The last few years haven’t been easy for wild elephants in the Samburu and Buffalo Springs National Reserves of Kenya. Poaching and severe drought killed many adult females, leaving behind fragmented families and female orphan calves. These orphans survive less than nonorphans and have difficulties when trying to join other families.
Now, a new study by Colorado State University researchers has found that the orphaned elephants seem to benefit – physically and measurable – from the support of other young elephants. The researchers analyzed stress hormones in the elephants to better understand the physical impact of the loss of their mother over a long period and found that friends really do make a difference.
The findings showed that the elephants that had more friends from a similarly aged group had lower stress hormone levels. This suggests that this social network of support could reduce the stress triggered by the loss of a mother in these social and intelligent animals. As the research paper reads, social relationships have physiological impacts.
“If you’re out in the field, watching elephants, you can just tell that family life is everything,” Jenna Parker, study author, told BBC News. “Calves are rarely more than maybe ten meters from their mother until they’re about eight or nine years old. And if some of the elephants in a group go off, you’ll hear them calling to one another.”
Stress and elephants
When we are confronted with a stressor, the adrenal glands release more glucocorticoid (GC) hormones into the bloodstream. Previous studies have shown that the presence of one or more companions in wild primates and laboratory rodents can reduce the GC release and stress levels – a phenomenon known as social buffering. For some time, researchers have been wondering if the same thing is happening to elephants.
For their study, Parker and colleagues monitored groups of African elephants in Kenya for more than a year. They watched and waited for each individual to poop, as they had to obtain a dung sample to analyze. It’s not glamorous, but it’s important. “You have to have your binoculars and really keep an eye on their back ends and their tails,” Parker said.
The 25 elephants ranged in age from seven to 21 years and had lost their mothers between one and 19 years earlier due to poaching or drought. They also studied 12 non-orphaned elephants of similar ages. A key finding was that there was very little difference between orphans and non-orphans elephants in terms of long-term stress.
The study found that resilience was linked to other elephants’ social support. Animals with more similarly aged partners in their group had much lower stress hormone levels than others, regardless of whether they were orphaned. Short-term stress wasn’t analyzed as the study was done two years after the mother had died.
The findings could improve the management of orphaned elephants brought into captivity by providing them with similar-age companions to reduce their stress levels. Also, releasing groups of orphans from captivity who had previously bonded together could help them ease their transition back into the wild, the researchers argued.