Scent is a specialized facet of Perception concerned solely with the sense of smell—the capacity to detect, distinguish, and follow odors carried on the air. In most people it is a modest sense, easily overlooked, but among animals it is often the sharpest gate to the world, keener by far than sight or hearing. A strong Scent lets its bearer read the recent history of a place, tell one creature from another by smell alone, and follow a trail long after the eye has lost it—reaching, at its heights, across miles of open air or water.
Anosmic
The anosmic have essentially no functional sense of smell. Only the most overpowering odors reach them—smoke thick enough to choke, rot pressed close to the face—and even those register dimly, if at all. They cannot track by scent, cannot tell one person or beast from another by smell, and miss the warnings a nose would otherwise give of spoiled food, gas, or fire. Some are born this way; injury, illness, or age brings others to it.
Dull
A dull sense of smell is blunt and short-ranged. Strong, near odors register plainly—a cook-fire, a midden, a rain-soaked field—but faint or distant ones slip past unnoticed. Those so endowed cannot follow a trail or pick a single scent out of a crowded room, and they lose most smells the moment the wind shifts. This is the low end of ordinary humanity.
Common
Common scent is the everyday human range. It distinguishes familiar smells readily—bread, smoke, a known person close at hand—and notices a strong change in the air. It cannot track in any useful way and loses faint odors quickly to wind and distance, but it serves well enough for cooking, for judging spoilage, and for the small warnings of daily life. Most people live here.
Keen
A keen nose is notably sharp. It picks out individual odors from a mingled mess and catches what others miss—food turning before it visibly spoils, a stranger’s lingering presence in a room lately left, the smell of coming rain. Skilled hunters and trackers, some cooks and vintners, and many common animals hunt here. Such a nose can follow a fresh, strong trail over short distance with effort.
Acute
Acute scent is a true scent-hunter’s gift. Its bearer can run a trail hours old across open ground, tell individuals apart by smell alone, and read the recent comings and goings of a place from the air still hanging within it. This is the register of hounds and hunting-dogs, and of the rare human whose nose rivals them. Distance and passing time no longer easily erase a scent from their reach.
Preternatural
A preternatural sense of smell seems to reach beyond the body itself. It follows a cold trail a day or more old, detects prey, water, carrion, or fire from great distance downwind, and teases a single thread of scent out of a hundred tangled together. Bears, wolves, and boar range here—an animal that catches the smell of a carcass or a campfire from miles off and comes to it unerringly, across country it has never crossed.
Uncanny
Uncanny scent is smell raised nearly to prophecy. Its bearer detects traces so faint as to seem impossible—a few drops of blood diffused through miles of water, a lone creature moving far downwind, a shift in the world carried on the air long before it arrives. Sharks and a handful of legendary beasts live in this register; to them the surrounding land and sea are an open book written in smell, and almost nothing living can approach unannounced.
In Practice
A stag, wounded in the flank, crosses a clearing an hour before dawn. The anosmic creature passes the same ground later and knows nothing of it. The dull-nosed one catches the blood only by standing in the trampled grass. The common nose registers a faint copper tang and thinks no more of it. The keen-nosed hunter reads it at once as a fresh, hurt animal and guesses which way it fled. The acute hound simply has the trail, and runs it down through the trees. The preternatural bear smells the wound from a mile downwind and turns toward it without hesitation. And were a drop of that blood to reach the sea, the uncanny shark would find it diffused through miles of dark water, as plain to it as a lantern held up in the night.