An Ultimate Guide to Coprolite: The Fossilized Feces

Leave a comment / / Updated on: 24th September 2023

An Ultimate Guide to Coprolite

To study prehistoric animals like dinosaurs, scientists rely on bones, teeth, and other body fossils. 

While they can be very instructive, these body fossils don’t tell us everything there is to know about these prehistoric animals. 

Pieces of bones and even well-preserved, almost-complete body fossils only tell us what the animal looked like when it was alive and might provide some clues about their ecosystem. 

But animals are more than how they look. 

Artwork of a male and female brachiosaurus grazing food
Artwork of a male and female brachiosaurus grazing food | Mark Garlick via Getty Images

To truly understand prehistoric animals, we have to uncover information about their diet, how they digested food, and the interactions they had with other animals within their ecosystem.

For these, scientists rely on a weird but fascinating type of fossil known as coprolite. 

That’s the fancy word to describe fossilized feces, and this type of fossil is more common than you might think. 

In this article, we’ll explore the concept of fossilized feces to understand what it is and its significance to paleontologists. 

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

What is Coprolite?

Coprolite | wwing via iStock

Coprolites are essentially remnants of animal waste material preserved in ancient rocks. 

They’re fossilized poops of animals that lived several million years ago and have undergone years of geological transformation to become something valuable for our study of these ancient animals. 

Coprolites come in various shapes and sizes, and they reflect the diversity of the prehistoric creatures that produced them. 

Some may be large and smooth, resembling twisted logs. 

Others are smaller and may be packed with bone fragments, suggesting that the animal that produced them had a carnivorous diet. 

Formation of Coprolites

Coprolites are fossilized excrement of primitive animals
Coprolites are fossilized excrement of primitive animals | Michel VIARD via iStock

Every animal poops — that includes prehistoric animals like dinosaurs too. 

Throughout a dinosaur’s life, it will produce piles of poop, but not all of these will be preserved as fossils. 

In fact, bones, teeth, and other hard parts are more likely to be preserved than organic materials like excrement. 

Coprolites will only be formed if the feces is quickly covered by a mineralizing agent shortly after production. 

A large coprolite of a carnivorous dinosaur found in Harding County, South Dakota
A large coprolite of a carnivorous dinosaur found in Harding County, South Dakota | Poozeum via Wikipedia Poozeum

If mineralization occurs successfully, the feces will stop decomposition, forming a coprolite.

The journey from fresh excrement to solid fossils involves an intricate interplay of various conditions and natural processes. 

For feces to get mineralized, the animal has to excrete waste in an environment conducive to fossilization. 

This includes sediment-rich areas or areas where deposition occurs actively, such as mudflats, riverbanks, or lake beds. 

Sediment-rich hillside | Jacob Sanek via GettyImages

In such areas, the waste can quickly become buried. 

This protects them from the elements and scavengers.

Once buried, the feces are shielded from decay because the lack of oxygen and other factors slow down the decomposition process. 

However, what truly allows the formation of coprolites is the infiltration of minerals into the feces from the surrounding sediment. 

The organic components of the feces are gradually replaced by minerals. 

This creates a petrified replica of the original waste material, allowing the coprolite to retain its shape and structure while transforming it into a solid form that can be preserved for several millions of years.

Unveiling Ancient Diets: What Can Coprolites Tell Us?

A large Miocene coprolite from South Carolina, USA
A large Miocene coprolite from South Carolina, USA | Poozeum via Wikipedia CC BY-SA 4.0

While studying petrified poop might seem like a less-glamorous side of paleontology, it is a very important one. 

Coprolites are classified as trace fossils.

These are fossils that are not formed from the animal’s actual body but from something that came from their body.

In this case, it is preserved remnants of the animal’s feces, which can be used to deduce what it ate and reveal the eating habits of these ancient creatures. 

Cross-section of mammoth footprints
Cross-section of mammoth footprints | Wilson44691 via Wikipedia Public Domain

Other examples of trace fossils include burrows and footprints. 

