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Planet in Peril

Aired April 22, 2010 - 23:00   ET




ANDERSON COOPER, CNN HOST: We begin our journey here in central Africa, where rising food prices and a rapidly growing population are pushing people deeper and deeper into previously untouched forests. They're just trying to make a living, of course, clearing land, hunting for food.

The problem is not only are their threatening fragile habitats and wiping out animal populations at an alarming rate they're also exposing themselves to potentially deadly viruses. Viruses which once unleashed in humans can quickly spread around the world. These forests may seem remote, but what's happening here now affects us all.

(voice-over): January 2008. Rising food prices touch off riots around the world. In Haiti, ten people died. In Cameroon, 20 are killed. Unable to afford basic supplies, people increasingly turn to the forest for food. June 2008. Deep in a remote region of Cameroon, two hunters stalk their prey.

Their names are Patrice (ph) and Patee (ph), they're searching for bush meat, forest animals they can kill to feed their families.

(on camera): Patrice and Patee set most days to go out hunting in the forests around their homes. They have a series of straps of snares that they've set up, and they'll catch wild pigs, snakes, monkeys, rodents, anything they can, really.

(voice-over): Patrice and Patee have been out for hours, but found nothing. The animals are simply gone. Not too far away, Dr. Sanjay Gupta is with another hunter. But he, too, is finding his traps empty.

DR. SANJAY GUPTA, CNN CHIEF MEDICAL CORRESPONDENT: Really gives you an idea of just how hard it is to actually get even a little bit of food. Diddy, who is trying to provide enough food for nine people tonight, doesn't really care what he gets at this point, as long as he gets something, and I can tell you we've still got a long ways to go. It is hot, it is humid, it is a lot of work.

COOPER: Hunters have to keep going deeper into the forest, but that is where hidden danger lurks. Forest animals are a reservoir of viruses, microscopic pathogens living in the animals' blood. Some are harmless, but some are potentially deadly when passed to humans.

DR. NATHAN WOLFE, EPIDEMIOLOGIST: Individuals have been infected with these viruses forever. What's changed, though, is in the past, you had smaller human populations. Viruses would infect them and possibly go extinct. Viruses actually need population density as fuel.

COOPER: Dr. Nathan Wolfe is a world-renowned epidemiologist, a virus hunter. He works in these forests, tracking what are called zoonotic viruses; ones that can jump from animals to humans. It's the zoonotic viruses that scientists think could trigger the next pandemic.

WOLFE: When I look around in this forest, part of -- part of what I'm thinking is what's the diversity of viruses out there?

COOPER: It may sound far-fetched, but it's already happen. HIV is the deadliest example.

(on camera): It was in a forest not too far from here in southern Cameroon that scientists now believe HIV was born. They say it started with a chimpanzee infected by several strains of viruses from eating smaller monkeys. An infected chimp's blood then must have come in contact with the blood of a human being, most likely say scientist a hunter or someone cutting up the chimp for cooking.

That simple, seemingly insignificant transmission set off a global epidemic, a pandemic that so far has killed tens of millions of people. Scientists now believe HIV crossed into humans in the early 1900s, but it wasn't until air travel increased that it spread and became a global epidemic in the 1980s.

(on camera): Is it inevitable that there will be another pandemic of some virus like HIV?

WOLFE: Yes. The human population is going to have pandemics. That's just the nature of how we operate now. We are so profoundly interconnected that it will be the case that things will enter into the human population and they'll spread globally.

COOPER: HIV may be the most well-known virus to cross over from an animal to a human, but there are many others, and many we don't even know about. That's why Wolfe has created what he calls a global viral forecasting initiative, a kind of early warning system in virus hot spots around the world to track the transmission of viruses.

He's worked in Cameroon for nearly a decade, monitoring hunters and those who butcher bush meat; both activities where human and animal blood are constantly in contact. Dr. Wolfe likens his work to the way an intelligence service tracks threats made by potential terrorists. If he can track what viruses are crossing into humans, what he calls the viral chatter, he hopes to stop the next virus before it spreads.

WOLFE: Each one of those species of animals has their own sort of repertoire of different organisms, viruses, parasites, bacteria. And anytime that humans are in contact with those animals, there's going to be the possibility for the jump-overs.

And that's what we're kind of considering this sort of chatter, this pinging, if you will, of viruses from these animals into the human population. And most of the time the ping just bounces back, but every once in a while it sticks.

COOPER: It's sticking more often. The National Academy of Sciences says 75 percent of the world's emerging diseases jump over from animals.

