Footprints are a kind of evidence of behavior often called a 'trace fossil' - geological evidence of biological activity. This is in contrast to 'body fossils', fossilized remains from organisms' bodies.

Scientists can learn a lot from sites where human footprints have been found, including:

• Estimates of height, weight, and gait of the humans who made the footprints - which also tells us how many people made the footprints.
• Features of the substrate that the footprints were formed in (was it soft? hard? wet? dry?).
• Aspects of the environment that the humans who made the footprints were living in, especially if there are footprints left by other animals.

Several human footprints sites have been discovered; you can explore the evidence from some of them here.