Ancient Diets Revealed by Coprolite

To study coprolites, scientists examine the composition, size, shape, and texture of this fossil. 

In some cases, the coprolite may also contain undigested remnants. 

Based on these, it is possible to deduce whether the animal that produced the poop was a carnivore, omnivore, or herbivore. 

For instance, if the coprolite contains plant matter or cellulose, it’s probably from a herbivorous animal.

A coprolite with many small inclusions and one has a complete toe bone from a small deer called a leptomeryx | Poozeum via Wikipedia CC BY-SA 4.0

Similarly, coprolites rich in bone fragments came from an animal with a carnivorous appetite. 

Some coprolites might even contain evidence of the creature’s digestive processes, offering insights into its physiology.

Reconstructing Food Chains

Another intriguing aspect of coprolite analysis is its usefulness for reconstructing prehistoric food chains. 

Since an animal’s diet usually consists of things that are present in its surroundings, identifying what an animal ate can help scientists infer its position within its ecosystem.

For instance, a coprolite containing the remains of small prey animals suggests that it came from an animal higher up in the food chain. 

A large coprolite from South Carolina, USA
A large coprolite from South Carolina, USA | Poozeum via Wikipedia CC BY-SA 4.0

Similarly, coprolites from a herbivorous animal means the animal that produced it was a primary producer. 

In fortunate situations where coprolites from different organisms within the same area and period are preserved, scientists can study these remains to piece together a complex web of interactions between these species.

Coprolites can also help scientists unravel the nature of interactions between predators and prey, shedding light on the strategies employed by ancient predators to catch their prey. 

The presence of prey remains with crushed and shredded bones suggests that the predator probably chewed up the remains before swallowing them. 

In contrast, relatively intact body parts suggest the prey was swallowed whole. 

Thus, coprolites can reveal vital information about the hunting behaviors and adaptations of ancient animals. 

Different Types of Coprolites

Coprolite specimens
Coprolite specimens | Image via Lori Carter from Pinterest

Fossilized excrements provide a window into the diets and behaviors of various kinds of organisms spanning multiple geological periods.

Expectedly, the shape, size, and characteristics of these fossils will vary based on the type of animal in question and the environment where it was fossilized. 

Coprolites can be classified based on their shape. 

These preserved remains can have a spiral, cylindrical, spherical, or irregular shape. 

The shape of the coprolite provides clues about the animal that produced it.

Greate white shark coprolite
Giant white Shark coprolite | James St. John via Wikimedia Commons

For instance, sharks and other fish produce spiral coprolites because they have a spiral-shaped intestine, while dinosaurs and mammals typically produce cylindrical coprolites. 

Coprolites also have varying textures based on the animals that produced them. 

The texture can be smooth, granular, or nodular. 

Herbivores usually produce smooth coprolites, while carnivores produce coprolites with a rough texture. 

It is difficult to tell the exact animal that produced a coprolite. 

A rough-textured coprolite
A rough-textured coprolite | Paul Starosta via GettyImages

Unless fossils of the animal’s body are found in the same location (which is very unlikely), we can only infer that the fossil came from a herbivore or a carnivore, as the case may be.

The environment in which coprolites fossilize also plays a vital role in what the coprolite looks like and how it will be preserved.

Coprolites preserved in waterlogged or anaerobic (low oxygen) environments tend to preserve more delicate details because they retain more organic materials. 

If the feces were deposited in an arid environment, the overall shape and structure of the coprolite are likely to be preserved. 

But most of the organic content will be lost. 

How Coprolites Are Discovered and Studied

Exploring fossilized remains through fieldwork | Daniel Balakov via iStock

Coprolites are discovered through careful fieldwork, where paleontologists scour sedimentary rock formations in search of potential fossil-bearing layers. 

However, in a few instances, people discover coprolites accidentally. 

Paleontologists on the field identify these fossilized feces based on their distinct shape and size. 

Sometimes, the remains may contain undigested food particles such as bone fragments or other remnants that are visible. 

