Trace Fossils
Behaviour preserved in stone — tracks, burrows, feeding traces, and resting marks documenting ancient life without a single body fossil.
Overview
Trace fossils (ichnofossils) are not remains of bodies but records of behaviour: tracks, trails, burrows, borings, bite marks and coprolites. They capture living animals in action and are often the only record of soft-bodied or elusive species.
Quick Facts
Key Characteristics
- •Tracks and trackways — locomotion, speed and limb posture (dinosaur and tetrapod footprints)
- •Burrows (domichnia) — dwelling structures recording sediment oxygenation
- •Feeding traces (fodinichnia, grazing trails) — how animals harvested the seafloor
- •Resting traces — impressions left in one place (like Asteriacites starfish resting marks)
- •Coprolites and regurgitalites — fossil dung and feeding residue preserving diet
Fossil Record
Traces form only in place — they cannot be washed elsewhere — making them superb indicators of original sediment conditions. Famous sites include the Coconino and dune-sandstone tetrapod trackways, dinosaur track beds of the Connecticut Valley and Dinosaur Ridge, and deep-sea core burrow records.
Global Distribution
Worldwide, in nearly all sedimentary environments from river bars to abyssal plain.
Evolutionary & Scientific Importance
Ichnology documents behaviour, the timing of major evolutionary events (the first land-walking trackways predate body fossils by tens of millions of years), and — through bioturbation intensity — the oxygenation of ancient oceans.
Classification
Because the maker is usually unknown, trace fossils carry their own names — the same ichnogenus can be made by different animals over time.