Quest: Mountain Gorillas: Discovery Channel

Hopeful Signs for 2009

  One of our project's main goals is to promote a healthier environment for people as well as gorillas. This is the one-health medicine concept. We can prevent medical problems in the gorillas by preventing problems in other species, including domestic animals, other wildlife and humans — even entire ecosystems.

Security Concerns

The other night I was one of several guests at a small dinner party in Rwanda. It had rained all day — and most of the previous night — but the skies had cleared about an hour before dark. It was the first time in weeks I'd driven up the road to park headquarters, having been on a break in the U.S. to promote Ted's and my new book. I drove slowly, swerving to avoid bicycles, pedestrians, goats, mini-buses and the occasional pollution-belching truck.

Another Coughing Gorilla Group

Elisabeth called me with worrisome news: "The chief has a small cough, and four others." She'd just returned from Kwitonda Group, a family of 19 mountain gorillas. My brain didn't want to accept the information. If Kwitonda and his group had come down with respiratory disease, it would bring the total to four groups in four months (in Rwanda). Yikes.

Another Sick Infant

I've been back in Rwanda for several weeks. As always, I spent two of them in self-imposed quarantine. Any time one of the vets travels on an airplane, we risk exposure to infectious diseases carried by fellow travelers. Though I wash my hands often and stay away from people who appear sick, it's impossible to eliminate the risk.

Is Ururabo's Baby Sick?

On Day 15 of the Susa Group respiratory outbreak, a cool, rainy morning, I stood in one place for two hours watching three sick gorillas. The longer I stayed, the more I worried about what we'd find the next day. Ururabo, a first-time mother with a 3-month-old baby, coughed and picked her nose. Her baby coughed and sneezed; white fluid ran down from each nostril. He breathed through his mouth's pursed lips.

Chimpanzee Park

Angolan colobus monkey, Nyungwe, Rwanda

Magda and I recently returned from a whirlwind three-day road trip to Nyungwe forest, Rwanda's newest national park, where we participated in a workshop designed to establish protocols for chimpanzee ecotourism. Magda is a chimp expert, having worked previously at two national parks in Tanzania, Gombe and Mahale. She brought all of her experience and knowledge to share at this meeting. My role was to share the health protocols we currently have in place for the mountain gorillas as a starting point for Nyungwe.

Forest caterpillar, Nyungwe National Park

During our long drive, I asked Magda dozens of questions. I wanted to know more about how things work at the research and tourist camps in Tanzania, where tracking habituated chimps has been going on for many years. In Nyungwe, the process is beginning with two small chimp communities and one large one.

Whereas gorillas live together in stable groups, chimps live in communities of grouped individuals whose composition changes frequently. Like mountain gorillas, chimps are susceptible to human diseases, so the risk of transmission will increase as they become habituated to people.

ORTPN staff Dr. Julius Nziza (veterinarian) in Nyungwe National Park

Bill Weber of the Wildlife Conservation Society organized the workshop. He and his wife, Amy Vedder, helped establish ecotourism for mountain gorillas in the late 1980s. Bill understands that establishing protocols for human visitors can go a long way toward preventing problems, so he organized a series of meetings to address all aspects of park management, including health.

Magda and I were happy to find that Dr. Julius Nziza had just arrived at Nyungwe as the on-site vet. We've invited him to several sessions of our MGVP training rounds, and he's keen to learn more. His participation will be key.

Male chimpanzee, Nyungwe National Park

During the workshop, Magda and I discussed the findings of a newly published scientific paper. Chimp researchers in the Tai forest (Ivory Coast, Africa) observed multiple outbreaks of respiratory illness in their subject animals. The morbidity rate, or the percent of the animals affected in each chimp community, was high (averaging 92.2 percent). In several outbreaks as many as eight individuals from one community died (18 percent).

Respiratory outbreaks also occurred among people living in the research camp. Though her own findings have not been published, Magda has treated chimps suffering from bacterial pneumonia thought to be secondary to a viral respiratory infection introduced by humans.

Male chimpanzee, Nyungwe National Park

The Tai forest paper examined the source of the respiratory viruses. Though samples were available for only a handful of outbreaks, the results clearly showed that the chimps were infected with one of two types of human-origin Paramyxovirus. The virus strains matched epidemics circulating in people elsewhere in the world, including Asia and North America.

