If we relied on our sense of smell to outrun a predator it would be on top of us before we were able to get out of the way. 

Smell is a slow sense. Our brains have evolved so that our 'fight or flight' response is linked more strongly to sight and sound. However what if it were smell?

You are flying (yes flying, why not? It's our imagination) you're flying, this is an experience guided by instinctual responses, you've turned into a creature without eyes and ears, you can feel the air  on your skin, temperature and atmosphere to guide you, but your main sense is smell. 

As you breathe in you catch a scent, it drifts in and out of your nostrils. 

You begin to concentrate on the task of understanding what the scent is. You sense on the in breath, drawing the scent in. It is lost on the out breath. Repeat. 

It takes some time. The aroma disappears so you circle back to try to pick it up again. Breathing in hungrily (the same way you do when you fill up the car with petrol, mmm petrol smell....just me?)

With no other senses to help make a quick identification, you hone in and concentrate on what this scent is. 

Living or elemental?

Moving or still?

Opportunity or threat?

This takes quite a lot of brain power and a thoroughly logical process of elimination based on years of fragrance experience. You summon the inner workings of your olfactory memory, a vast catalogue of sniffs, whiffs, squirts and wafts learned from years of interacting and being one with the environment. Every known note, vapour, oil, evaporation, grease, excretion and emission contributing to a different sort of 'minds eye' and slowly and gradually answering the questions 'what is this I smell?' and 'what should my response be?'.

At this point you've had to land on a large tree branch to sort out your scented memories and formulate an interaction in response. 

Still breathing and smelling, you arrive at a conclusion. An answer has emerged from the networked paths of aromatic associations. You breathe in once more to check your conclusion and test your assertion. 

What do you smell?

...Touch here                     Taste here...