A recent stomach flu forced me into a 48 hour span where I didn't eat anything and drank little. By the second morning I was exhausted, still mostly nauseous, but starving.
I started to make my way downstairs. By the second step I could clearly smell a wheat bread toast, recently toasted, somewhere downstairs. This is quite unusual for me as I have a weak sense of smell.
It occurred to me that animals' superior sense of smell is not simply a matter of better sensors, but also a matter of hunger. A bear can smell your food from a mile away probably because he's very hungry. In the same situation I'd probably have an order of magnitude improved senses as well.
I recently watched Into the Wild so man and nature are on my mind.