This data proves what scientists have long suspected, a suspicion strong enough to serve as the basis for our current gorilla ecotourism guidelines: that humans have introduced novel pathogens into populations of free-living great apes.

Three male chimpanzees, Nyungwe National Park

Tourists and researchers are not the only risk to the chimps (or gorillas). Disease outbreaks that occur in villages bordering parks like Nyungwe also pose a huge threat. Anyone who lives in the community can pick up an infection and bring it to the park, including staff members.

An outbreak of meningitis, for example, could spread quickly. Humans can be vaccinated against these and other diseases, but vaccination is logistically a very difficult procedure with free-living apes — and chimps can move faster and farther than gorillas. Clearly, prevention of disease transmission is the key.

With respect to health protocols for ecotourism, we cannot know for certain if a visitor has just been exposed to a nasty virus. Obviously, keeping a safe distance from the chimps or gorillas reduces the risk of disease transmission, and it's also important in terms of minimizing stress to the animals. But under favorable conditions of temperature, moisture and wind, aerosolized droplets containing diseases can survive longer and float farther than most of us can imagine. Face masks can greatly reduce the spread of disease, but only if used properly.

Drs. Julius Nziza (ORTPN) and Magdalena Braum (MGVP) examine the
carcass of a dead monkey in Nyungwe National Park.

Throughout our formal and informal discussions at Nyungwe, I stressed the importance of practicing good basic hygiene — on the part of both staff and tourists. Frequent hand-washing with soap and water and wearing only clean clothes in and out of the forest are relatively easy precautions to note and remember.

Guide and tracker health is equally important. We recommended that Nyungwe adopt an employee health program similar to the one MGVP supports in the Virungas.

Tea plantation near Nyungwe National Park

In addition, Julius plans to become acquainted with the local health officials so that if there is an outbreak of illness in the community, he'll know about it. In such a case, the wisest move may be to stop chimp visits until the illness has been identified and contained.

Finally, all of these preventive measures must be communicated to tourists, researchers and park staff effectively and regularly. If people don't understand the risks, they're less likely to follow the hygiene and distance protocols that are in place.

Male chimpanzee feasting on ripe figs, Nyungwe National Park

As Magda and I learned for ourselves during the two days we tracked chimps at Nyungwe, distance is less of a problem while the chimps are not yet habituated to humans.

On our first day, we found three males feasting on figs. They hooted several times. Magda explained they were calling the females, who weren’t likely to show up with all of us around. I’d never seen any animal fill his mouth as full as one chimp did with figs. Had I not seen him put the fruit in his mouth, I would have thought something was wrong with his face!

Fresh chimpanzee track, Nyungwe National Forest

On the second day, we spent the morning crisscrossing a patch of forest with the trackers, looking for the same chimp community we'd visited the day before. Though we could hear the chimps — their voices echoed from at least two locations — and found fresh tracks, we made little progress for several hours.

Finally, we tracked a group of chimps making their way to the familiar fig tree. Three males climbed up to feed, though not the same trio as the day before. Once again, they called to the females; once again, none appeared. Magda and I left Nyungwe worrying less about disease for the time being. But when the chimps do become fully habituated, the risks will increase exponentially.

[Rwanda, March 12, 2008. Pictures: Dr. Lucy Spelman/MGVP]

A Visit to Uganda

A new camp for refugees from the D.R.C. in Kisoro, Uganda, Nov. 10, 2007.

I continued my travels in Uganda last week, first on safari with friends, then back to work with gorillas (more about them in a moment).

Early on, in Kisoro, we drove past a refugee camp set up by M.O.N.U.C., the U.N. mission in the Democratic Republic of Congo. The camp is just off the main road connecting the Virunga Mountains with Bwindi Impenetrable Forest, the only two places in the world where mountain gorillas live. Though the refugees have access to basic health care and vaccinations, any number of diseases could whip through this camp, putting people, as well as the nearby mountain gorillas, at risk.

