformed into oil shale, while plants and animals were preserved like flowers sandwiched between book pages.
Paleontologists have found thousands of fossils at Messel Pit, including specimens from about 45 different mammal taxa. These discoveries are essential to comprehending the evolution of warm-blooded organisms. Approximately 200 million years ago, mammals and dinosaurs made their appearance almost simultaneously. However, dinosaurs crowded out any ecosystem because they were so adapted to it. Mammals were mainly little organisms that survived by eating insects in the shadow of night. Paleontologist Thomas Lehmann of the Senckenberg Research Institute explains, “They just tried to stay out of the way.” Thus, for almost 150 million years, it continued.
Then, seemingly, an asteroid or comet struck Earth 66 million years ago, drastically altering the temperature and ultimately eradicating the huge reptiles. This is when everything changed in an instant. The variety of species seen in the Messel Pit indicates that mammals scurried to occupy every available ecological niche. According to Lehmann, “They really tried everything—flying, jumping, running, living in trees, and eating ants.” “Messel is an excellent laboratory to study what life might have given us, from an evolutionary perspective.”
Perhaps, but didn’t in a lot of situations. The species in Messel’s collection that appear startlingly familiar yet have no living relatives may be the most fascinating. Children gathered in the visitor center to witness a conservator using toothbrushes, dental picks, and scalpels remove layers of oil shale from a fossil that was discovered a few weeks prior. The ĕkeɩetoο of Ailuravus macrurus resembles a big squirrel, in my opinion.
With its bushy tail included, its length is three feet. The fossilized digestive tract of the species is traced by a black smear near its ribs. Ailuravus is not an ancestor of squirrels despite having a tail. Ailuravus and all of its relatives perished more than 37 million years ago, therefore it’s a very sad end. Why? Perhaps they react differently to climatic change, to a competitor who is better suited, to alternative food sources, or just to plain luck.
The likeness of Ailuravus to a contemporary squirrel is an illustration of eⱱoɩᴜtіoпагу convergence. When adaptations take place throughout time, essentially similar solutions—like bushy tails or strong, kangaroo-like hind legs—may appear in many species. Lehmann compares it to building several forms using the same Lego set.
And the Messel Pit has a ton of formations. Paleontologists have gained unique insights into the adaptive strategies—some successful, others unsuccessful—adopted by mammals for food, locomotion, and even reproduction from the beautifully preserved fossils. Fossilized leaves and grape seeds, for example, show that the tiny prehistoric horse was a browser rather than a grazer since it was eating what it found on the forest floor. Additionally, eight fossilized examples of pregnant mares carrying a single foal were discovered by the paleontologists. This finding implies that early horses had already adapted to living in herds, as cooperative care would be the most effective means of ensuring the survival of limited numbers of progeny.
These discoveries transform the area from a cemetery into a time capsule with a 48 million-year-old ecosystem. Jens Lorenz Franzen, a seasoned paleontologist who worked at the Senckenberg Research Institute and assisted in confirming some of Messel’s most amazing discoveries, says, “It’s not only paleontology, it’s biology.” “We are able to rebuild that eγа’s living environment.”