Coprolites are fossilized feces, classified as trace fossils because they preserve evidence of an organism’s activities rather than its physical body. By studying these preserved remnants, scientists gain direct insights into the deep past, uncovering details about extinct animals and their environments. They allow researchers to reconstruct the behaviors and biological conditions of creatures that roamed the Earth millions of years ago.
Formation and Identification of Coprolites
The transformation of organic waste into stone involves a process called permineralization. This occurs when minerals, such as calcium phosphate, silica, or calcium carbonate, gradually replace the original organic material, preserving the structure over millions of years. Carnivore coprolites often show calcium phosphate replacement due to high phosphorus content from bones, while herbivore coprolites commonly permineralize with silica or calcium carbonate.
Paleontologists identify coprolites by examining their shapes and surface textures. Spiral forms often indicate the waste of ancient sharks or certain fish, reflecting their intestinal structure. Other carnivore coprolites are commonly cylindrical, spheroidal, or rod-like, sometimes exhibiting pinched ends or longitudinal striations. The context of discovery, such as proximity to skeletal remains or within a known prehistoric habitat, also provides clues about the animal that produced them.
Reconstructing Ancient Diets and Ecosystems
Coprolites provide direct evidence of what ancient animals consumed, offering insights into prehistoric food webs. Visible inclusions within fossilized feces reveal dietary habits; the presence of crushed bone fragments, scales, or teeth points to a carnivorous diet. A large coprolite from Canada, measuring 44 cm long, contained bone fragments, suggesting it belonged to a giant carnivore like a Tyrannosaurus rex. Conversely, indigestible plant fibers, seeds, wood particles, or pollen within coprolites indicate an herbivorous diet.
Analyzing microscopic plant components, such as pollen grains and spores, allows scientists to reconstruct ancient ecosystems and vegetation. Pollen assemblages can indicate whether the prehistoric environment was a wetland, forest, or grassland. Studies of Early Cretaceous coprolites from Spain revealed abundant plant remains, pollen from cypress and extinct conifers, and charcoal, suggesting a continental wetland environment where wildfires were common. Coprolites from the Late Permian of Russia have also revealed diverse organic inclusions, including plant cuticles, wood fragments, and spores, painting a detailed picture of the ancient flora.
Clues to Prehistoric Animal Health
Beyond diet, coprolites offer insights into the health of ancient animals. The discovery of parasite eggs and larvae within these fossilized remains provides direct evidence of prehistoric diseases and parasitic infections. The eggs of whipworm (Trichuris trichiura) were found in the colonic contents of an Inca mummy, providing early evidence for ancient parasites. Investigations of Neolithic coprolites from Durrington Walls, England, revealed fish tapeworm eggs in dog feces, indicating the consumption of raw or undercooked fish, and capillariid nematode eggs, suggesting the ingestion of internal organs from infected animals.
Chemical analysis of coprolite composition reveals aspects of an animal’s digestive system and metabolism. Researchers use methods like lipid biomarker analysis to determine the likely species that produced the coprolite, comparing lipid profiles to established values for different animals. This analysis can confirm the origin of the fossilized feces, distinguishing between human and dog remains, for example. Such detailed examination provides an understanding of the biological conditions and ailments affecting ancient creatures.