concept

Trace fossil

A mark an organism left in sediment rather than the organism itself: footprints, trails, dwelling burrows, borings, fossilised dung, bite marks, nests. They carry three advantages body fossils do not - they are almost never transported away from where they formed, they survive in high-energy settings where bone mineral dissolves, and they record *behaviour*: gait, speed, social life. No skeleton can tell you any of that.