Our next encounter with M.O.N.U.C. was a good deal less positive. We were in Queen Elizabeth Park on a game drive. Our amazing guide, Francis Kiwanuka, had spotted several lions after hours of searching. The male lion had a swollen muzzle, so of course I was trying to get a better look at him.

Suddenly, two U.N. trucks drove up and parked behind us, engines running. Dozens of people got out and continued talking. The lions moved away and so did we.

A male African lion in Queen Elizabeth Park, Uganda, Nov. 13, 2007.

Only about 100 lions remain in the entire park, a decline in population caused by the poisoning of lions by cattle farmers who prefer to protect their herds in this way rather than wait for compensation for their losses from the Uganda Wildlife Authority (U.W.A.).

Evidently, M.O.N.U.C. staff visit the park weekly during their breaks. Our safari group was disappointed and disheartened by their behavior. I don't think it can be good for these few lions to have people visiting the park who don't observe common safari etiquette, which calls for visitors to turn off their vehicles, stay inside and remain quiet around the animals.

A female leopard in Queen Elizabeth Park, Uganda, Nov. 13, 2007.

Francis quickly put some distance between our truck and the U.N. group. We continued on our game drive, passing a huge herd of elephants, one of many we glimpsed during our three-day safari.

Suddenly, Francis stopped, turned off the engine and pointed upward. A leopard! She too had a minor medical problem — a cloudy right eye with a bit of discharge. She noticed us but then went back to sleep . . . until the U.N. trucks showed up. She was long gone before they all got out and walked around her tree.

Francis Kiwanuka, nature guide and expert driver.

Francis himself was as impressive as the animals we saw on our Ugandan safari. He works for Volcanoes Safaris, a company that manages several eco-lodges in Central Africa. We'd hired him through Terra Incognita Ecotours, a company that donates to M.G.V.P. when guests visit our project in Rwanda.

These tour companies, as personified by Francis, offer proof that people and wildlife can live in balance with mutual respect for one another's boundaries. As for the U.N., maybe the Queen of England can ask them to mind their manners — this week she is due to visit the park named in her honor.

M.G.V.P.'s new field office in Buhoma, Uganda, adjacent to Bwindi Impenetrable Forest.

On my own I traveled next to Buhoma, Uganda, near the boundary of the Bwindi Impenetrable Forest. Bwindi is not far from the Virungas, but the drive on winding often muddy mountain roads with a stop at the border crossing from Rwanda takes about eight hours.

M.G.V.P.'s Ugandan field vet, Dr. Benard Ssebide, is based in the Buhoma area and we planned to do a few routine health checks together. Benard also wanted to give me an update on the new M.G.V.P. field vet office, still under construction.

A mother and her infant in the Nkuringo Group, Bwindi Impenetrable Forest, Uganda.

Bwindi is home to half the world's 720 mountain gorillas, though only about a quarter of these have been habituated to people. The percentage is much higher (75 percent) for the gorillas that live in the Virunga Massif of Rwanda, D.R.C. and Uganda.

Most scientists say that the two populations separated about 500 years ago — the result of logging and agriculture. Compared with the Virunga gorillas, Bwindi gorillas live at lower elevations in tree-covered peaks and valleys, eat a greater variety of plants, and have shorter hair.

Dr. Benard Ssebide stands inside M.G.V.P.'s newly constructed Buhoma field office.

To make a cell phone call, Benard must drive to a particular spot on the road where he can get decent reception. His office is wherever he finds a spot to land.

Recently, though, M.G.V.P. has co-funded the construction of a small building. One side houses M.G.V.P.'s new Uganda field office and it's almost ready. The other side was funded by a small business owner who planned to open an Internet cafe. Now we're hearing that this may never happen. So for now, sending email or talking by SKYPE in this area remains a dream.

Buzinza's infant in Bwindi’s Rushegura Group acts fine,
despite multiple small white lesions on the face.

I trekked with Benard and U.W.A. rangers to see Bwindi's Rushegura Group of mountain gorillas. Benard has been monitoring a 10-month-old in the group. It shows no signs of ill health except for multiple whitish-gray, plaque-like lesions on its chin, nostrils and lips. These lesions appear viral — possibly herpes or pox or papilloma (warts) — and have been observed on other infant gorillas. Indeed, during this visit, we noticed another infant, an 8-month-old, with similar facial lesions.

