BBC Earth

Facts about smell

Beyond Human
  • In cold environments it’s harder for scents to evaporate into the atmosphere, which is why the air smells a lot cleaner. Wolverines, which live in the frozen wilderness, have acute noses and can sniff out tiny scents from more than 1km (0.62 miles) away. Our human scent detectors would be the size of a ten pence piece if unravelled. A wolverine’s would be the size of a plate.

  • For the rattlesnake, its sense of taste and smell are the same thing – it uses its tongue to detect scent molecules in the air, which it then presses onto its sensory pad called a Jacobson’s organ. When it bites its prey, it immediately lets go so as not to damage its fragile fangs. In the venom are molecules called disintegrins, which act as a sensory tag so the rattlesnake can then track their prey once the venom has had time to take effect.

  • Sharks are renowned for detecting the smell of human blood, but just how true is this? Despite the myth, there is no evidence that sharks detect and seek out human blood. But is there one smell that all sharks detest and are hard-wired to flee. It’s called a necromone – a chemical that tells sharks there is a predator in the area. It’s also the smell of dead shark, another sure sign there’s danger about.

  • Bees detect scent with their antennae. They also use pheromones to communicate and have a language of over 15 pheromones that trigger different behaviours.

  • Moths are one of the planet’s best smellers and pick up scent with their sensitive antennae. Some species can pick up scents from nearly 5km (3 miles) away.

  • A striped skunk uses odour to protect itself. Its scent is made of seven volatile compounds and the reason we find it so offensive, is because their scent contains sulphur-containing chemicals, called thiols. It’s so potent that it can cause temporary blindness if it hits the eyes.