Entity: Longsnout Rat

Source Player Core 2 pg. 29 ^1.1

Your long snout gives you a keener sense of smell than most ratfolk. You gain imprecise scent with a range of 30 feet. This means you can use your sense of smell to determine a creature's location. 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 to Seek a creature or object within the range of your scent.