The human imagination is pretty limited when it comes to animal senses. We call people with good vision "eagle eye," and believe that toucan's can smell cereal because they have big noses. It turns out the animal kingdom has plenty of creatures whose senses go beyond what we can conceive without our head exploding. For instance ...
7Silvertip Grizzlies Can Smell You From 18 Miles Away (And Across Time)
Humans use smell to get us excited about pie before we actually put it in our mouths, and not much else. Our superheroes have X-ray vision and super hearing, but the ability to sniff out clues is usually left to cartoon dogs. But that's just because we can't imagine what the world smells like to a bloodhound. When we walk down the street, our senses tell us who's doing what at that moment, and which one of them smells like urine. A bloodhound's nose allows it to perceive that same street across time.
His nose is a time-traveler.
It knows who walked down the street last night at 11PM, what the soles of their shoes were made of, the brand of cigarette they were smoking. Your eyes see this...
... and tell you Ingrid had a secret admirer last spring when they fixed the sidewalk. Your dog knows Ingrid is buried under there and that you shouldn't turn your back on the doorman who smokes Pall-Malls.
Fortunately for the sake of this article, and unfortunately for the sake of everyone who's afraid of bears, the silvertip grizzly's sense of smell is seven times stronger than that of the bloodhound.
Known to the Japanese as a blood-murdering cuddle-monster.
You see, silvertips can smell your fear, just like any other scary-ass predator. But unlike most predators, they can smell your fear over distances measured in double digits. In miles. These bears can smell a carcass from 18 miles away. When a silvertip enters a clearing, you're screwed even if you left 48 hours before. And if you're still there, all that sweating, pissing yourself and crapping your pants while you ran away will be laying down a neon-colored trail for the bear to follow until you get tired.
Part of the reason for this is because, despite what some scientists would have you believe, predators are scavengers as well, and the ability to smell a dead body close to 20 miles away goes a long way toward helping get a free meal. Since bears scare the shit out of every other living thing (except maybe wolverines), being able to smell someone else's kill is like being a 250-pound bully in eighth grade; no one is going to fuck with you when you walk up to him and take his food. Not even entire packs of wolves.
Being a gigantic bear is nature's way of saying, "Fuck off!"