Synthetic Trace Fossils using mechanical bugs

Clint Cowan, Carleton College
Author Profile


This activity is suitable for either an hour-long in class activity or a longer laboratory. It explores trace fossils by creating tracks in various substrates using mechanical bugs (Hexbugs). Students analyze the traces without seeing how they were made, then get to explore the traces by playing with the mechanical bugs that made them and varying the substrate.

Used this activity? Share your experiences and modifications



Undergraduate course in Paleobiology (200-level). Mostly Geology majors, some Biology and undecided.

Skills and concepts that students must have mastered

This activity can be used to introduce trace fossils or after the basics have been taught.

How the activity is situated in the course

Presently it is an in-class exercise, with a quick set of notes that the students hand in.


Content/concepts goals for this activity

Analysis of trace fossils: biomechanics, behavior, etc.

Higher order thinking skills goals for this activity

The student apply careful observation of small details to infer (interpret) the biomechanical mechanisms by which traces were made, and suggest possible behaviors the traces represent (locomotion, grazing, etc.)

Other skills goals for this activity

working in groups

Description and Teaching Materials

I lay out butcher paper on our lab tables, and sieve sand into a smooth area approx 3x4 feet in size, and about 1/4" of sand deep. I then take a variety of Hexbugs ( and walk them across the sand (each table gets a different bug or set of bugs). The students do not see this part. The students then analyze the tracks.

Teaching Notes and Tips

I make the tracks before the students arrive. They then work in teams of 3 - 5 students to make sketches, analyze and hypothesize what made the traces (and how they made them). What motions are evident? What parts of the creature were in contact with the substrate? What behavior is indicated?


The students hand in a sheet of analysis: sketches, interpretation of motion, etc.

References and Resources