The SARS virus crossed from civet cats in Asia to infect thousands and killed more than 700 people in more than 20 countries. Avian flu jumped over from birds around 2003 and killed more than 200 people.

The origins of many others zoonotic viruses are still unknown. Ebola has killed hundreds over the past decade, but its exact origins remain a mystery. If scientists don't know where a disease starts, it usually means it can't be stopped.

It's been hours in the forest for both our teams, chasing prey that seems to vanish. We stop for a drink of water. Then there's a rustle in the brush. A group of hunters approach.



COOPER: Their packs loaded with wild game.

(on camera): There is at least three viruses that you know about which are in this particular monkey.

WOLFE: This species, yes. And there's many, many more pathogens that are present in these animals.




COOPER: In the forests of Cameroon, Dr. Sanjay Gupta and I have split up. We're both following men hunting for animals or bush meat.



COOPER: Patrice and Patee, the two hunters we've been waiting for the couple of hours haven't been able to find any game today. They've been unlucky, but we did came across these group of hunters who have several packs full of animals that they've caught.

WOLFE: This monkey potentially is infected with retroviruses. COOPER: But virus hunter, Dr. Nathan Wolfe, is concerned about what unknown viruses these animals might carry, viruses that could make their way into the human population, touching off a pandemic.

(on camera): There is at least three viruses that you know about which are in this particular monkey?

WOLFE: In this species, yes, yes. Yes, I mean, there's many, many more pathogens that are present in these animals. These individuals are at specific risk, particularly depending on the level of contact. If there's blood contact, they're at risk for transmission and possibly infection with novel viruses.

COOPER: As the hunters display their kills, something surprising happens. They show us filter paper they've used to collect the animal's blood. The blood will be tested for zoonotic viruses, part of a program Dr. Wolfe has spent years setting up.

Does it surprise you that I mean, we've run into two groups of hunters out here and they're all carrying the filter paper that you have been teaching them about?

WOLFE: Yes -- no I mean, from our perspective, it's a good indication of the coverage we have. So this is from this animal right here. Greater spot-nosed guenon (ph) these individuals, every person who has one of those filter papers has had -- at least at a minimum been through our basic health education about the risks associated with these activities. Which, presumably, from our perspective, gives them the ability to decrease their own risk and then, obviously, the risk to their families, the village, the country, and the world.

COOPER (voice-over): Once bush meat is taken out of the forest, you can find it for sale everywhere. On the side of the road, there's pangolin for sale, snakes, monkeys, and markets selling bush meat are packed with people.

GUPTA: Would you check the blood of these -- these monkeys at all?

WOLFE: Absolutely.

COOPER: Dr. Wolfe estimates 4.5 million tons of bush meat are taken from central Africa's forests every year. A task force of leading conservation groups says the bush meat trade is the single biggest threat to Africa's animal species, and that's making it more of a threat to humans.

WOLFE: Contact with some animal in this remote village that previously might have led to the jump of a virus into that community, that would have maybe infected a few people, maybe infected one person, probably would have died out.

Now, all of a sudden, that remote village is immediately connected to the major city and through air transportation and ships, through the rest of the world. So something that's in the middle of nowhere, here, for example, can potentially, you know, be in New York in the course of 48 hours --

UNIDENTIFIED FEMALE: Health officials aren't sure how many animals or humans might be --

UNIDENTIFIED MALE: -- jumped to more than 30 humans.

UNIDENTIFIED MALE: There may be other individuals with ill animals.

COOPER: In 2003, Americans were shocked when a rare zoonotic disease called monkeypox infected dozens of people in the Midwest.

UNIDENTIFIED MALE: So far the disease has spread to Wisconsin, Illinois, and Indiana.

UNIDENTIFIED FEMALE: Symptoms like fever --

COOPER: It turns out it was caused by African rodents imported into America as pets. That outbreak was quickly contained. But in Central Africa, monkeypox continues to kill.

Dr. Wolfe takes Sanjay and me on a long journey from Cameroon to the Democratic Republic of Congo, where 20 people have just died from a monkeypox outbreak.

We fly to a remote town called Loja, where in a walled compound we find Coy, alone in a small hut.

GUPTA: Now, we're standing out here and she's inside there. Why is that?

NEVIL KISALU, LOCAL SCIENTIST: So the first thing we need to do is isolate the patient.

COOPER: Neville Kisalu is a local scientist, working with Dr. Wolfe's team.

