The first rule of chimpanzee trekking? Don’t run!

When my tracker, Robert, told me this before my first foray into the mountains of Mahale Mountains National Park in Tanzania, I was befuddled. I was expecting him to say, “Don’t approach the chimps.” Or perhaps he'd offer a stern warning about why you shouldn’t cough on the primates.

But I'd been so distracted by the visions of roly-poly chimp babies dancing in my head that I’d forgotten that they can do some serious damage if you make them mad.

I was 7 years old when I held my first copy of National Geographic magazine, which had a feature on Jane Goodall. From the moment that I took in her serene gaze, I was hooked on the idea of a life spent learning about animals. “A mirror of humanity,” she said about our closest living relative.

I immediately started planning a trip to Tanzania to see them for myself, a journey that took almost three decades to come to fruition.

In the meantime, I spent hours staring at their captive cousins in the zoo, wondering what they must think of all the humans peering at them. I even went so far as to attend veterinary school with the idea of pursuing a career in primate medicine.

But that goal evaporated the first time I encountered a chimpanzee in a windowless room at a lab facility. The medium-size male sat forlornly in a metal cage, looking at me with such devastating awareness that I’m sure if he possessed the capacity for speech, he'd have asked me, “Why?”

Instead, I pursued a more traditional career path as a small animal veterinarian, but my love for wildlife persists to this day. This is how I found myself on a plane bound for Africa, giddy with excitement at the thought of seeing chimpanzees as they were meant to be, swinging in trees and hooting.

Tanzania is rightfully very protective of its chimpanzee population. Of the 800 chimps who live in the Mahale Mountains National Park, only 40 or so members of the “M” community are acclimated to human contact. This group has been around people since 1965, when Kyoto University established a primate station in the park with the strict mandate that humans (including tourists) observe the animals in as nondisruptive a manner as possible. There’s no feeding and no contact — just watching and photographing.

Each morning at 7 a.m., trackers set off into the forest to locate the community in the dense mountain rain forest above Lake Tanganyika. Once they spot the group, the trackers radio back to camp. Eager tourists like myself then set off in pursuit of the chimps alongside park rangers and guides, our cameras and surgical masks in hand.

After an hour of intense hiking — and dodging bush pig scat — I heard a sound in the distance, a low hooting that built into a crescendo as it echoed off the leafy canopy. “Put on your masks,” Robert said. The requirement was put into effect after an influenza outbreak killed several chimpanzees in 1996.

Once we were suitably protected, he led us around a corner and under a vine — and there they were. Three large males sat on the trail, amiably picking ticks off of each other. They looked at us interlopers, gave the chimpanzee equivalent of a shrug and went right back to their tick picking.

High in the trees, the females plucked ripe figs to eat, popping two or three at a time into their mouths before handing some to the babies who clung to their chests. The little ones used their fingers and sometimes their toes to stuff the figs farther into their mouths, hooting happily.

We stood stock still for half an hour. The only sound you could hear was the click of a camera shutter. (There was also the occasional squeal of delight — mostly from me — when a chimp did something exceptionally cute.) Every few minutes, a chimp would swing down from a tree and walk past us on the path, black fur brushing against our legs.

It was a magical experience to observe the chimps eat, groom and play in such a natural manner. I marveled at their dexterous fingers, as they gestured toward one another — as well as their intelligent eyes, which took in the big, hairless intruders and decided that we were uninteresting.

“Alpha chimp coming! Stand back! Stand back!” Robert suddenly yelled. Down the path barreled Pimu, the aggressive brute in charge of the group.

For the past four years, Robert explained, Pimu had reigned through intimidation and force. As he approached, the females swung higher into the branches. The males scattered. Pimu slapped the ground, staring down each of us before turning his back on our group to have lunch.

I later learned that, the day after I left, the other males in the community attacked Pimu. In an exceptionally unusual display of violence, they killed him. I spoke to the camp manager, Steve, about the event, which upset both the rangers and the tourists who observed it.

“Well,” he said, sighing in resignation, “they are more like us than we’d care to admit.”

For more on Dr. Jessica Vogelsang's amazing experiences at chimp camp, watch this footage that she captured while in Tanzania.

Dr. Jessica Vogelsang is a graduate of the University of California, Davis School of Veterinary Medicine. When she's not trekking in Africa or spaying dogs on the shores of the Amazon, you can find her surfing with her Golden Retriever, Brody, and writing for pawcurious.com.