Once a potential coprolite is found, it’s meticulously extracted from the rock where it was preserved and taken to a lab for further study.

Tools and Methods Used in Studying Coprolite Fossils

Archaeological tools
Skeleton and archaeological tools | LuFeeTheBear via iStock

Studying coprolite fossils to uncover clues about what the prehistoric animal that produced them ate involves using a range of tools and methods.

Some of the most important techniques for analyzing corporations include: 


Microscope in the Laboratory | Kkolosov via iStock

Scientists use high-powered microscopes to examine the composition and structure of coprolites. 

Thin sections can reveal microscopic details that are not visible to the naked eye. 

For instance, it might be possible to make out seeds, leaf remains, pollens, or bark by simply looking at the coprolites. 

However, magnifying these plants will reveal distinctive shapes and patterns, which can help identify the specific type of plant in question. 

Chemical Analysis

Chemical analysis
Chemical analysis in the laboratory | AnuchaCheechang via iStock

Chemical techniques like stable isotope analysis and trace element analysis provide insights into an organism’s diet.

Isotope ratios in coprolites can be used to determine whether an animal primarily consumed plants or animals.

Molecular Analysis

Molecular analysis
Molecular analysis | LaylaBird via iStock

In recent years, DNA analysis has become a powerful tool in coprolite studies. 

DNA extracted from coprolites can reveal not only the identity of the producer but also the specific species it consumed.

 X-ray Imaging

X-ray imaging | Pitchayanan Kongkaew via iStock

X-ray scans can be used to study the internal structure of coprolites, revealing hidden contents or structures without destroying the coprolite. 

Comparative Studies

Comparative studying
Comparative studying of fossils | sturti via iStock

By comparing coprolites to feces from known extant animals, researchers can make educated guesses about the identity and diet of the producers. 

Contributions of Coprolite Studies to Paleontology

Coprolites may not seem significant initially, but by employing various techniques, scientists can uncover valuable insights from them.  

Some of the things coprolites contribute to paleontology include: 

Understanding Animal Diet

Close up view of animal teeth in a skeletal jawbone | Natasa Ivancev via iStock

With body fossils, we can only speculate what an animal ate based on their dentition. 

Coprolites reveal the specific diets of ancient creatures, contributing to our understanding of prehistoric food chains and ecosystem dynamics.

Behavioral Reconstructions

animal behavior
Brown bear hunting with a catious behavior | DamianKuzdak via iStock

Coprolites offer clues about how animals hunted, foraged, and interacted with their environments and other species within their ecosystem.


Ancient forest ecosystem
Ancient forest ecosystem | vovashevchuk via iStock

Scientists can reconstruct the complex interactions that shaped ancient ecosystems by studying the fossils of animals found within the same area.

Evolutionary Studies

Concept of evolution | Macrovector via iStock

Coprolites provide a direct link for studying the behavior and adaptation of animals. 

This sheds some light on the evolution of feeding strategies across various geological periods.

Extraordinary Discoveries: Notable Coprolite Finds

Mary Anning
Portrait of Mary Anning | Mr. Grey via Wikipedia Public Domain

Amateur fossil collector, Mary Anning, discovered the first coprolites in the early 1800s. 

She theorized that the strange poop-shaped stones that she found in association with the ichthyosaurs and plesiosaurs she studied were fossilized poop. 

Mary Anning communicated her discovery to Paleontologist William Buckland, who studied these fossils and found that they contained remains of bones, fish scales, and other inclusions. 

In 1829, Buckland concluded that these were indeed dinosaur poop fossils and named them coprolites. 

Since then, there have been many more significant coprolite discoveries that have contributed to our understanding of the prehistoric animals that produced them. 

La Brea Tar Pits
La Brea Tar Pits | Daniel Schwen via Wikipedia CC BY-SA 2.5

The La Brea Tar Pits in Los Angeles, California, is one of the most famous fossil sites in the world and is known for its accumulation of ice-age animals. 

