For ring-tail lemurs, there’s no need to pop down to the drug store to pick up an alluring scent before a date. A recent paper published in the journal Current Biology details how male ring-tail lemurs make themselves more appealing to females with the help of a scent gland on their wrist.
Ring-tail lemurs are a large strepsirrhine primate endemic to Madagascar. Like humans, they’re active in the day and sleep at night and, like humans, they’ve gotta work to impress a mate (and make friends).
During the annual breeding season, male lemurs are believed to catch the eye of female lemurs by rubbing the glands on their wrists against their fluffy tails and then waving them at females in a behavior called "stink flirting". And, according to a team of researchers in Japan, it doesn't smell half bad, "Usually, sex pheromones utilized in wild animals tend to smell bad or animalic to humans, but we are surprised that the identified odors in this study smell relatively good to humans (fruity and floral)," senior author Kazushige Touhara, professor and biochemist at the University of Tokyo, told IFLScience.
This romantically named stink flirting is possible thanks to well-developed scent glands that are found on the wrists of lemurs. These glands produce a host of smells that indicate reproductive status, territory as well as a lemur’s social rank.
By observing lemurs at the Japanese Monkey Centre (JMC) in Aichi and The Research Institute of Evolutionary Biology in Tokyo, Touhara and his team revealed that during the breeding season female lemurs were more interested in male scent markings and would sniff them more often and for longer compared to when they weren’t in heat. When the researchers isolated females and presented them with the male’s fruity in-season perfume, they would smell it for twice as long compared to their interest in the more bitter, off-season male fragrance.
Using detailed chemical analysis, the researchers identified three aldehyde compounds which made the scent – dodecanal, 12-methyltridecanal, and tetradecanal. They tested the power of these alluring compounds on their females and found that they were only effective as an enticing perfume when all three were presented together. Turns out, it’s not just lemurs benefiting from these pleasing compounds.
Younger males' scent was also more attractive to females as they produced the highest quantities of these compounds. but older females were immune to the sexy perfume as those beyond their reproductive prime weren't interested in the male’s scent, on or off-season.
While the research is an exciting discovery of what could prove to be the first primate pheromones, more investigation is needed to understand exactly how their production impacts sexual behavior and reproductive success. "Currently, we cannot yet refer to the odors identified in lemurs as official sex pheromones due to the classical scientific definition that a pheromone must be used for communication only between members of a single species. We do not know yet whether the identified odors work only within lemurs," said Touhara to IFLScience.
Lemurs have a more established sense of smell compared to humans and apes, but it's still possible we are capable of picking up on scent cues such as when parents are affected by the smell of their baby's head. Touhara suggests this is "the next big question" for the team's future research in trying to identify odors utilized in human chemical communication.