GUPTA: Are we at risk? I mean, how contagious is this?

KISALU: Just looking at the patient, you have no risk. But when you are in contact -- direct contact with the patient, at that time, you are in danger.

COOPER: Coy is the latest victim. All of these people are slowly recovering and are still quarantined in this makeshift clinic. Painful sores cover their bodies and they say they feel tired all the time.

GUPTA: If she hadn't made it to you, to this place, what would happen to her?

KISALU: Some patients recover, but others die.

COOPER: Coy probably got monkeypox through contact with bush meat, which she says she handled over the past few weeks. Or she came in contact with an infected person. Its exact origins are still unknown. It's unlikely monkeypox could become a pandemic, because it loses strength as it passes from person to person, unlike HIV.

Coy will have to stay quarantined for weeks. There's little the medical team can do for her aside from hoping the monkeypox runs its course and she survives. For Dr. Wolfe, Coy's case is both a warning and a sign of things to come.

WOLFE: We're just tapping the surface. We've got the tip of the iceberg when it comes to our knowledge of the different viruses that are out there. And by documenting them, potentially to get in a space where we can prevent pandemics instead of waiting for AIDS to happen and spread globally, to actually catch it earlier, which could potentially save millions of lives.


COOPER: Great white sharks are the most feared animals on the planet, but there's a lot we still don't know about them. In order to understand them better, some people believe you need to study them up close, actually get in the water with them.

But it's a controversial idea. Critics say that actually encourages sharks to attack humans and makes them more dangerous. We decided to get in the water for ourselves and find out.


(voice-over): When great white sharks start to circle your boat, the feeling is unsettling. Fifteen feet long, thousands of pounds, these are the animals of so many nightmares.

WOLFE: This is fighting the shark.

COOPER: We've come to dive with these great whites, to get an up close look at them and the battle that's being waged around them.

MIKE RUTZEN: Please, do not go down unless we tell you to.

COOPER: Mike Rutzen takes tourists cage diving with great white sharks off the coast of South Africa.

RUTZEN: And then you can lean back and hold on and be comfortable.

COOPER: It's become a big business, but it's also, he says, a conservation effort. He thinks if people can see these great endangered animals underwater, they'll learn to appreciate them and want to help protect them.

Cage diving, however, is highly controversial. We'll tell you why in a second, but right now the water is filled with blood and fish parts called chum and the great whites have arrived.

So, any recommendations for what to do?

RUTZEN: Well, basically, don't scare the sharks. You're going to the water -- COOPER: I'm not worried about scaring the sharks. It's usually the other way around, I think.

After we get used to being in the water with the sharks inside a cage, we had the chance to do something that few others ever have. We'll go swimming with great white sharks without a cage.




COOPER (voice-over): Climbing into a shark cage is scary. The sea is chummed with blood and fish parts, and underwater visibility is low. At first, all you see is a vague shape moving fast. Then, all of a sudden, you find yourself face to face with a great white shark. Its mouth open, its eyes rolling back into its head.

(on camera): It's one thing to see a great white shark from the boat, but to actually be down in the water; to be, you know, 6, 7 feet away from one, it's an extraordinary experience.

(voice-over): This experience has become a major draw for tourists. Each one of these people paid $150 to visit this reef off the coast of South Africa known as Shark Alley.

It's one of the best places in the world to see great whites and shark tourists bring in more than $30 million every year to South Africa.

But is this really good for sharks? The battle lines are drawn. At issue is how the sharks are brought to the boat -- chumming; mashed up fish parts and blood are thrown into the water and the scent attracts the great whites.

Once the sharks arrive, a tuna head attached to a rope is used as bait to lure the sharks to the surface and get them to lunge at the cage.

RUTZEN: The bite's just a visual reference to the smell. So all we're doing is, we don't let it take the bait, we're just pulling it and trying to pull the bait a little bit closer that the animal can turn and come a little bit closer to the cage, that the people can see a little bit better.

COOPER: But it does sometimes get the bait?

RUTZEN: It does sometimes get the bait. Yes, and that's unfortunate.

COOPER: Critics say it's more than unfortunate, they say it's dangerous. When the sharks gets the bait, it teaches them to associate food with humans in the water. And that, some locals believe, is encouraging great whites to try to eat swimmers and surfers. Craig Bovem (ph) thinks cage diving could be why a great white almost killed him. Bovem was diving for lobster on this beach near Cape Town in 2005 when he was attacked.

