Four hundred pounds of mostly rock-solid muscle, three-inch canine teeth, jaws that could crack coconuts—Dr. Chris Whittier’s work certainly does involve some unusual patients.

Whittier makes his living—and follows his passion—with the Mountain Gorilla Veterinary Project (MGVP), a nonprofit affiliated with the Maryland Zoo in Baltimore. He and his wife, fellow field veterinarian Felicia Nutter, are two of a small number charged with providing medical care to approximately 700 gorillas along the mountainous borders of Uganda, Rwanda, and the Democratic Republic of Congo. About 380 gorillas live within three national parks in the Virunga volcanic region of those African nations. Another 320 make their home in the Bwindi Impenetrable Forest in Uganda.

“If there were no poaching, no human contact, and especially if the forests hadn’t been cut down and the parks shrunken, there would be a lot more,” says Whittier, who earned a DVM degree from the Tufts University School of Veterinary Medicine and is finishing his PhD work at North Carolina State University. He joined the MGVP in 2001 to do doctoral research and has since worked with the program in various capacities, signing on as a full-time Rwandan-based field vet in 2004.

Though some of his days are filled with the comparatively mundane tasks of administrative work, one to three times a week Whittier leaves the office behind for the field. Depending upon the gorilla group being observed or treated and a number of other factors, the commute to the gorillas’ habitat includes a drive of anywhere between 20 minutes and several hours, followed sometimes by a two-minute flat walk through farm fields, other times by a five- to six-hour hike up steep, muddy, volcanic slopes.

The difficult conditions are worth it, according to Whittier, and the job comes with its fair share of rewards. “The obvious and biggest one is seeing—and getting to hang out with—healthy gorillas,” he says, “and especially seeing ones we’ve treated recover and go on to live happy, healthy lives. There are also more abstract things like the satisfaction of seeing the population rise and the rare acknowledgement that we have contributed to that in some way with our relatively specialized and direct expertise.”

Though the mountain gorillas have increased in number in recent decades, there are still numerous perils that endanger these highly social animals. Gorillas will sometimes become snared in traps intended for other animals and also have fallen prey to a large number of medical conditions that affect humans, including respiratory diseases such as the flu and pneumonia.

“We often fear—but have an almost impossible time proving—these are caused by human contact,” says Whittier, whose PhD research examines diseases to which mountain gorillas have proven susceptible.

The opportunity for exposure is great. Despite the sometimes lengthy treks to reach them, the gorillas do not live in remote regions. According to Whittier, the human population density of the districts surrounding the parks matches those of the city and suburban areas of Boston, Oakland, and Chicago. There is also a lot of human activity in the parks. On an average day, 200 to 300 people (tourists, guides, trackers, rangers, anti-poaching teams, military escorts, and vets) visit the Rwandan side of the park, as do an unknown number of other military patrols that protect the area and the gorillas.

“More than 70 percent of the Virunga gorillas are habituated to human presence,” Whittier says, “which basically means they are visited—and protected—by humans for up to eight hours a day, 365 days a year.” Those humans sometimes get within a meter of the animals and occasionally make physical contact, despite rules to prevent such behavior. Of course, the gorillas don’t always follow the rules either.

Close contact is required when Whittier is in the field, though direct contact is rare. His work is approximately 98 percent observation and monitoring and 2 percent actual treatment. “We use handheld computers to log observational clinical data—a cut here, a runny nose, normal appetite—and I take lots of photos to document things,” explains Whittier.

When it comes time for treatment, one-on-one contact is not always necessary. Sometimes medicine can be administered via dart gun. When physical contact is required, Whittier and company take precautions to protect themselves. The gorilla being treated is immobilized, but the patient’s family members are not, which can result in tense situations.

“We almost always have to chase the others away,” explains Whittier. “We do this caveman-style—with brave men and big sticks—and so far, it’s worked.

“Gorillas don’t seem to realize how easily they can harm or kill us because it’s not really in their nature,” says Whittier. “Although they’re not as shy and gentle as often portrayed, they are not as dangerous and aggressive as once thought, either.”