Male ring-tailed lemurs (Lemur catta) appear to make themselves more attractive to females by secreting a fruity and floral aroma from their wrists. 

That’s more than just a fun fact. If it’s right, it marks the first time that pheromones have been identified in a primate.

“During the yearly breeding season, male lemurs rub the glands on their wrists against their fluffy tails and then wave them at females in a behaviour called ‘stink flirting’,” says Kazushige Touhara from the University of Tokyo, who led a recent study.

He and colleagues also discovered that the scent is caused by three compounds that previously have been suggested to be involved in the recognition of newborn sheep by their mothers. One also is known as a sex pheromone in some insect species.

To make their findings, which are presented in the journal Cell Biology, the researchers tracked the behaviour of a conspiracy of ring-tailed lemurs (as in a group, not a secret plan) at the Japanese Monkey Centre in Aichi and the Research Institute of Evolutionary Biology in Tokyo.

They observed that females sniffed the scent markings left by males more often and for longer periods during the breeding season. 

When they specifically isolated the perfume from four males and presented it to females individually, the females sniffed the fruity-smelling odour for roughly twice as long as the bitter-smelling gland secretions produced off-season.

But it’s an age thing. The researchers found that young, sexually mature males produce more of the compounds than older males and that females past their reproductive prime are altogether unimpressed by the odours males exude. 

Using gas chromatography-mass spectrometry analysis on the wrist-gland secretions produced during breeding and non-breeding seasons, Touhara determined the major chemical components making up the male scents. 

Three aldehyde compounds – dodecanal, 12-methyltridecanal and tetradecanal – were present in both odours but showed substantially higher concentrations during the breeding season. 

Moreover, when the compounds were individually presented to females, only the mixture of all three had a significant ability to hold their attention.

It the first time 12-methyltridecanal has been identified in primate species.

The researchers say the findings suggest the three compounds are, indeed, pheromones, but more work is required to determine whether they directly influence sexual behaviour.