Just for informational purposes here's some info for everyone:

Characrteristics of mountain lion versus dog tracks:

Mountain Lion
1. Claw markes generally absent. If present, they will be sharp and narrow.
2. Four tear-drop shaped toes, grouped asymetrically.
3. Trapaziodal shaped heel pad.
4. Three lobed heel pad with two indentations along rear margin.

Dog
1. Toenail prints generally present will be blunt and broad.
2. Four round shaped toes grouped symetrically.
3. Triangular shaped heel pad.
4. Heel pad lacks distinct indentations and three lobed appearance.

See also:
http://www.bigcats.org/abc/identification/pumadogtracks.html