CRAIG BOVEM, VICTIM OF SHARK ATTACK: He just clamped on -- on both my arms. When I came out of that impact, I was still inside his mouth and he was slowly swimming with me.

COOPER: The shark was dragging him out to sea. After he overcame the shock of what was happening to him, he began to fight back.

BOVEM: So I started putting my knees into his belly and I saw that that was having some effect on him and I head butted him with my mask on his nose and carried on this tussle for quite a while.

COOPER: So basically you were wrestling with a shark underwater?

BOVEM: Yes, and I realized I wasn't actually getting up so just pulled on my right hand. And I thought I was going to leave my hand inside him and I pulled and pulled and eventually my arm came free.

COOPER: So this bite here --


COOPER: Both of Bovem's hands were mangled and his right one is permanently damaged. Today, he still surfs and dives in the same water where he was attacked, but he's become one of the cage diving and chumming's most vocal critics.

BOVEM: You cannot find a single example of people feeding and attracting and baiting animals that has been successful. It's a no- no.

COOPER: With no other animal viewing do people bait or chum. I mean, to go see a lion, you don't throw out food.

BOVEM: They used to. Nobody would even think about doing that anymore.

COOPER: Shark tour operators can't do it anymore in Florida and Hawaii. After a serious of vicious shark attacks, chumming was banned in both states. But shark tour operators in South Africa point out that even though shark tourism has risen dramatically in the past decade, shark attacks have not.

On average, there are around five attacks on humans every year in South Africa. But Craig Bovem and others insist the behavior of sharks is changing, normally if a shark bites a human they released them. But the shark that attacked Bovem did not. And in the last four years there have been at least two deadly attacks in which sharks ate their victims, whole.

So who's right? Unfortunately, the science to support either position isn't easy to come by. For all our fear and fascination with great whites, they remain a mystery. There's so much we simply don't know about their behavior. They've never been seen mating or giving birth, for example. And though they're classified as an endangered species, we don't even know how many of them there are.

Allison Koch is a marine biologist studying the effects of cage diving on the feeding habits of great whites. Koch is tagging great whites with darts attached to transmitters. She can then track the shark's movements around these waters for months.

ALLISON KOCH, MARINE BIOLOGIST: Here we go. Here we go. Keep it there. Keep it there. Tagged.

COOPER: She's tagged over 70 sharks so far. The data she's collected led to the only peer reviewed study on the effects of cage diving on shark behavior.

KOCH: The study that we did showed a surprising result in that the sharks, most of them stopped responding over time to the boats.

COOPER: So you don't see any connection between increased shark attacks in this area and shark tourism?

KOCH: No. Not at all. All the evidence that we have at the moment finds no link between chumming and shark attacks. We're definitely not on the sharks' menu.

COOPER: Mike Rutzen's so sure we're not on the sharks' menu, he stakes his life on it. He's one of the few people in the world willing to swim with great white sharks without a cage. He's been doing it now for ten years.

He believes to understand the true nature of great whites, you have to do it without a cage. You have to meet the animal on its own terms.

So we decided to join Rutzen under water so we too can come face to face with this most feared predator of the sea without a cage.

(on camera): It definitely gets your heart beating.


JOE JOHNS, CNN CORRESPONDENT: I'm Joe Johns. PLANET IN PERIL will continue in a moment, but first the top Earth Day headlines at this hour.

A severe weather threat has residents on alert across the plains from Nebraska to Texas tonight and tomorrow across the southeast. Forecasters say violent thunderstorms and tornados are possible.

The oil rig that exploded in the Gulf of Mexico is gone. It sank today with hundreds of thousands of gallons of oil now leaking into the sea. Eleven people are still missing in that disaster.

The chemistry of the oceans is changing rapidly. That's according to the National Research Council. It says carbon dioxide and other industrial gases are being taken up by the oceans. Those chemicals can make the water more acidic, which can impact sea life.

And here's the sun like you've never seen it before. These are high-definition images from a new NASA telescope showing a massive solar flare with the power of 100 hydrogen bombs. The Solar Dynamics Observatory will collect data for the next five years and could give fresh insight into how the sun works.

Those are the Earth Day headlines.

Back to PLANET IN PERIL in a moment.



COOPER (voice-over): Preparing to swim with great white sharks without a cage produces two reactions. The first is -- well, fear. It's hard to believe you're about to actually do this.

The second reaction is a surge of adrenaline.

(on camera): It definitely gets your heart beating.