Kyirinvi's infant in Bwindi's Rushegura Group also has some small white lesions on the face.

Since the skin condition doesn't make the infants sick, we have not intervened and thus have been unable to make a precise diagnosis. It's definitely not mange, which has been documented once before in Bwindi. But it does last for weeks. To track this problem, Benard and I took dozens of photographs of the Rushegura Group infants, hoping that one of us would capture a decent image. I learned that it can be very dark in the Bwindi Forest, even on a clear day.

A view of Bwindi Impenetrable Forest from Nkuringo, Uganda.

After visiting the Rushegura Group, our plan was to visit another Buhoma-based family of mountain gorillas: Mabale Group. But the U.W.A. rangers reported that a black back (a young adult male gorilla) in the Nkuringo Group had been coughing. This group lives on the other side of Bwindi near the town of Nkuringo, a 15-kilometer (9-mile) forest walk from Buhoma. Unfortunately, the gorillas were another five kilometers away — too far to walk and do a health check on the same day. We got back in the car, drove five hours, spent the night in Kisoro, and drove another hour-and-a-half the next morning to Nkuringo.

To reach Nkuringo Group, we hiked down into a deep valley. Because of the dense vegetation, I found it difficult to fully observe each individual. But we did succeed in getting a clear view of the coughing black back, Kisoro. He rested most of the time, ate a bit and intermittently sounded a loud, dry cough. We were relieved to find that none of the other gorillas was coughing. Benard will go back to check in a few days. After a challenging hike out of the valley, I left with a new appreciation for the word "impenetrable."

[Uganda, Nov. 17, 2007. Pictures: Lucy Spelman/MGVP]

A Fragile Place

Friends Naomi and Robyn with ORTPN guide, Eugene watch Susa Group.

Last week, friends from the U.S. arrived for a long-planned visit. I've known one of them, Naomi, for more than 20 years. A classmate from vet school at University of California, Davis, she runs a small-animal practice in Aptos, Calif., rides dressage and lives on a small farm with her husband, Steve. Naomi has often traveled to visit me at work, but almost decided against this trip. After seeing the gorillas, she said, "I can't imagine why I hesitated for even a moment to come here!"

Robyn Kravit from Washington, D.C., the mastermind of the trip, brought her sister Nancy and two friends, Dave and Dennis. They met Naomi at the Brussels airport and the group of five flew to Kigali. Robyn arranged everything so that I could join them whenever possible. In Rwanda we toured the Genocide Memorial, trekked to see gorillas and golden monkeys, visited Dian Fossey’s grave site, and then drove to Uganda and hiked in Mgahinga National Park. Not only was the experience a lot of fun, it also gave me a fresh perspective on eco-tourism.

One of Susa Group's four silverback gorillas in November 2006.

I first trekked to see mountain gorillas a year ago as part of my initial job orientation, joining a tourist visit to Susa Group. I remember hiking three hours through the beautiful forest, encountering my first stinging nettles and wondering if we’d actually see any of my future patients. Then I caught a whiff of silverback — a strong musty smell. Seconds later an impressive male gorilla crossed the trail in front of me. I watched in awe for several minutes. Suddenly, I felt like an intruder and wanted to leave — I'd invaded his pristine world.

I felt too close for several other reasons. One undoubtedly had to do with my years as a clinical zoo vet: most Western lowland gorillas I’ve treated for one ailment or another do not remember me fondly. The other had to do with protecting the animals from human-borne illnesses, including the common cold. Though our tourist group was doing its best to keep the recommended 20-foot distance rule — if you cough or sneeze, the aerosolized droplets can’t carry that far — these gorillas walked right past us on the trail.

A juvenile in Amahoro Group has fresh mud on his lips from playing in a puddle.

Now I appreciate that closeness. If the gorillas weren’t habituated, they wouldn’t have doctors. Nor would we even know we had patients, let alone be able to treat them. The trackers are the eyes and ears of health care, because they can get so close. Since the gorillas don’t seem to mind a human presence, we vets can observe an injury closely. On the rare occasions when we need to dart an animal, we can minimize the stress because we don’t have to chase it.

Susa Group mountain gorillas playing, resting and foraging in November 2006.

