Katharina von Dürckheim calls it “pachyderm perfume” — the olfactory messages that African elephants emit in their urine, dung and secretions from the temporal glands when they meet each other.
African elephants have a “fascinating” ritualised greeting ceremony when they get together, says Von Dürckheim, who studied their sense of smell as part of her recent PhD in conservation ecology at Stellenbosch University.
“No matter how often we’d work with the tame elephants, they’d still always do it too. They’d urinate, defecate, secrete from their temporal glands near their eyes, rumble, trumpet, spin their bodies around and fan their ears to waft something that I call ‘pachyderm perfume’ around.”
Von Dürckheim, who leads the university’s Wildlife Free to Roam research programme, has shown how African elephants share a “herd odour” that helps them recognise members of their herd based on smell.
This has more to do with the bacteria they share in their ritualised greeting ceremonies than the fact that they might be related. The urine and dung elephants leave behind on these pathways are like “communication hubs”, she says.
“They contain olfactory messages that allow them to monitor which other elephants are around and are possibly ready to mate. When there’s a spot of urine on the ground, an elephant first blows onto the sandy spot to create a sort of dust storm of particles. It 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.”
Her work has shown how elephant body odour contains information about age, gender and individual identity.
As a child, Von Dürckheim often had the privilege of observing the highly ritualised way that African elephants greet each other while on family visits to various national parks. This is what led to her PhD topic.
“It was always such a wonderful moment, witnessing the trumpeting and the rumbling and the sort of affiliative way that they would touch each other and rub their bodies together.
“Then, also they were secreting dung and urine, and also from the temporal gland on the side of their faces, and as someone who is fascinated by perfume and body odour, I thought, what’s in that chemistry? Is there any information that pertains to their age, their sex, their dominance status or is there information saying, ‘Hi, I’m a relative of yours’ or ‘I belong to your bigger herd.’”
Hers was the first study to investigate the chemistry behind secretions from the genitals and buccal and temporal glands of free-ranging African elephant females.
The latter causes the typical “teary eyes” of an African elephant female, something rarely observed in Asian elephant females.
“Asian elephants don’t secrete as much as African elephants do. The females will secrete while giving birth or if they are distressed. African elephants, the girls, when they meet each other they secrete frequently and it’s usually the older girls who do it,” she said.
From both urine and dung, African elephants can discriminate between unfamiliar and familiar members of their species. They can identify between individual elephants based on what they detect from the “smell” released from temporal gland, buccal and genital secretions.
Genetics don’t seem to factor in. This was shown through Von Dürckheim’s work on the “odour-gene covariance”, or OGC. Hers was the first to study this in elephants.
“To study OGC, you examine blood and DNA, and you analyse the body chemistry of related and unrelated animals. You see whether because of genetic closeness, related animals have a more similar chemical profile to each other than to unrelated animals.”
She discovered that although related elephants did share many chemical compounds, these varied in intensity and identity. Her research showed the existence of individual identity odour profiles in African elephants, as well as a signature for age encoded in temporal gland and buccal secretions.
Olfactory signatures for genetic relatedness were found only in the labial secretions of adult sisters. Von Dürckheim was specifically interested in whether there is a tell-tale herd or group odour, given the social life of elephants, and their ability to recognise relatives.
She could not find a link, But an odour for “herd membership” seems to exist.
As with other social mammals such as hyenas and meerkats, this elephant group odour appears to be the result of bacteria that are shared through the frequent physical and affiliative behaviour of elephants.
“This is possibly what actually creates a particular herd scent — not whether the animals are related or not. However, this does not mean that elephants cannot recognise relatives, or that a genetic signature for relatedness does not exist. Much research hints at urine containing a genetic marker. This is yet to be researched in elephants.”
Working with elephants in captivity, Von Dürckheim found that they are highly proficient at scent discriminating between humans — and scent tracking a human across terrains.
“We put a person in the field, and an hour later we let the elephants track the person. They were successful 100% of the time. The results were quite revealing. Based on scent discrimination, elephants can differentiate between three generations of the same human family, and between at least nine different people. They learn superbly quickly.”