Because there is some overlap between different senses, different methods of neurological classification can yield as many as 21 senses. And this number does not include some physiological experiences such as, for instance, the sensation of hunger or thirst.

By far the most important organs of sense are our eyes. We perceive up to 80% of all impressions by means of our sight. And if other senses such as taste or smell stop working, it’s the eyes that best protect us from danger.

You’ve probably been taught that humans have five senses: taste, smell, vision, hearing, and touch. However, an under-appreciated “sixth sense,” called proprioception, allows us to keep track of where our body parts are in space.

It doesn’t take much reflection to figure out that humans possess more than the five “classical” senses of sight, hearing, taste, smell, and touch. Because when you start counting sense organs, you get to six right away: the eyes, ears, nose, tongue, skin, and the vestibular system.

This sense is called proprioception (pronounced “pro-pree-o-ception”); it’s an awareness of where our limbs are and how our bodies are positioned in space. And like the other senses — vision, hearing, and so on — it helps our brains navigate the world. Scientists sometimes refer to it as our “sixth sense.”

Smell

Consequently, humans can distinguish between a vast number of scents. We can even track scent trails, provided it’s the right odor. We actually outperform dogs on some scents, like certain aromatic molecules in coffee. And, indeed, we can smell blood.

Neuroscientists have suggested that this close physical connection between the regions of the brain linked to memory, emotion, and our sense of smell may explain why our brain learns to associate smells with certain emotional memories.

The human nose can detect one trillion different odours, far more than we previously thought, say US scientists.