African elephants use ‘pachyderm scent’ to message each other
Katharina von Dürckheim calls it “pachyderm scent” – the olfactory messages that African elephants give off in their urine, feces and temporal gland secretions when they meet.
African elephants have a “fascinating” ritualized greeting ceremony when they come together, says Von Dürckheim, who studied their sense of smell as part of his recent doctorate in conservation ecology at the University of Stellenbosch.
“No matter how often we worked with the tame elephants, they always did too. They urinate, defecate, secrete from their temporal glands near their eyes, growl, trumpet, twist their bodies, and fan their ears to give off something I call “pachyderm scent.”
Von Dürckheim, who heads the university Wildlife free to roam research program, showed how African elephants share a “herd scent” that helps them recognize members of their herd based on their scent.
It has more to do with the bacteria they share in their ritualized greeting ceremonies than whether they might be related. The urine and feces that elephants leave behind on these pathways are like “communication centers,” she says.
“They contain olfactory messages that allow them to monitor what other elephants are around and are possibly ready to mate. When there is a spot of urine on the ground, an elephant first blows on the sandy spot to creating a sort of dust storm of particles.He will inhale deeply through the trunk, sometimes transferring particles to the Jacobsons’ organ through the roof of the mouth, in what we call a flehmen response.
His work has shown how the body odor of elephants contains information about age, sex and individual identity.
As a child, Von Dürckheim often had the privilege of observing the highly ritualized manner in which African elephants greet each other during family visits to various national parks. This is what led to his doctoral topic.
“It was always such a wonderful time, to witness the trumpeting and the rumble and kind of affiliatively as they touched and rubbed their bodies.
“Then they were also secreting dung and urine, and also from the temporal gland on the side of their face, and as someone who is fascinated by perfumes and body odors, I thought, that there is there in that chemistry is there information regarding their age, gender, dominance status or is there information saying, “Hi, I’m a relative of yours” or “I belong to your largest flock”.
Hers was the first study to investigate the chemistry behind secretions from the genitals and oral and temporal glands of free-ranging female African elephants.
The latter causes the typical “watery eyes” of a female African elephant, which is rarely seen in female Asian elephants.
“Asian elephants don’t secrete as much as African elephants. Females secrete when giving birth or if in distress. African elephants, girls, when they meet they secrete frequently and it’s usually the older girls that do it,” she said.
From urine and feces, African elephants can distinguish between unfamiliar and familiar members of their species. They can identify individual elephants based on what they detect from the “smell” given off by secretions from the temporal, oral, and genital glands.
Genetics doesn’t seem to come into play. This was demonstrated by Von Dürckheim’s work on “gene-odor covariance“, or OGC. She was the first to study this in elephants.
“To study OGC, you look at blood and DNA, and you analyze the body chemistry of related and unrelated animals. You see if, due to genetic closeness, related animals have a more similar chemical profile to each other than to unrelated animals.
She found that although related elephants shared many chemical compounds, these varied in intensity and identity. His research has shown the existence of olfactory profiles of individual identity in African elephants, as well as a signature for age encoded in the temporal gland and oral secretions.
Olfactory signatures of genetic kinship have only been found in the labial secretions of adult sisters. Von Dürckheim was particularly interested in whether there is a telltale herd or group smell, given the social life of elephants and their ability to recognize relatives.
She couldn’t find a connection, but a “herd” smell seems to exist.
As with other social mammals such as hyenas and meerkats, this elephant group odor appears to be the result of bacteria that are shared by frequent elephant physical and affiliative behavior.
“This may be what really creates a particular herd odor – not whether the animals are related or not. However, this does not mean that elephants cannot recognize their parents or that there are no genetic signature for relatedness There is a lot of research suggesting that urine contains a genetic marker, this has not yet been studied in elephants.
Working with elephants in captivity, Von Dürckheim discovered that they are very proficient at distinguishing humans from scents and following a human’s scents through terrain.
“We put a person in the field and an hour later we let the elephants follow the person. They succeeded 100% of the time. The results were quite revealing. Based on olfactory discrimination, elephants can differentiate between three generations of the same human family and between at least nine different people. They learn super fast.