Episode 59: Smell

Comparisons

Humans, while possessing excellent color vision, have a relatively poor sense of smell compared to many animals. James Fodor explains that most mammals, unlike birds, have a keen olfactory sense, with dogs being able to detect concentrations of odorants 100,000 times lower than humans 1. This remarkable sensitivity is tested by gradually reducing odorant concentrations until they become undetectable.

It's very important to understand what they mean. The way they test this is basically by repeatedly reducing the concentration of an odorant molecule and seeing if the animal or the human can detect it.

--- James Fodor

Fodor also notes that aquatic animals often combine taste and smell into a single chemical sense, highlighting the diversity of olfactory capabilities across species 2.

   

Bloodhounds

Bloodhounds are renowned for their extraordinary olfactory abilities, capable of detecting scent trails from just a few cells. James Fodor highlights that these dogs have nasal chambers with about 4 billion receptor cells, vastly outnumbering the 5 to 6 million found in humans 3. This allows them to follow trails that are several days old, even across challenging terrains.

They have noses that are some ten to 100 million times more sensitive than humans.

--- James Fodor

Their exceptional scent detection is a result of both their dense concentration of olfactory receptor neurons and rigorous training, making them invaluable in police work and other fields 1.