Source: Player's Handbook
You can follow the trails of creatures and characters across most types of terrain.
Benefit: To find tracks or to follow them for 1 mile requires a Survival check. You must make another Survival check every time the tracks become difficult to follow, such as when other tracks cross them or when the tracks backtrack and diverge.
You move at half your normal speed (or at your normal speed with a -5 penalty on the check). The DC depends on the surface and the prevailing conditions: see Tracking).
Special: A ranger receives Track as a bonus feat. He need not select it.
This feat does not allow you to find or follow the tracks of a subject of a pass without trace spell.
Normal: Without this feat, you can use the Survival skill to find tracks, but you can follow them only if the DC for the task is 10 or lower. Alternatively, you can use the Search skill to find a footprint or similar sign of a creature's passage using the DCs given above, but you can't use Search to follow tracks, even if someone else has already found them.