When faced with a charging elephant, people get a rush of hormones that can speed up their heart, make their hands shake, and cause a wide variety of bodily responses typical of a stress situation.By Melissa WrayIn Kruger National Park
But look at the picture from another angle - what do people do to elephants? Humans drive around game parks and spy on as many aspects of elephant life as they possibly can, they hunt elephants, chase them with helicopters to dart and collar them, and perform many other intrusions into the personal lives of these intelligent animals.
Elephant dung, vinegar, a freezer, a sieve, some test tubes, and a high-tech biomedical kit have helped form a clearer picture of what people do to stress elephants out. An observer can intensely study elephants, and spot all the elephant body language that warns of stress at various levels - tell-tales like flapping ears, elephants swinging their feet at a disturbance, head shakes, tails sticking straight out, mock and real charges and secretions from their temporal glands, amongst other behaviours.
However, just as a person may be internally stressed but appear outwardly calm, it is also possible for elephants to suffer unnoticed from stress until one day something causes aggressive behaviour that is seemingly out of proportion. A blood test can show what stress hormone levels are like in both people and elephants, but it is undoubtedly a lot easier to collect a blood sample from a human than from a wild elephant.
Researchers then turned their minds to other ways of finding out how much stress hormone is floating around in an animal's system, and discovered that urine and faeces contain chemicals called glucocorticoids, which are an indicator of stress. By collecting elephant dung after an elephant has moved on, a researcher can be relatively sure that they have not stressed the elephant out in the process of collecting a sample for stress testing.
WHAT TO DO WITH ELEPHANT DUNG
On average, it takes about a day and a half for a stressful event in an elephant's life to be expressed in their dung, so continued observation of elephants is necessary before dung collection is carried out to correlate the dung with the stressful event.
To perform stress hormone analysis on elephant dung, a golf ball sized piece of dung must be collected from the inner core of the various bits of dung in one excretion, mixed and mashed thoroughly, frozen, defrosted, pickled in vinegar for a while before draining the vinegar off, refrozen and shipped with a willing courier and the necessary permits to a lab (in this case in Missouri, America). Once at the lab, the dung is freeze-dried, ground, sieved and then subjected to laboratory tests with a hormone assay kit.
With a combination of elephant observation and dung collection, two masters students have found out more about what stresses elephants out when they interact with people. With the help of funding from the Amarula Elephant Research Programme, a study of elephant stress in Pilanesberg National Park and Mabula Game Reserve has been carried out. The Pilanesberg project, carried out by Tarryne Burke, had added financial assistance from PPC Cement.
TOURISTS AND HUMAN INFRASTRUCTURE CA-- STRESS
Yolanda Pretorius, working in Mabula, discovered a variety of interesting social behaviour amongst the elephants. The elephants were all orphans that had been brought together, and lacked the experience of growing up in a larger elephant society. In addition to her behavioural monitoring, hormone analysis of the dung samples she collected showed that the reserve's elephants were most stressed at their feeding areas, and in the section of the reserve where the majority of the houses and the main lodge were located.
Spikes in stress hormone levels in the dung also corresponded to daily changes in the intensity of game drives near the elephants, and uncontrolled game viewing with many vehicles clustering around the elephants produced the worst stress. In the Pilanesberg National Park, Tarryne Burke was able to monitor elephants in the context of tourist activity, hunting of elephant bulls, and the capture and collaring of female elephants. In general, the elephants' stress hormone levels were lower in the wet season than the dry season. Bull elephants showed daily fluctuations in their hormone levels, with highest levels in the evenings.
THE EFFECTS OF HUNTING AND DARTING ELEPHANTS
The Pilanesberg elephants were also stressed by tourists, with breeding herds showing increased stress levels in the areas of the park that were most popular with tourists. Surprisingly, the darting and immobilising of female elephants had little effect on stress hormone levels. Tarryne found that there were no significant changes from the elephants' normal hormone levels before or after the event.
The rest of the herd also seemed to be unaffected hormonally by the immobilisation activities. This is thought to be because the elephants are reunited after the darting, with the longest the elephants were separated in all the immobilisations being less than three-quarters of an hour.
In contrast to this, the four hunts of bull elephants that took place had stressful repercussions for six bull elephants that generally associated with the hunted animals. Although appearing calm within a day of the hunt, the associated bull elephants showed significantly elevated stress hormone levels for four days after the hunt. This stress seemed to be transmitted to the other elephants in the park, with the bulls that did not spend a lot of time with the hunted animals and the breeding herds showing increased stress levels for up to a month after the hunting event.
Tarryne intensely watched the elephants throughout the study, but could not detect behavioural changes in the elephants for more than a day after the hunting event. This shows the sensitivity of the dung analysis, and gives insight into planning future management interventions.
With a simple dung ball giving out so much information when treated in the correct manner, elephant researchers are now hoping that small kits will be produced that would allow a researcher in the field to do an instant test for stress hormone levels.
This would allow reserve managers to better manage human-elephant interactions, through things like closing roads in peak stress times to provide tourist-free refuges for elephants, stopping off-road driving in places like the Kruger Park, restricting the number of vehicles at an elephant sighting in smaller reserves or by better timing or spacing events that stress elephants out.
Tourists can also be informed on how to treat elephant sightings, with suggestions such as approaching elephants slowly and remaining 30 to 50 metres away to ensure that the elephants' behaviour remains unaffected by the presence of people or cars. If the right kind of future research is performed and management decisions made accordingly, the incidence of high tourist stress levels caused by charging elephants could drop dramatically...