Fifty years ago, on September 24, 1967, American Dian Fossey flew to Rwanda to study the country’s gravely threatened mountain gorillas. She hiked into the Virunga Mountains, pitched two tents and established the Karisoke Research Center. Fossey’s zealous work captivated the world, and she is widely credited with saving mountain gorillas from extinction. Although she was murdered in 1985 under still-mysterious circumstances, her legacy persists. Fifty years later Karisoke is now the longest-running gorilla research program, operated by the nonprofit Dian Fossey Gorilla Fund International.

Dr. Tara Stoinski is a leading primatologist and serves as President and CEO/Chief Scientific Officer at the Dian Fossey Gorilla Fund International, based at Zoo Atlanta. Credit: Dian Fossey Gorilla Fund

Today the work at Karisoke still focuses on the mountain gorilla—but now its researchers have also turned their attention to its close cousin, the Grauer’s gorilla. This subspecies lives in the Democratic Republic of the Congo and is quickly vanishing from the forest. If nothing is done, Grauer’s gorillas could go extinct within the next decade, says primatologist Tara Stoinski. Scientific American spoke with Stoinski, who is the president, CEO and chief scientific officer of the Gorilla Fund, about the status of Fossey’s mountain gorillas and Grauer’s gorillas, the threats facing both animals and how conservation efforts can help save them from extinction.

[An edited transcript of the interview follows.]

What is the status of Fossey's mountain gorillas?
Fifty years ago this month Dian Fossey established Karisoke [Research Center]. It was thought at the time that mountain gorillas might go extinct by the year 2000. But instead their population has doubled. In the region where Dian worked, they’ve gone from 240 individuals to 480.

It’s a great conservation success story, but the population is still incredibly fragile. There’s another small population of 400 individuals [in Uganda], so that means that on the entire planet, there are fewer than 900 mountain gorillas remaining. They’re one of the most endangered mammals on the planet. We hear a lot about elephants—for good reason, because they’re being decimated through poaching—but there are still [hundreds of thousands of] elephants left, and we’re talking about fewer than 900 mountain gorillas. So it puts in perspective how small and fragile this population is.

Are the threats mountain gorillas face now the same as those they encountered 50 years ago?
One of the major threats for mountain gorillas in Dian Fossey’s time was poaching, primarily for souvenirs. People thought it was cool to have a gorilla hand as an ashtray or a gorilla head on their mantelpiece. There was also poaching of infants. Luckily those are not problems for the mountain gorillas anymore—direct poaching has pretty much stopped. The biggest risk now is that they have a very small habitat. They live in a region that has some of the highest population densities in Africa. They’re restricted to a small area, so there’s risk of disease transmission because they’re very susceptible to human diseases. And people, even though they aren’t poaching [these] gorillas, still depend on the forest—they go and hunt other animals, like antelope, and gorillas can get caught in the snares as a result.

What kind of work happens now at Karisoke?
Our organization has 160 staff in Africa—115 in Rwanda and 45 in the Congo. They are the ones out on the ground every day. They’re continuing to collect those data that started back with Fossey 50 years ago. Karisoke is now the longest-running gorilla research program in the world, and a lot of what we know about gorillas in general has come from research done there. If there’s a question asked about gorillas, we’ve probably studied it. It’s not only helping us understand gorillas in general, it’s also really critical data that’s used to make effective conservation strategies. We collect data on health status, on whom has been born, whom has died and if individuals have moved between groups. If individuals go missing, we organize search parties to go look for them. So every single day we have our eyes on these animals, and we maintain this long-term database that’s invaluable for the scientific community.

In addition to studying and protecting the mountain gorillas, you have also turned your attention to their close cousins—Grauer’s gorillas. What is their status?
Grauer’s gorillas are another subspecies of gorilla—they’re found just over the border in eastern Congo. It’s the only country in which they’re found. They’re kind of in the situation that mountain gorillas were in 50 years ago, where their population is declining rapidly. We estimate that we’ve lost 80 percent of Grauer’s gorillas in the last 20 years. That means four out of every five has disappeared within two decades. Unless that rate of decline changes, they will probably be extinct within the next decade.

What threats do Grauer’s gorillas face?
Direct poaching—they’re hunted for food.

Unlike with mountain gorillas, where the habitat is so restricted and they’re kind of stuck at the top of volcanoes, Grauer’s gorillas live in areas where there’s still huge, beautiful, pristine forest. But the biggest challenge is hunting, much of which is driven by illegal mining in the area. These mines are in the forest, and there aren’t grocery stores in the middle of the forest, so to feed the miners, they hunt. These areas have what we call “empty forest syndrome,” where you’ve got the beautiful forest but the wildlife has been emptied out through hunting.

Is poaching different today, compared to what Fossey's mountain gorillas dealt with?
The level and sophistication of hunting that’s happening now with Grauer’s gorillas is not what Fossey’s gorillas experienced—back then it was a lower level and a lot of it was done with spears. It was not nearly as organized and there weren’t as many people in the forest. With Grauer’s gorillas, we’re seeing well-armed people who are hunting with guns and other weapons, so the impact they can have on gorilla populations is much more significant.

What are Grauer’s gorillas like? What do we know about them?
They’re probably the least understood of all the four types of gorilla, so we still have a lot to learn about them. So we’re just trying to gather the basics right now: What’s their group structure like? What do they eat? How big are their home ranges? The basic questions you need to understand and formulate conservation strategies. You have to know how much space a group takes up to know how much space you need to conserve in order to make sure they have a healthy population.

In terms of physical differences, Grauer’s gorillas are not as hairy as mountain gorillas. Because mountain gorillas live at such high elevations, they have very thick coats of hair to keep them warm. Grauer’s gorillas also lack the distinctive nose print that we see in mountain gorillas, which is one of the ways that Dian Fossey originally identified individuals. Their faces are a little bit longer. For a long time it was thought they were the largest of the gorillas, but more data are needed to say if that is actually the case.

Another big difference is that the mountain gorillas are habituated to humans, which means we can sit and watch them. That’s not the case with most of the Grauer’s gorillas we work with. There are some habituated ones, but in the area where we work, because poaching is such a threat, we don’t want them to lose their fear of humans. So we always follow them one day behind—you’re following their trails, recording their range, gathering poop samples to figure out what they’re eating and doing genetic analyses. You can even look at stress hormone levels. It’s a very different model of observing them than what we do in Rwanda.

What are you and others doing to keep Grauer’s gorillas from going extinct?
The biggest thing we need in conservation is boots on the ground—people out there in the forest protecting these animals. We’ve been able to clearly show with mountain gorillas that this is what has made the difference. The huge, concerted effort by governments and NGOs [nongovernmental organizations] has resulted in the mountain gorillas’ numbers increasing. Unfortunately most protected zones in Africa and other places don’t have that level of protection. And a lot of Grauer’s gorillas live in community forests, where they don’t have any formal protection.

What we’ve been doing is working with some of these community forests that are located between the two big national parks, where Grauer’s gorillas are found, to protect these animals. We’re working with local landowners—people who own forests, which still have gorillas, chimpanzees and lots of other animals—to get them to conserve and agree not to hunt these endangered species. As part of that, they’re hired as trackers, we help send their children to school and we try to help with livelihood development and food security. It’s a holistic approach that includes providing direct protection in the forest [for gorillas] as well as working with the local communities to try to address some of the reasons that gorillas and other animals are hunted in the first place.