(voice-over): Mike Rutzen knows that better than anyone. He's dived with great whites without a cage hundreds of times. He once even caught a ride on a great white's dorsal fin. He insists these animals may be top predators, but they're not the man-eating machines so often portrayed in movies.

We have decided to take him up on his offer to dive with the sharks without a cage to see the great whites in their natural state.

(on camera): What do I need to know before going down?

RUTZEN: Whatever you do, don't make fast movements. What we are is the same as a jackal at a lion feed. As long as the jackal behaves, it doesn't get killed.

COOPER: So, we're like the jackal at a lion feed? The great white are the lions, and we're the jackals?

RUTZEN: Exactly.

COOPER: They will let us be there, as long as we don't interfere with them?

RUTZEN: Don't try and grab a bone and run away.

COOPER (voice-over): The water is filled with chum, fish parts and blood. A number of sharks are already circling the boat. So, it's time to go.

To get to the bottom, I climb into a cage which is lowered about 20 feet to the ocean floor. Mike's already there, scouting for any sharks. Then, he signals for me to swim out. Almost immediately, my weight belt falls off. Struggling with that is the last thing you want to be doing around great whites. The current is really strong. And Mike has me hold on to a rock to stay in place. Visibility is low.

But then, suddenly, the sharks come into view. It's clear they see us, but they're keeping their distance, gliding by slowly, gracefully. It's remarkable to see them like this, to be so exposed to an animal that is so feared.

Mike warned me they don't like the sound of air bubbles and told me to hold my breath when they got near. Truth is, my heart's pounding so fast, holding my breath is almost impossible.

At one point, there are four different sharks swimming around us. It's important to stay alert. But, after a while, I'm also able to appreciate the beauty, the power of these animals, widely-hunted, universally-despised, capable of such destruction. And, yet, when you see them like this, not lunging after bait, but simply gliding through the water, you see them in a different way. You understand there is more to them than we know.

We stay down for more than 30 minutes, until our oxygen nearly runs out.

(on camera): To see it so close, just -- I have never seen anything like it.


COOPER: It's amazing.

RUTZEN: You're still alive, eh?


COOPER: Yes. That was great. Thank you.


COOPER: That's pretty amazing.

You get a totally different sense of them, seeing them like that versus seeing from a cage, where they're attacking a piece of bait.

RUTZEN: They're just trying to be sharks.

COOPER (voice-over): They're just trying to be sharks.

But the truth is, we really don't know enough about what that means. As long as our knowledge of sharks and the role they play in our oceans is dwarfed by our fear and our hatred of them, the fight over their future will go on.


UNIDENTIFIED MALE: Next on PLANET IN PERIL, mountain gorillas.


COOPER (on camera): We've been hiking already for nearly two hours. We're not sure how much further up the gorillas are.


UNIDENTIFIED MALE: How the animals and a country help to bring each other back from the brink.


COOPER: The list of threats to our planet are almost too many to count: species lost, habitat destruction, climate change. But there are success stories. Like what's happening in Rwanda. It's there in the forest that the endangered mountain gorillas are thriving and bringing hope to an entire country.


COOPER (voice-over): You hear them before you see them: snapping branches, deep grunts. They are the world's last remaining mountain gorillas. Massive and magnificent, they are cautious but incredibly curious.

There are only about 720 of them left on the planet, all of them living in the forest that straddles Rwanda, Uganda, and the Democratic Republic of Congo. They're considered critically endangered; on the brink of extinction.

But in Rwanda, the survival of the gorillas has become a case study in how a country benefits from protecting its natural resources, instead of destroying them.

It is a success story in one of the most unlikely places on earth. Just 14 years ago, Rwanda was in chaos, as one ethnic group tried to exterminate another. Neighbors killed neighbors. It was a genocidal blood bath resulting in the deaths of nearly 1 million people.

Since then, Rwanda has emerged from the violence and looked for ways to rebuild, looked for signs of hope. They found it in the forest. They found it in the gorillas.

(on camera): Why was it important for you to come back here after the genocide?

UNIDENTIFIED MALE: To come to see the animal, to see the gorillas.

COOPER (voice-over): There were still armed militia roving this area when Darawana Francois (ph), a park ranger and guide, risked his life to check on the gorillas just after the genocide in 1994. He took us to the spot where he entered Rwanda's Volcanoes National Park during those dangerous days. UNIDENTIFIED MALE: I have one group of thirteen. You know group of thirteen. I visited first time. And the silverbacks is dying because the problem, the people killed the silverback.

COOPER (on camera): During the genocide?

UNIDENTIFIED MALE: The genocide, yes.

