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Dinosaur nest found in South Africa, Daderot via Wikimedia Commons // CC0 1.0

6 Types of Fascinating Trace Fossils You Can Visit

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Dinosaur nest found in South Africa, Daderot via Wikimedia Commons // CC0 1.0

Trace fossils (otherwise known as ichnofossils) are an echo of ancient life, providing evidence of animal activity in the past. Unlike normal fossils, which reveal the body of an animal in death, trace fossils show us how an animal behaved in life. Trace fossils can take many forms, including fossilized animal burrows, footprints, tracks, trails, nests, eggs and, of course, fossilized poop. Visiting them can offer a chance to learn more about the insights scientists have made from these amazing finds.

1. WHERE WE WALKED

Cast of the Laetoli footprints at the Smithsonian Museum of Natural History in Washington, D.C. Image via Tim Evanson, Wikimedia // CC BY-SA 2.0

Footprints are perhaps the most evocative of trace fossils, allowing us to literally walk in our ancestors’ shoes. Some are transitory, like the ones found in 2013 in Norfolk, England, where a team of researchers from the British Museum noticed that heavy seas had washed away layers of silt, leaving the uncovered estuary mud pock-marked with ancient footprints. Unfortunately, the 800,000-year-old prints eroded in a matter of weeks, but their existence was well-documented in digital images and will continue to be studied. Other footprints have lasted far longer: One pair recently discovered in British Columbia may be 13,200 years old, which would make them the oldest found in North America.

Where to see them: The most famous site containing footprint trace fossils is the Laetoli trackway in Tanzania. Footprints of early hominins from 3.6 million years ago were uncovered here, proving that our early ancestors walked upright. Visitors hoping to see the actual trackway will be disappointed, since it’s not open to visitors, but a cast of the footprints can be seen at the nearby Olduvai Gorge Visitor Centre.

2. WHERE ANIMALS MOVED

Climactichnites and ripple marks from Wisconsin, at the National Museum of Nature and Science in Tokyo. Image via Momotarou2012, Wikimedia // CC BY-SA 3.0 

Some of the most intriguing trace fossils are trackways left preserved in sediment. Because the tracks are not generally found alongside the fossil of an actual animal, it can be very difficult for scientists to uncover the type of creature that made the trackway. In some cases, such as soft-bodied worms—which would not leave bodily evidence in the fossil record since they have no skeleton—trace fossils of their castings are the only evidence for their existence. Because fossilized trackways are created where the creature lived and moved, they can often help researchers to discover more about an animal's habitat and behavior.

Where to see them: A great example of a fossilized trackway can be found in the Smithsonian National Museum of Natural History in Washington D. C. Here, visitors can see an eight-foot tall cast of trackways made by Climactichnites, a two-foot long slug-like creature.

3. PLACES ANIMALS CALLED HOME

Asteriacites from the Devonian of northeastern Ohio. Image via Mark A. Wilson, Wikimedia Commons // Public Domain

Asteriacites, the fossilized remains of starfish or ophiuroid burrows, are some of the most beautiful trace fossils. Most common in Jurassic rock formations, the indentations are created by the starfish digging their arms into the soft sediment. They are especially useful for scientists, since these trace fossils can leave an impression of the animal’s actual body. Other common resting traces are left by trilobites.

Burrow trace fossils, on the other hand, are most frequently associated with small burrowing sea creatures or bivalves, such as clams.

Where to see them:  An Asteriacite fossil can be seen at the Peabody Museum of Natural History at Yale University in Connecticut, where they have a world-renowned Invertebrate Zoology department.

4. WHERE ANIMALS ATE

Bitemarks in the fossil record can point to beavers building their dams, insects nibbling a leaf, or—in some rather more gruesome cases—dinosaurs gnawing their fellow dinosaurs. Unfortunately, it can be very difficult to identify which animal was eating the victim by toothmarks alone, but occasionally identification is made possible when part of a tooth has been left embedded in the bone. For example, a fossilized pterosaur bone was found in Alberta, Canada, with gnaw marks on it and a partial tooth embedded in it; analysis later indicated it was from the Saurornitholestes, a Late Cretaceous dinosaur similar to the more famous (thanks to Jurrasic Park) Velociraptor.

Where to see them: At the La Brea Tar Pits in Los Angeles, visitors can see some amazingly well-preserved Ice Age fossils, with some revealing gnaw marks left by insects and rodents.

5. WHERE ANIMALS WERE BORN

Protoceratops nest discovered in Mongolia. Image via Internet Archive, Wikimedia // No known copyright restrictions

There is some dispute over whether eggs can be classified as trace fossils or body fossils. Certainly where there is embryonic matter preserved inside the egg, they are seen as body fossils. However, fossils of nests can reveal much about the behavior of a dinosaur or other animal, by revealing where they chose to nest. Dinosaur nests have only ever been found on the ground, suggesting that they nested like modern reptiles and birds such as penguins.

Where to see them: The Natural History Museum in London has the nest of a Protoceratops, a small horned dinosaur, on display. The nest and a clutch of eggs were uncovered in the Gobi desert in Mongolia and are over 80 million years old.

6. POOP

A coprolite named "Precious," discovered in South Carolina and on display at the Poozeum. Image via Poozeum, via Wikimedia Commons // CC BY-SA 4.0

An animal’s fossilized poop (or coprolite) can reveal a lot about their diet, including whether they were an herbivore or a carnivore. For example, Tyrannosaurus rex coprolites indicate that they did not pick at their food, but devoured everything, bones and all. Geologist William Buckland was the first to identify the strange “fossil fir cones” as feces, and coined the name coprolites in 1829. In 2014 a private collector paid $10,370 for a 40-inch long coprolite. Unfortunately, many paleontologists think it may have been wrongly identified, and is merely a blobby mass of the mineral siderite.

