A trace fossil preserves evidence of ancient behavior, such as footprints or burrows. Instead of preserving the organism’s body, it records an activity that the organism performed while alive.
Examples include dinosaur trackways, animal burrows, feeding marks, borings, crawling trails, root cavities, and fossilized droppings called coprolites. The scientific study of trace fossils is called ichnology. Because these fossils record behavior, they can reveal how an animal moved, fed, rested, or interacted with its surroundings.
Trace fossils are commonly confused with molds and casts. A mold is an impression left when an organism or part of one is buried and later removed; a cast forms when that impression is filled with minerals or sediment. A body fossil, by contrast, preserves physical remains such as bones, teeth, shells, or leaves. Trace fossils can be especially valuable for reconstructing ancient environments because they usually form where the activity occurred, rather than being transported after death.