The general term for a fossil recording an organism’s activity, such as a burrow or track, is a trace fossil. It is also called an ichnofossil.
Unlike a body fossil, which preserves part of an organism’s body, a trace fossil preserves evidence of what an organism did. Examples include footprints, trackways, burrows, feeding marks, borings, root cavities, and fossilized droppings called coprolites. The scientific study of these traces is known as ichnology.
Trace fossils are especially valuable because they can reveal behavior and environment. A footprint may show how an animal moved, while a burrow can indicate that an organism lived or sought shelter in particular sediment. Because traces usually form where the activity occurred, they may provide more direct evidence of an ancient habitat than a transported body fossil.
The main distinction is simple: a fossilized bone, shell, or leaf is a body fossil; a track, tunnel, bite mark, or nest is a trace fossil. A mold fossil records the shape left by an organism, while a compression fossil preserves an impression or flattened remains.