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

6 Types of Fascinating Trace Fossils You Can Visit

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


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.


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.


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.


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.


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.


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.

Penn Vet Working Dog Center
Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.

Dan Kitwood, Getty Images
This Just In
Flights Grounded After World War II Bomb Discovered Near London City Airport
Dan Kitwood, Getty Images
Dan Kitwood, Getty Images

London City Airport grounded all flights on the night of February 11, after a World War II bomb was found in the neighboring River Thames, The Guardian reports.

The half-ton bomb was revealed Sunday morning by development work taking place at the King George V Dock. Following its discovery, police set up a 702-foot exclusion zone around the area, closing local roads and shutting down the London City Airport until further notice. According to the BBC, 261 trips were scheduled to fly in and out of London City Airport on Monday. Some flights are being rerouted to nearby airports, while others have been canceled altogether.

The airport will reopen as soon as the explosive device has been safely removed. For that to happen, the Met police must first wait for the river's tide to recede. Then, once the bomb is exposed, they can dislodge it from the riverbed and tow it to a controlled explosion site.

The docks of London’s East End were some of the most heavily bombed points in the city during World War II. Germany’s Blitz lasted 76 nights, and as the latest unexpected discovery shows, bombs that never detonated are still being cleaned up from parks and rivers more than 75 years later.

[h/t The Guardian]


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