For orphaned elephants, friends may be key to stress relief

When a group of researchers set out to study the well-being of wild juvenile African savanna elephants in central Kenya, they had a theory: Orphaned elephants would be more stressed out than non-orphans. 

There’s a lot of evidence that the mother-child bond helps buffer against stress in animals, which has been demonstrated previously in rats, finches, and guinea pigs, says study leader Jenna Parker, a postdoctoral research fellow with the San Diego Zoo Wildlife Alliance and Colorado State University. Elephants have sophisticated social structures and deep familial bonds. Because orphaned elephants in the same region die at a higher rate than elephants with living mothers, it seemed like a no-brainer that surviving orphans would be stressed out.

The team, however, made an unexpected finding: There really wasn’t a difference in the stress hormone levels of orphaned and non-orphaned elephants, as long as they lived with family members, such as aunts, cousins, or siblings. Elephants—even the orphans—that lived in groups with peers their own age turned out to be under less stress than those that didn’t. In short, elephants may get by with a little help from their friends. 

“We expected to see higher levels [of stress hormones] in orphaned elephants,” says Parker, “because until age eight or nine, elephants are rarely more than 10 meters from their mother.” 

With human-wildlife conflict and drought looming threats to elephants in the region, the findings published today in Communications Biology offer new insight into how having a strong peer group may contribute to elephants’ survival. In 2021, the International Union for Conservation of Nature listed the African savanna elephant as endangered. About 36,000 remain in Kenya, according to a 2021 national census.

This information could also help rehabilitation facilities that take in orphaned elephants set the animals up for a successful future in the wild—releasing them in large groups of bonded peers, for example.

Measuring stress through elephant dung

Parker began the study in 2015, when the Samburu National Reserve region had endured several years of increased elephant poaching. 

At the time, she says, her colleagues at Colorado State University realized that “we weren’t really understanding the full impact of poaching. When an elephant is killed, there are all these consequences for the elephants she or he is bonded to.” They wanted to look at indirect impacts: How does the poaching of a mother affect the social and physiological well-being of an orphan?

The team first looked at survival rates, and found that orphaned elephants in Samburu had lower survival rates than non-orphaned elephants. Next, they wanted to look at the survivors: Were the orphans under stress? 

To find out, they tested the elephants’ dung for concentrations of glucocorticoid metabolites—a substance produced as a response to stress in the body. “It’s a good way to look at stress hormones because it’s not invasive,” says Parker. “You just wait for them to poop and collect it.” 

Generally, higher levels would be associated with higher stress, but a one-off sample that shows high levels is inconclusive, Parker explains, because the elephants “could have just come across a lion earlier in the day.” Between 2015 and 2016, the team collected and tested 496 dung samples from 37 juvenile female elephants: 25 of which had been orphaned, and 12 that had not. The orphaned elephants were an average age of five years old when they lost their mothers. 

Although the team was taken aback that orphaned elephants didn’t show higher stress levels than elephants that still lived with their mothers, the fact that peer groups seemed to play such a key role wasn’t a shock. 

Parker recalls two orphans in the study, Frida and Rothko. “Frida had a floppy left ear and Rothko had a floppy right ear,” and they were inseparable, she says. “It was as though they had at least one good set of ears as long as they were together!”

The findings also fit with previous social research in African elephants, Parker says. “Orphans increase interaction with their age mates after their mother’s death.” She notes that dominance is structured by age in elephants: Older elephants may outrank younger elephants when it comes to food, for example, but peers are generally equals.

Setting orphaned elephants up for success

Parker works with orphaned elephants at Reteti Elephant Sanctuary, an orphanage in northern Kenya that rehabilitates and releases young elephants. (Learn how trailblazing communities in northern Kenya have come together to save orphaned elephants). 

Those elephants were in the back of her mind throughout this study, she says, because the findings show that releasing rehabilitated orphans in large groups with other same-aged elephants could set them up for initial success in the wild. 

Parker would like to see a similar study with a more specific population of elephants, such as those that have faced heavier poaching. 

Kathleen Gobush, a wildlife biologist with the IUCN’s African Elephant Specialist Group who was not involved in the study, says it would be interesting to follow this same group of elephants as they face an acute stressor, such as a wave of intense drought or a new wave of poaching.

“The bottom line here is that elephants need elephants,” says Gobush. “And when the worst happens, like losing a mother, some find new ways to survive and thrive.”