Rusty's Nose

Nathan comments that a dog's sense of smell 150x humans so I investigate : turns out, it is 1000x more sensitive than ours. In fact, a dog has more than 220 million olfactory receptors in its nose, while us humans have about 5 million. So sensitive is a pooch's snout that it can, when trained, detect an early stage tumor in the human body. For his part, Rusty has never missed a dropped kibble nor best mate's ass.