Is it possible to smell weakness? Scientists reveal furry creature that can

29 Jun 2018

A very, very grumpy ring-tailed lemur. Image: Luc Sesselle/Shutterstock

We often hear about being able to smell fear but, for ring-tailed lemurs, weakness has a distinctive scent, as new research shows.

The law of the jungle pushes the idea that only the strongest can survive and, when it comes to figuring out who is the weakest out there, the ring-tailed lemur appears to have a major advantage.

In a paper published to Scientific Reports, a team from Duke University in the US discovered that the furry primate found in Madagascar is able to tell a fellow lemur is weaker by the natural scents they leave behind. It appears that the males tend to act more aggressively towards lemurs that are physically injured because the scent signature is dampened. In fact, tests showed that male lemurs were more aggressive to an inanimate rod covered in the injured lemur’s scent than one with a healthy scent.

In general, body odour plays a major part in how the creatures react with one another, with both males and females having potent scent glands on their genitals which secrete a foul-smelling substance – to human noses, at least.

When the lemurs smear their smelly secretions on twigs and branches in their territory, up to 300 different chemicals are left behind to tell other lemurs that they were there and that they are possibly ready to mate.

‘Any opportunity to climb the social ladder’

To find out whether they could detect weakness, between 2007 and 2016, the team collected scent secretions from 23 lemurs based in a nearby park while they were receiving treatment for wounds or other injuries shortly after they happened.

The ring-tailed lemur is used to fighting for dominance in the wild resulting in them usually being covered in bite marks and missing tufts of fur.

Using gas chromatography-mass spectrometry, the team was able to see how injury changed the chemical makeup of the scent, with the number of compounds decreasing by 10pc.

The scent was especially muted during the mating season, when fights are more common, and the reduced compounds even persisted after the injured lemurs were treated with antibiotics.

“They respond more competitively when they could easily have the upper hand,” said Christine Drea of the research team. “These animals constantly monitor the physical condition of their competitors and respond quickly to any opportunity to climb the social ladder.”

Colm Gorey was a senior journalist with Silicon Republic