Last week's visit to Susa Group with my friends reminded of how I’d felt a year ago. After a difficult hike, we caught up to the gorillas moving through a dense bamboo thicket. Several stopped to glance in our direction, others kept foraging and a female with a new baby sat down right next to us. My friends marveled at the experience. Why didn’t the gorillas mind our presence? The situation seemed so fragile.

Children tend cows on a farm near the Parc National des Volcans, Rwanda.

When you stand in the cultivated farmland that dominates the landscape around the Virungas, it's hard to imagine that an untouched wild animal habitat exists in this part of Africa. Once you're up there with the gorillas, you realize that it's possible to strike a balance between animals and people, even though the interface is a delicate one. Tourism brings in money that can benefit both, but it also carries risks in terms of disease transmission.

Genocide Memorial in Kigali, Rwanda.

Our visit to the Genocide Memorial was a sobering experience in every way, except for one: Rwandans do not hide the horrors of their recent past. The detailed exhibit tells the complete story of the 1994 genocide and its history. It also compares what happened in Rwanda to genocides in other countries. We agreed that the survival of the mountain gorilla was amazing, given the years of turmoil.

Dian Fossey is buried in Rwanda’s Parc National des Volcans,
as are many of the mountain gorillas she once studied.

At the request of Dian Fossey, MGVP (Mountain Gorilla Veterinary Project) was established a year after her death in 1986. But access to the gorillas over the next decade was limited because of the genocide. Even trackers based at Fossey’s research station had to leave the forest. Ultimately, all of her camp buildings were looted and destroyed. Only her grave site remains. The current fighting in the Democratic Republic of Congo has created a similar unstable situation in the Virungas. These days, no one can monitor the mountain gorillas on the Congolese side of the Rwandan border.

A golden monkey in Parc National des Volcans, Rwanda.

There are other fragile species in the Virungas that need protection, including the golden monkey. These rare and relatively unstudied animals are found only in the range of the mountain gorilla in areas where bamboo is plentiful. When my friends and I visited the golden monkeys last week, we saw dozens of them leaping above our heads from branch to branch, foraging for food. We don’t really know what threatens their health, beyond habitat loss. There is still so much to learn.

[Rwanda, Nov. 13, 2007. Pictures: Lucy Spelman/MGVP]

A Holistic Health Approach

A marshy clearing surrounded by bamboo in the
Sabinyo Group habitat, Parc National des Virungas, Rwanda.

When I was on a routine health check to Sabinyo Group last week, one of the trackers, Leonard, spotted a snare in the bamboo thicket to the right of the trail. It was a typical model: a rope tied at one end to a stalk of bamboo and made into a loop at the other end with a slipknot. This loop lies flat on the ground, a wooden stake holding it in place so that there is tension on the rope — enough to bend the bamboo horizontal. Leonard stuck the blade of his machete in the loop to spring the trap. Startled, I ducked just in time to miss the bamboo as it whipped back up. He untied the rope and put it in his pocket.

A bushbuck antelope disappears into thick vegetation.

Minutes ahead on the trail, another tracker, Jeanipo, found a second and a third snare; then Leonard a fourth. "Enough," I thought; "I don’t like these things. How can there be so many in a park that is highly patrolled and visited daily by scientists and tourists?"

So far, I've managed to photograph only the rear end of a bushbuck, but there's no question that the park is full of antelope. We see their tracks often. I asked Leonard and Jeanipo how many snares one would have to set to catch a bushbuck or a duiker (never mind a gorilla). The answer: five catches three. While the trackers made a radio call to the patrol team, I tried not to envision a dozen more Magayane cases.

An African elephant forages on bamboo in the
Group 13 habitat in the Parc National des Virungas, Rwanda.

We continued on the trail. Suddenly, several very fresh elephant tracks appeared. I held my breath, thinking we might actually see an elephant. That would be amazing luck, given that I've seen only one, three weeks ago on a routine visit to Group 13. I'd learned that day that elephants and gorillas sometimes travel together, often in the morning. But the huge prints disappeared from the trail after a short distance and my thoughts returned to the snares. They seem too small to harm such a huge animal, but I know of one elephant here that may have lost its trunk to a snare last year.

