For most of us, stress is something that comes and goes, usually in small doses. But others aren't so lucky. War, everyday violence, and starvation are a fact of life for millions around the world, with damage that extends far beyond immediate events. Trauma is etched deeply into the human brain, leaving an indelible legacy. Traumatology, the study of severe stress, is a core aspect of medical and scientific research. And we who work in neuroscience now know that trauma and its far-reaching effects are not limited to humans.
In 1996, game park rangers in South Africa began to find something very disturbing: alarming numbers of rhinoceroses that had been gored to death. In the period of a few years, more than one hundred were found. As unsettling and odd as these deaths were, even more bizarre was that the prime suspects were young bull elephants.
Though elephants are the planet's largest land mammals, they are herbivores that rarely engage in aggressive behavior, let alone cause fatal injuries. Furthermore, the South African rhino killings weren't isolated events. Other strange behaviors, including evidence of "false mounting" of rhinos (what would be termed rape in the case of humans) and mortal elephant-on-elephant violence, have been observed in India, Indonesia, Sri Lanka, Uganda, and Zambia.
In some parks, the biggest risk for a bull elephant is to be killed by another male. Even females, typically peaceful unless protecting their young, have begun unprovoked attacks on tourists.
It wasn't long before biologists began fitting the pieces of the puzzle together and realized that elephants are showing the effects of traumatic violence and social breakdown. The common characteristic of the killers is that they were orphaned at a young age and witnessed the systematic slaughter of family members. Such culls (planned killing to control populations), along with extensive habitat destruction and poaching, have reduced elephant populations to near extinction in some cases, and left formerly tight-knit, highly complex social groups in fragmented shambles.
The effects of stress cannot be overestimated, in animals or humans. Traumatic disruption from a single event can alter neural organization and lead to lifelong disorders in learning and coping abilities. Chronic or traumatic stress can even impair genes involved in neuron and synapse generation, thereby creating a vulnerability to psychological and emotional instability, compromised immunology, and other physical problems.
Elephant brains share with human brains similar mechanisms that govern thinking, feeling, perception, and behavior. Parts of the brain -- cortical and limbic structures -- responsible for processing and controlling emotions, traits, and social interactions, such as maternal behavior, facial recognition, play, sexual behavior, fear, aggression, and stress regulation, are common among all vertebrates (and even some invertebrates).
As Charles Darwin pointed out a century and a half ago, evolution guides body and mind. So when we learn that Happy, an Asian elephant at the Bronx Zoo, recognizes herself in a mirror, or that African elephant matriarchs bring their young to visit gravesites of past relatives, the idea of posttraumatic stress disorder in these animals should come as no surprise.
Since European colonization of lands where elephants roamed free for countless millennia, the pachyderm has been under siege (and the end of colonization has provided no relief). Human destruction has created a highly unstable, threatening world. Elephant psychosocial symptoms eerily mirror what we see in similarly stressed and disrupted human communities. The delinquent teenage bulls evoke a disturbingly familiar image of many young men, who, like the elephants, lack the steady mentoring of elders and react violently to traumas they have endured.
In addition to violence, neglectful mothering, and internecine fighting, there are even signs that elephants are becoming addicted to alcohol. Starving elephants have broken into village wine vats, ignoring more nutritious grains and other foods.
With their dramatically unusual actions, elephants are telling us something, and neuroscience is letting us hear their story loud and clear. Some say elephants are sending a message to stop destruction of the planet before it is too late -- an anthropomorphic claim about a nonhuman species, perhaps, but recent scientific discoveries have made differences between us and other animals seem awfully insignificant.
Can elephants survive? Statistics point to a dim future. As human population expands, elephants are being pushed into smaller and smaller areas that simply aren't big enough for them to successfully survive. Even if elephant culling is halted (and there is continued pressure to go on culling, despite scientific evidence of the harm it's doing), stress and disruptions may already be irreversible.
Without radical change, elephants will be lost forever. To save these and other endangered fellow inhabitants of the planet, humanity must listen to what they're telling us and put the needs of other species ahead of its own. We must realize that our needs and the needs of an awesome species like the elephant are the same.