Coprolites from these animals have also been found at the site, providing scientists with information about their diet and behavior.

But coprolites don’t have to come from notable fossil sites like the La Brea Tar pits. 

The largest fossilized poop ever discovered was found on a private ranch near Buffalo, South Dakota. 

Barnum | Image via Poozeum

The coprolite, which has been nicknamed “Barnum,” is believed to have come from a T-rex since it was the only animal large enough to produce a poop of that size in that region.

While Barnum is famous for its size, many exceptional coprolites have been found containing well-preserved remains of prey animals, which makes them very valuable. 

For instance, coprolites associated with the Silesaurus, a dinosaur from the Late Triassic, were found to contain a high density of beetles. 

This was instrumental in determining the diet of this dinosaur. 

This is just one of several instances where partially digested remains of coprolites prove valuable for uncovering the diet of ancient animals.

The Stories They Tell: Coprolites in Ancient Environments

Fossil feces from a carnivorous dinosaur
Fossil feces from a carnivorous dinosaur | United States Geological Survey via Wikimedia Commons Public domain

In addition to contributing to our understanding of the diets of prehistoric creatures, coprolites can also provide clues about the environments where these creatures once thrived.

When paleontologists study coprolites, they can deduce the types of animals that live in a particular area and the nature of the ecosystem. 

The content of these coprolites will also reflect the availability of food sources, climate conditions, and even the geographical landscapes of these periods.

Ichthyosaurus coprolite | ilbusca via GettyImages

For instance, coprolites containing the remains of aquatic animals, such as fish scales or the shells of invertebrates probably came from an aquatic predator. 

Identifying the specific prey within the coprolites may also uncover insights about which part of the water column this prey hunted.

Similarly, coprolites rich in plant matter might suggest that the animal that produced the feces lived in a lush, vegetated environment. 

Coprolites from animals that lived in arid environments will be less rich and are likely to contain higher mineral content. 

Studying these types of fossils can also contribute to our understanding of how ancient organisms adapted to changes in the climate and landscapes where they lived.

Fascinating Uses of Coprolites Beyond Paleontology

Ichthyosaur coprolites
Ichthyosaur coprolites | James St. John via Wikimedia Commons CC-by-2.0

Although coprolites are most famously associated with paleontology, the value of these fossilized feces extends beyond understanding ancient ecosystems and animals. 

Coprolites have found various intriguing applications across fields like archaeology, medicine, and even understanding human history and health.

Coprolites from more recent times can provide insights into the dietary habits of ancient civilizations.

Researchers sometimes analyze coprolites found in archaeological sites in order to learn about the diet and food sources of past societies. 

These fossils can shed light on the culinary traditions, agricultural practices, and even food preparation methods of ancient civilizations. 

Lloyds Bank coprolite
Lloyds Bank coprolite | Linda Spashett via Wikipedia CC BY 2.5

Analyzing coprolites can also help archeologists uncover clues about the cultural practices of ancient societies, including their use of medicinal plants or substances and how they managed or disposed of waste. 

In some cases, they’ve revealed evidence of parasites, bacterial infections, and dietary deficiencies, offering clues about the health challenges our ancestors faced.

Due to their unique composition, coprolites were once considered a rich source of phosphates, making coprolite mining very popular in the 1800s. 

Rev John Stevens Henslow, who was a professor of Botany at St John’s College, Cambridge, made this discovery in 1842, which kickstarted a mining frenzy for coprolite on an industrial scale throughout East England. 

The phosphate extracted was mainly used for producing fertilizer and also for munitions after the First World War. 


Coprolites are valuable but little-known treasures that provide direct evidence of what creatures consumed in ancient ecosystems. 

This makes them very important to paleontologists looking to unravel the dietary preferences of ancient animals. 

It is also a useful tool for reconstructing ancient ecosystems and the intricate food chains that existed within them. 

By studying these trace fossils using advanced techniques such as microscopy, x-rays, and chemical analysis, we can learn more about the life of ancient organisms, their interactions with other animals, and their ecosystem in general.


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