Checking out who has the best sense of smell is quite a complex issue. In human bodies, we suck up air through the nose, and “odorants” (the posh word for scent particles) stick to scent receptors that are housed there.
Information is then pushed up into the brain, into a special region called the olfactory bulb. The whole thing is a bit of a mystery, but current thinking is that it acts like a processing unit, taking in information from the scent receptors, packaging it all up in data packets, and then shoving that out for the rest of the brain to analyse and interpret.
Although we’re learning more and more about brain functions, a lot of it is still theory. This means scientists are having a lovely time arguing over what might be happening.
When it comes to animals, the story is even wilder.
Snakes are like cats in that they have noses and a Jacobson’s organ. However, they also have scent receptors on their tongues. They go about with their tongues out, loading up on odorants, and then sucking them up into their mouths, pressing them right into the Jacobson’s organ.
Flies and butterflies have scent receptors on their feet. When they land on something, they can tell instantly if something is edible or poisonous. Octopuses are similar, in that their scent receptors are in the suckers that line their legs.
Honeybees have scent receptors on their antennae, so they wave these about, capturing odorants in the air. They also have special sensory organs called palps on the sides of their mouths that are covered with scent receptors.
But the poster animal for amazing places you might have scent receptors is the yellow bullhead catfish. It lives in north American pools and rivers that are so dark and sludgy, that it has taste receptors all over it’s body, from nose to tail. Scientists think this adaptation occurred so it can smell its way around because it’s simply too dark to see.