Sensate Gnome
Source Pathfinder Player Core
You see all colors as brighter, hear all sounds as richer, and especially smell all scents with incredible detail. You gain a special sense: imprecise scent with a range of 30 feet. This means you can use your sense of smell to determine the exact location of a creature. The GM will usually double the range if you're downwind from the creature or halve the range if you're upwind.
In addition, you gain a +2 circumstance bonus to Perception checks whenever you're trying to locate an undetected creature that is within the range of your scent.