A lemur rubbing on a sweetgum’s trunk leaving a unique trace of scent. Credit: Ipek Kulahc

Humans are great social beings because we have an extraordinary ability to distinguish between our fellow bretheren. If you don’t suffer from prosopagnosia, also known as “face blidness”, chances are you’ll be able to easily recognize a friend’s face or voice out of a myrriad of other humans. This kind of mental ability is extraordinary and most often taken for granted, so kudos to us humans!

We’re not alone, however. Studies have shown that some animals can do this too. For instance, dogs, horses, crows and monkeys can pair up the sounds of a friend’s voice with her face. Now, researchers at Duke Universities have found that ring-tailed lemurs can pair up the signals transmitted by their friends in an even more extraordinary fashion. Apparently, male lemurs can recognize the distinct scents and voices of a female even when she is nowhere in site with extraordinary accuracy.

I can smell your voice

These cat-sized primates are native to the African island of Madagascar and besides being extremely cute, lemurs posses an extremely keen sense of smell. Their genital secretions alone contain hundreds of odor molecules, and when a lemur marks his favorite tree, others can instantly recognize who the scent belongs to.

For their experiments, the Duke reserachers introduced 15 ring-tailed lemuers, one by one, in an outdoor enclusure where they were subjected to pairwise combinations of calls and scents from familiar females. Once the lemur went inside, a familar female’s call was played from a hidden loudspeaker positioned between two wooden rods –  one swabbed with a female’s scent and the other ‘unscented’ — so that the sounds and the scents came from the same location.

In general, the lemurs paid more attention to the sounds and smells in the matched trials in which the call they heard and the scent they smelled came from the same female, than in the mismatched trials when they heard one female and smelled another.

Both males and females spent more time sniffing and/or marking the scented rods in the matched trials than in the mismatched trials. Males also spent more time looking in the direction of a female’€™s call when her scent was present instead of another female’s scent.

Unlike shrieks, yips and wails, a lemur’s odors can linger long after the animal that made them has left the area. This ability to match odors and sounds may help a lemur figure out if the animal producing the scent is still nearby. For male, this may be of crucial importance in finding a mate. “If they detect a whiff of a familiar female and she’s still within earshot she can’t be far,” said Princeton graduate student and coauthor Ipek Kulahci.

Did you find this interesting? Well, lemurs have another ace up their sleves.These tiny primates live up to seven months each year in a physiological state known as torpor (a form of hibernation), where the regulation of body temperature stops and metabolism slows down. Amazingly, the lemurs can  drop their heart rate from 120 beats per minute to a mere 6, and breath extremely crawled. If a human drops or raises in body temperature just by two degrees, he’s toast. A lemur can withstand body temperature variations of up to 25 degrees! In fact, some reserachers claim that lemuers might hold the key for deep-space travel, by allowing humans to share their hibernating patterns.

The study appears online April 16 in Proceedings of the Royal Society B.