Gihishamwosti, a young male mountain gorilla in the Sabinyo Group,
has wounded toes on his left foot.

As we caught up to the Sabinyo Group, the gorillas left the bamboo area and crossed the marsh to a small water hole. Leonard announced that one of the young males, or black backs as they are called, Shirimpumu, had a wire snare around his toe last week. The gorilla had removed it himself, no problem. But while they gathered around the water, I noticed that another black back, Gihishamwosti, had a toe injury. He was missing two toenails on his left foot and his big toe was swollen. The problem was minor and very likely a random injury or a wound suffered in a fight. Then again, he too could have been caught in a snare for a short while.

As I understand it, gorillas rarely drink water for any length of time. But this group spent five minutes at the water hole. Watching them drink, my mind shifted to the issue of disease. We'd been talking earlier in the week about MGVP goals for the future and had agreed that the project should work harder to exchange information with local public health officials, district veterinarians and lab technicians in order to create a better network for alerts of disease outbreaks that could spread to the gorillas. One of the easiest routes of disease transmission is water.

Tourists visit a habituated mountain gorilla group in Rwanda, Park National des Virungas.

It's not always obvious to people why the mountain gorillas are at risk of disease or why they need vets. After all, the animals live in a protected area. But from an everything-is-connected or integrated health point of view, the gorillas are healthy only if the humans and animals in their ecosystem are also healthy. Thus, another of MGVP's future goals is to share the reasons for existing health regulations and to make recommendations to strengthen them if necessary. Tourists are asked to keep their distance, for example, because they've been in airports and crowded places. Even a common cold can make the gorillas sick.

Members of Pablo Group outside the Parc National des Virungas, Rwanda.

We also agreed that MGVP should continue to offer employee health screening programs for trackers, rangers, guides and scientists. There's every reason to screen this group of people carefully, considering that they spend hours with the gorillas. But the biggest challenge is how to protect the gorillas in the face of a disease outbreak in the villages near the park boundary. When the gorillas leave the park to forage for thistle or eucalyptus, there's always the chance that they may move into an area where flu or measles is active. We need better information exchange with health officials so that more people understand the risks.

A domestic cow inside Akagera National Park, Rwanda.

Cows can carry tuberculosis, brucellosis and a variety of intestinal parasites and bacteria that can be harmful to other animals and humans. When we went to Akagera Park last week, looking for the giraffe that whose snare we'd removed several months ago (Misson Giraffe), we saw cows everywhere, both inside and outside the park. Though the main focus of MGVP vets will always be gorillas, we also talked in our meeting about ways to improve domestic animal and livestock health. We agreed that another goal should be to help train more domestic animal vets in the region.

Giraffe, Akagera National Park, Rwanda

As for our giraffe patient, though we never found him, the rangers and guides reported seeing him a few days earlier. They said he looks a bit thin and still has a limp, but they described a wound that sounds as if it's healing slowly. His case underscores yet another need in this region — more trained wildlife vets. Again, this isn't something MGVP can do alone, but it can help by establishing a network of experts and helping when time and resources allow. We hear Akagera Park will soon hire its own vet. Maybe he or she can help us find our patient next time.

[Rwanda, Oct. 2, 2007. Pictures: Lucy Spelman/MGVP]

How to Identify a Mountain Gorilla

[Click on the pictures to see larger versions with captions.]

Inyongera (ee-yong-gara) sat up to reposition herself. The bright sunlight etched shadows into the wrinkled area above her nostrils, a pattern we refer to as a nose print. This pattern is unique to each mountain gorilla and serves as an identifying mark, like a thumbprint. I'd describe hers as a disjoined "Y," like a letter drawn with a magic marker during a bumpy car ride.

When the mother gorilla stretched out on her back, her infant, Byiringiro (ebee-rin-giro), ambled over from the clump of vegetation where he'd been playing. He climbed onto her belly for a nap. I couldn't see his nose print at that point, but I knew him by his mother. Unfortunately, his position also prevented me from seeing the reported swelling on his mother's lower abdomen, one of the reasons for my visit.

