There are bite marks on the shit. Who is so hungry?

If we want to peek into the mysteries left by ancient life, we can't miss any clues, even their excrement . Maybe you will find it incredible, but there is actually a special term to describe this extraordinary prehistoric biological remains, that is - coprolite .

Various coprolites | Adrian P. Hunt / Vertebrate Coprolites. New Mexico Museum of Natural History & Science, Bulletin (2012)

"Poop" from ancient times

As the name suggests, coprolite refers to "the excrement of prehistoric animals in a fossilized state." In a more common context, it is also called fecal stone or dung ball. This concept was first proposed and formally described by British paleontologist William Buckland in 1892. In terms of classification, it belongs to the category of biological relic fossils, just like footprint fossils (usually the "animal" here refers to vertebrates).

In most cases, the color of coprolites ranges from light yellow to dark brown, and they appear cigar-like or long stick-shaped , but there are exceptions such as spiral coprolites. Because they contain a large amount of calcium phosphate, coprolites are more compact and dense in texture than other ordinary fossils.

Spiral fish coprolites | Paul Rummy et al. / Scientific Reports (2021)

So, how did these unremarkable "poop" from ancient times come into the public eye?

Back in 1824, the famous fossil hunter and paleontologist Mary Anning discovered the fossil of the Mesozoic marine reptile ichthyosaur for the first time in Lyme Regis in southern England. In the process of cleaning the fossil fragments, she was puzzled to find that there were always some small stones similar to bezoar stones appearing in the abdominal area of ​​the ichthyosaur skeleton. Fish scales and fish bone fragments could be seen in some of the broken stones, and there were obvious signs of erosion on the surface of these bones.

She then recorded her discovery in detail, which attracted the attention of William Buckland, an authoritative geologist at the time, five years later. After a series of studies and comparisons, he finally officially named this peculiar little stone "coprolite" .

Classifying Coprolites by Shape | Adrian P. Hunt & Spencer G. Lucas / Vertebrate Coprolites. New Mexico Museum of Natural History & Science, Bulletin (2012)

The "convenience" of the "prehistoric overlord"

There may be no eternal species in the torrent of life evolution, but even if their physical bodies have long disappeared, they will definitely leave traces of their existence, and coprolites are such an alternative representative.

With the help of inconspicuous fecal fossils, scientists can restore many details of these ancient creatures, such as: Is this animal herbivorous or carnivorous ? How big can it grow? The growth rate, and even the ancient geographical ecological environment at that time... It can be seen that these seemingly inconspicuous "fecal balls" actually have unexpectedly important scientific research value in studying the evolution of a species.

Coprolite with bite marks (this is a foodie with a story to tell) | Poozeum / Wikimedia Commons

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Generally speaking, we have no way of knowing who bit the coprolites with tooth marks on them... because the perpetrators are embarrassed to say that the evidence is limited. However, there are occasional exceptions. For example, as mentioned in this article, by comparing fossil teeth unearthed from the same era and location, we can be sure that some of the tooth marks on the feces were caused by shark bites, and even shark teeth have been found in the coprolites, helping us to "identify the identity."

Take the dinosaurs that we are most familiar with, for example. By analyzing the food residues left in thousands of coprolites, we can not only know what these prehistoric beasts ate for their last "dinner", but also restore their daily food sources and composition, and further deduce the species distribution and natural environment in the area. And because some minerals in coprolites can be preserved more stably than bone fossils , by analyzing the specific mineral content in them, we can more accurately understand the living habits of the species.

For example, among the dinosaur coprolites found in many places in North America, some of them are about twice as large and numerous as other specimens in the region! The proportion of bone fragments contained in these coprolites is as high as 30-50%. It is inferred that the owner of these coprolites was some kind of large carnivorous theropod dinosaur, which was the most terrifying top predator on land at that time - Tyrannosaurus Rex .

Tyrannosaurus coprolites containing bone fragments | Karen Chin et al. / Nature (1998)

Compared with omnivores and herbivores: carnivores need to digest more meat and bones, so they need stronger stomach acid to break down these foods. The stomach acid and proteolytic enzymes of carnivores of different sizes and types have different degrees of erosion and digestion of bones. By further analyzing the hidden information contained in these fecal fossils, we can know whether these animals have digestive tract diseases or other pathological reasons that led to their death, and even infer the population size of the species within a certain range.

Let's take another example. Silesaurus is a dinosauroid that lived 230 million years ago in the Carnian period of the Late Triassic. Its fossils are widely found in Poland. As a primitive basal dinosauroid, studying the living habits of Silesaurus will help to reveal many mysteries in the evolution of dinosaurs.

Insect remains in the feces of Siliosaurus | Martin Qvarnström et al. / Current biology: CB (2021)

In a study of the coprolites of Siliosaurus, scientists found that there was a high density of beetle remains in their coprolites, and combined with the special beak-shaped snout development characteristics, there is sufficient evidence to infer that Siliosaurus was an insectivorous animal that mainly fed on insects. Since they are closely related to the ancestors of dinosaurs, there is reason to believe that the primitive dinosaurs should also be a group of small bipedal running insectivorous animals similar to Siliosaurus.

The poop that powered the Industrial Revolution

But another reason why coprolites have attracted worldwide attention is actually the huge commercial value they contain.

In 1842, Felix Kstowe, a professor of botany at St John's College, Cambridge University, England, discovered after studying the chemical composition of coprolites that a large amount of phosphate could be extracted by processing coprolites with sulfuric acid. He then applied for a patent for this discovery and soon put it into practice.

Coprolite | James St. John / Wikimedia Commons

With the rapid economic growth after the Industrial Revolution in Britain, a large number of coprolites were mined and used to refine phosphate to meet the needs of industrial production. The mining of coprolites gradually formed an industry and led to the prosperity of port trade in southern England until it gradually declined around 1880. These creatures billions of years ago would never have thought that their excrement would actually promote the leap of human civilization in later generations. Perhaps this is a kind of reincarnation of life.

Why are we so fascinated by these coprolites? Perhaps it is because they allow humans to have a magical connection with prehistoric animals. This sense of novelty is not just because we know what was on the menu of Tyrannosaurus Rex, but more because we can feel the rhythm of another creature's pulse through the barriers of time.

This article comes from the Species Calendar, welcome to forward