Came upon a mountain lion track while hiking near Del Valle Reservoir last week. It had been raining and the ground was nearly saturated, good conditions for seeing tracks.
I was looking at a variety of tracks when I came upon a set of mountain lions prints. I photographed one the clearest tracks with my iPhone camera. Here it is.

The mountain lion track is more round than oval and the claws don't show, unless the lion slips or needs traction. When the lion slips, it will involuntarily extend its claws and they will show as points in the mud.
The heel pad of a lion appears larger than a coyote or other canine.
Here’s a good example of a coyote track.

The coyote track is more oval and the claws show clearly in the track. The heel pad does not appear as large.
The mature coyote track is smaller than the mature lion track. Large domestic dogs often leave tracks as large as lion tracks and sometimes it can be difficult to distinguish between the two. In the case of this lion, I would give the ID a high degree of confidence.

What a great read about mountain lions tracks and coyotes. The difference and the pics were awesome. I hope I never see either at http://www.peartreegameranch.com my stomping grounds. If I did see a mountain lion, I would shoot first and run second. In case I missed. ha ha