How Elephants Got PTSD

I’m not sure if every social creature can be said to have a society, but elephants certainly do. Along with some primates, whales and dolphins, and people, elephants have some of the most complex and cerebral relationships in the animal world. Given that elephants are long-lived, mourn their dead, never leave their families, and are said to never forget, it shouldn’t come as a surprise that disrupting their society has repercussions that can be seen for decades.

Researchers from the University of Sussex found that elephants who were orphaned by an elephant cull in Kruger National Park are still socially maladjusted, even though the practice of controlling elephant populations through killing was stopped almost two decades ago.

The researchers say the elephants were exposed to trauma and dislocation and dissolution of their family unit, with behaviors “akin to the post-traumatic stress disorder experienced by humans following extremely traumatic events.” Their “key decision-making ability,” they write, had been significantly altered. The study, published in Frontiers of Zoology, compared a population of those elephants who were transplanted to Pilanesberg National Park in South Africa with undisturbed and unculled herds in Amboseli National Park in Kenya.

The Pilanesberg orphan elephants have had social problems since they were first introduced. “The effects of their broken home life,” remarked an LA Times article from 1998, included teenage bulls taking to mating with the white rhinoceros population, after older elephant cows rebuffed their advances. This led to the death of several rhinos; at another wildlife reserve, some 107 rhinos died from elephant attacks. Some elephant bulls charged vehicles and groups of tourists; in one incident a German businessman was killed when bulls attacked him as he tried to retrieve his toddler daughter, who had fallen out of the car window.

Elephants at Amboseli National Park in Kenya via Flickr

In response to the young elephants’ dangerous behavior, park zoologists introduced older bull elephants from Kruger, in hopes that they would instill manners in the younger bulls.

But comparisons between Pilanesberg and Amboseli elephants revealed that the transplanted elephants never fully developed their social skills. The researchers played the sounds of elephants, both familiar and unfamiliar to the herds, and compared their responses.

Elephant orphans at the David Sheldrick Wildlife Trust, Nairobi/Flickr

The unculled Amboseli elephants heard the unfamiliar call and bunched together defensively—textbook elephant behavior. “It’s what elephants should do when faced with a genuine stranger,” lead researcher Karen McComb told the BBC. They were also less stressed at the sounds of a known elephant.

The Pilanesberg herd, though, didn’t have a pattern of response—McComb said it was just “completely random.” They didn’t seem to able to distinguish between friend or foe; they didn’t seem to know when the call was a mature, dominating elephant or a younger, less threatening one. “Their social understanding has been impaired,” said McComb.

Top photo via Flickr