The Elephant Man
Great herds of elephants once ambled over much of the African continent. Today, thanks to centuries of hunting and habitat loss, far fewer of the prodigious pachyderms roam free. Most, in fact, are confined to game preserves.
These preserves are often ideal habitats, and are generally credited with bringing African elephants back from the brink of extinction, says Joshua Millspaugh, an MU assistant professor of fisheries and wildlife who is analyzing elephant population ecology with South African researchers from the University of KwaZulu-Natal. Still, he adds, life on the preserve is no walk in the park: "For the younger, newer arrivals in particular, we've found it to be a stressful experience."
It's easy to understand why. To remain economically viable, preserves must cater not just to the needs of animals, but also to the desires of visitors who pay to see them. Tourists, even those of the "eco" variety, demand elephant encounters. "In South Africa, as elsewhere, game managers want wildlife to be visible," Millspaugh says. "They want people to come in and see them."
Elephants feel differently. People make them uneasy, and uneasy elephants go to great lengths to avoid even the most conscientious wildlife watcher. They stay away from roads. They become nocturnal. They sometimes get aggressive. And humans aren't the only problem. Drought conditions, an improper balance of young to old elephants in the herd, even lightning storms can contribute to elephant anxiety.
Millspaugh is uniquely suited to help. The New York native grew up knowing he wanted nothing more than to pursue a career in natural resources: He became involved in elephant issues after a trip to an African game preserve five years ago. Though it was early in his academic career, the 30-year-old Millspaugh already had acquired a set of skills that would be crucial to helping South African scientists determine what stressors in the park were most likely to cause problems.
As a graduate student at the University of Washington, he had utilized an elegant, if potentially malodorous, way of determining stress response in large mammals, in this case elk. It involved determining levels of cortisol, a hormone associated with stress, in field samples of feces.
"When an animal becomes stressed, cortisol is released into its system," Millspaugh explains. "It shows up immediately in the blood; it takes about 20 minutes or so to show up in saliva."
And that's not the end of the story, he says. Even hours later, "those hormones are still circulating. After they reach the liver, where they are metabolized, they eventually wind up in the large intestine, where they are processed into fecal material about 24 hours later in large mammals."
That's why stool is perfect for stress research, Millspaugh says: "The only other way that we've been able to do stress measures in animals is by collecting blood. But think about that: The very process of collecting blood is going to be stressful for the animal, and that means we get a biased sample."
Elephants eat a lot, from 100 to 500 pounds of vegetation each day, and produce a great deal of dung. Team members from KwaZulu-Natal collect a small amount from each of the cohort of elephants being monitored and, after treating it with a vinegar solution to satisfy U.S. Customs Service regulations, dry it and carefully place it into small plastic vials. These are packed in dry ice and shipped to MU, where they are deposited in a nondescript top-loading freezer in Millspaugh's laboratory.
The lab is housed in a small, whitewashed basement room. Visitors expecting a whiff of the South African bush will be disappointed. Feces samples, which look like a powdery, fibrous dried herb, have no smell.
Millspaugh explains that his most recent samples come from elephants in seven South African parks, where elephants to be studied are selected on the basis of age and sex. Millspaugh's assistant and wife of six years, MU fisheries and wildlife research specialist Rami Woods, exposes the processed feces to a radioactive isotope. Tracers from this radioactive material are added to the samples, allowing a gamma counter to record fecal corticoid levels for each elephant.
Woods charts these levels over time, giving researchers a longitudinal view of points at which the elephants experienced heightened stress. By comparing this data to field notes, Millspaugh and his South African colleagues can identify the particular events or conditions that produced this stress, then develop strategies for mitigating their effects.
The good news, according to their findings, is that over time elephants adapt to stress reasonably well. "I think this relates to those individuals being conditioned and getting used to that activity over the course of many years," Millspaugh says. The not-so-good news is that young elephants are probably more stressed than anyone suspected. "I am surprised at how stressed they seem to be, their levels are really quite high. That's compared to work we've done with captive individuals and against other free-ranging elephants."
Millspaugh, on the other hand, seems perfectly at ease, despite an afternoon of running from a conference to a media interview to a session with a group of students who would soon be presenting research findings to National Park Service officials in South Dakota. "I love this work," he says. "I really am a lucky man."