Where to see them: The world’s largest collection of coprolites can be seen at the South Florida Museum in Bradenton. Dubbed the “poozeum,” the amazing collection boasts 1277 coprolites, found across eight countries and 15 states.

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science
6 Pioneering Facts About Mary Leakey

Fossil bones and the earliest footprints of our human ancestors are just a few of Mary Leakey’s groundbreaking discoveries. Get to know the legendary paleoanthropologist, and learn how her serendipitous finds forever altered scientists’ understanding of human origins.

1. MARY LEAKEY WAS A BORN EXPLORER.

Mary Leakey (1913-1996), née Mary Nicol, was destined to be an explorer: Her father, Erskine Nicol, was a landscape painter, and the family traveled extensively through France, Italy, and Switzerland. While staying in a commune in southern France, 12-year-old Mary became interested in archaeology after meeting Elie Peyrony, a French prehistorian excavating a cave. Mary dug through his tiny finds—which included fine points, scrapers, and flint blades—and sorted them into an amateur classification system.

2. FOSSIL HUNTING WAS IN HER BLOOD ...

Leakey’s parents were artists, but hunting for fossils was part of her heritage: Her maternal great-great-grandfather was John Frere, an 18th-century English government official and antiquarian who’s credited with first recognizing Stone Age flint objects as early weapons and tools.

3. ... BUT SHE WASN'T A GREAT STUDENT.

Leakey was intelligent, but she also had a rebellious streak. As a teen, she was expelled from several Roman Catholic convent schools—once for intentionally creating an explosion in a chemistry lab. Figuring she wasn’t cut out for a classroom, Leakey never finished high school, and decided to pursue independent studies in art, geology, and archaeology at the University of London instead. (“I had never passed a single school exam, and clearly never would,” the scientist later wrote in her 1986 autobiography Disclosing the Past.)

4. LEAKEY WAS AN ARTIST WHEN SHE MET HER FUTURE HUSBAND AND RESEARCH PARTNER, LOUIS LEAKEY.

Mary Leakey—who inherited her father’s artistic skills— ended up working as an illustrator for archaeological digs. An archaeologist introduced her to Cambridge University paleontologist Louis Leakey, who needed an illustrator for his book Adam’s Ancestors (1934). The two became lovers, but their union resulted in scandal, as Leakey was still married at the time. The couple married in 1936, after Leakey divorced his first wife.

5. MARY LEAKEY'S FIRST BIG DISCOVERY WAS PROCONSUL AFRICANUS.

Mary Leakey's first major discovery came in 1948 when she found a fossil skull fragment of Proconsul africanus, an ancestor of apes and humans, which later diverged into two separate species. The fossil was thought to be more than 18 million years old.

6. ANOTHER ONE OF MARY LEAKEY'S FAMOUS FINDS CAME COURTESY OF ELEPHANT POOP.

In 1978, Leakey was on an expedition in Laetoli, in Tanzania, when members of her camp engaged in a spirited elephant dung fight. A scientist fell down, and he noticed strange indentations on the ground that had been recently exposed by erosion. They turned out to be tracks made around 3.7 million years prior, from animals that had walked over damp volcanic ash. Examining these prints took several years, but the team's efforts paid off when Leakey noted that one of the prints seemed to be made by a hominin. This discovery showed that early humans began walking upright long before scientists thought they had.

Additional source: Ancestral Passions: The Leakey Family and the Quest for Humankind's Beginnings, Virginia Morell

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Stones, Bones, and Wrecks
Researchers Unveil an Unusual New Theory For How Easter Island’s Statues Were Made
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Wikimedia Commons // Public Domain

The Moai statues of Easter Island present one of the world's greatest technical mysteries. The stone heads (actually full bodies) that dot the island in the South Pacific are massive and number in the hundreds, prompting archaeologists to wonder how they got there in the first place. Now, as Newsweek reports, a group of researchers believe they're closer to finding an answer.

European sailors first arrived on Easter Island in 1722 and were greeted by a native population of 1500 to 3000. Along with the residents were 900-odd statues carved from solid rock, meaning there were fewer than four people for every massive monolith.

How was such a thin population able pull off such an impressive feat of architecture? According to researchers from Chile, New Zealand, and the U.S., it's possible they had help. Their new study published in the journal Frontiers in Ecology and Evolution suggests that the statues were carved and erected at a time when Easter Island supported a much larger population. Using data from the island, they estimated just how high the island's numbers may have reached.

Easter Island has the agriculture potential to sustain a maximum population of 17,500, researchers say. This estimate is based on the weather and soil quality of the island, 19 percent of which is capable of growing the sweet potatoes that fed inhabitants. "Despite its almost complete isolation, the inhabitants of Easter Island created a complicated social structure and these amazing works of art before a dramatic change occurred," lead author Cedric Puleston said in a statement.

If the Moai were constructed by a much larger group than the Europeans encountered, that would clear up some of the mystery surrounding the island. But it would also raise more questions. How, for instance, did the population fall so quickly in the few centuries between the statues' construction and first contact with Europeans? One theory is ecocide, which happens when an area is exhausted of its resources faster than it can replenish them.

The mystery of how the towering monoliths were transported across the island after they were built still remains. The indigenous people told Dutch explorers that the Moai walked themselves, an explanation an MIT professor put to the test when he designed a 2000-pound sculpture that could be shimmied long distances. But despite the numerous theories, hard evidence related to the figures' origins remains scarce.

[h/t Newsweek]

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