Though I keep a list of the mountain gorillas' names and a copy of their nose prints in the side pocket of my camera bag, I've by no means mastered the art of identification — and not only among the gorillas. It's taken me seven months just to learn the names of the many trackers who work in the Parc National Volcans (PNV). They, of course, know me as one of the Mountain Gorilla Veterinary Project (MGVP) field vets, since there are only seven of us serving all three countries, Uganda, the Democratic Republic of Congo and Rwanda. Moreover, I'm the only white woman among them.

I do know most of the gorilla names (about 280) and many of the adult gorillas. In Umubano group, for example, I know the silverback, Charles, and can make an educated guess about the mothers with infants; there are only so many choices in this small group. But when it comes to the confusing juveniles, subadults and black backs (young males) in the larger gorilla groups, I need help.

Even with the drawings of their nose prints in front of me, I cannot be entirely certain who is who among the healthy gorillas. Our patients, by contrast, almost always have distinctive features like a cut or a limp, or, as in Inyongera's case, swelling still hidden by her infant.

About 10 feet uphill from where we stood, another mother gorilla, Umurimo (oo-moo-reemo), rested in the sun with her as-yet-unnamed baby. (On June 30, the park's officials will name the 23 gorillas born in the past year.) Our lead tracker for the day, Leonadas, had noticed Umurimo moving slowly yesterday, and he felt she hadn't eaten normally.

Finding and identifying each group member, then reporting on their daily location and general health status is the job of the trackers. They locate the gorillas every morning, then relay the information to park headquarters. If there are tourists visiting, the guides bring them up the mountain. We usually go up with the trackers early — 6:30 a.m. at the park boundary — and do our vet checks first.

Today we adhered to the usual routine: Leonadas led us up the mountain to the group, about a one-hour climb. He methodically followed the trails made by each gorilla, leading us close and whispering their names. Then he'd stop and give us time to observe each one and take notes.

We first saw Umurimo high up in a tree eating favorite white flowers with her infant hanging on. We saw her again a bit later, moving quickly up a steep slope and eating as she went. Now, during the rest period, she looked the picture of health, her baby suckling loudly from time to time. Good news.

Inyongera had proved harder to find. We'd seen Byiringiro off by himself, playing with another infant. Where was his mother? Suddenly she appeared in front of me. I could see the abdominal swelling clearly, but didn't have my camera ready. We try to keep our distance from the gorillas, for their safety as much as ours (one of us could be carrying a flu or cold virus, for example). But sometimes the gorillas will walk right up to us.

In this case, the mother gorilla hesitated long enough for me to pull my camera out of the bag. But just as I hit the power button, I slid off a slippery log into a hole, nearly taking Elisabeth with me. Inyongera gave us a sidelong glance and continued on her way. We needed to get a better look and also record the problem photographically. Hers is a case in which pictures taken on different visits will be extremely useful. Vets in the field may have different opinions about the cause of swelling based on whether it's changed in size or appearance; the camera can document this information objectively.

When Inyongera settled down for a rest with her infant sleeping on her belly, we still hadn't gotten our picture. While we waited for one of them to move, I studied the nose prints of the two mother-infant pairs.

Umurimo's baby has barely developed a pattern; he's young and the marks on his nose will change over time. I'd describe Byiringiro's print as a series of shallow nestled "Vs" — hard to distinguish from those of other gorillas with similar V-shaped prints unless you see the nose up close. As for Umurimo, her nose print starts off as a wide "U" and ends in a deep "V," very different from the messy "Y" on Inyongera's nose. (There are "official" drawings of the nose prints for each known mountain gorilla, kept on file at park headquarters.)

Byiringiro got up to play with another infant. Finally, we could see his mother's abdomen and take our photos. The swelling looked more like an old umbilical hernia — and egg-sized accumulation of fatty tissue under the skin — than an active problem. Of course, it could be something serious, like an abscess or a tumor, but the gorilla appeared in perfect health otherwise.

Though I don't think we have to be concerned about Umurimo, we'll keep an eye on Inyongera for sure. One of us will be back tomorrow, and if it's me, I'll do my best to identify her among the group without Leonadas' help. If I can't, I know he won’t mind helping me. That's his job, after all.

[Rwanda, May 28, 2007. Pictures: Lucy Spelman/MGVP]