COOPER: What is that like, to see one of the gorillas dead? What is it like for you?

UNIDENTIFIED MALE: Was sad. It was a problem. Cause he die. For me was -- it is the same as your children. Your children you see die, or your wife see die. You sad.

COOPER: Seeing a gorilla die is like seeing a member of your family die.


COOPER (voice-over): The problem for the gorillas for decades was that they were hunted and sold to zoos or killed as trophies. Local poachers also set snares for other animals that the gorillas got caught in.

After the genocide ended, a new government took over, and they decided to get serious about protecting the mountain gorillas. Essentially, they gambled they could pull the country and a species back from the brink simultaneously. They decided to put the gorillas at the center of their tourism effort.

For regular Rwandans, however, it was a tough sell. Rosette Ragumba (ph) is Rwanda's head of parks and tourism.

ROSETTE RAGUMBA, HEAD OF PARKS & TOURISM, RWANDA: The community was very antagonistic. They really did not understand. And you can't blame them, because why should they protect the gorillas? What does it mean to them?

UNIDENTIFIED MALE: See the sign of the gorillas (ph) over there.

COOPER: No one seems to ask that question anymore.

In 2007, more than 13,000 tourists paid up to $500 to spend one hour with some of the gorilla families that have been habituated to humans by scientists. Tourism is now the country's third largest generator of foreign capital.

Five percent of the $7 million the government earned last year from gorilla tourism went back to the communities near the gorilla's habitat. It's used to build roads, schools, and health clinics. Local people now see a benefit to keeping the gorillas alive. And in Rwanda, the animals themselves are thriving.

Next door, however, it's another story. About half of the world's last remaining mountain gorillas live in forests in Rwanda's neighbor, the Democratic Republic of Congo. Just last year, ten gorillas there were slaughtered, shot to death. Some were even set on fire.

Congo has been battered by civil war for more than a decade now and some $5 million have died as a result. The gorilla's habitat is literally a battleground. So unstable, rangers can't even enter the forest to patrol and protect them.

(on camera): There's nine gorillas in this group.

(voice-over): During a lull in the fighting, we visited Congo's gorillas in 2006. But today, no one is sure if these same gorillas are even alive.

That uncertainty makes the protection of Rwanda's gorillas all the more important.

Veronica Verselio (ph) has been monitoring Rwanda's gorilla groups for more than three years as director of research with the Dian Fossey Foundation. We're hiking with her up a steep mountain to go and see what's called a research group, gorillas never visited by tourists.

(on camera): We're not exactly sure what to expect.

The scientists who study these gorillas said there's a lot of aggression in the group, and they're not really sure how they'll react to our presence. So, frankly if they charge, I'm going to hide behind the biggest cameraman I can find.

UNIDENTIFIED MALE: These are fresh tracks.




COOPER (voice-over): Deep in Rwanda's Volcanoes National Park, we're hiking high in the mountain to see an animal threatened by conflict on the brink of extinction.

(on camera): We've been hiking already for nearly two hours. We're not sure how much further up the gorillas are. We're heading to a group of mountain gorillas which have never been visited before by tourists. They're not habituated in the same way. They've only been studied by scientists.

Before we enter the park, Veronica, the wildlife biologist, was telling us there's a lot of aggression in this group of gorillas that we're going to visit. So it should be interesting.

(voice-over): Gorillas are always on the move, searching for food and a place to rest. Trackers have gone up ahead of us to locate the family and radio us the coordinates. But even with the extra help, finding them isn't easy. Nearly three hours into the hike, there are signs we're finally getting close. We finally find them in a large clearing and come face-to-face with one of the families blackbacks, a young male.

Our trackers grunt, signaling we're not a threat, and he lets us go by.

It's an amazing sight: 43 gorillas in a single spot in the forest, about 20 percent of Rwanda's entire gorilla population. This family is called the Pablo group, named after the male silverback who used to be in charge. Pablo is still around, but another silverback, Cansby (ph), is now the boss.

(on camera): That's the silverback. That's the adult male?

VERONICA VECELLIO, DIAN FOSSEY FOUNDATION: That's the dominant silverback.

COOPER (voice-over): An adult male can weigh about 400 pounds and eats up to 60 pounds of vegetation a day.

VECELLIO: She transferred from one of the tourist groups.

COOPER: A biologist and director of data and research of the Dian Fossey Foundation, Veronica Vecellio (ph) studies Rwanda's three research groups.

(on camera): What's the value of having a group that's not a tourist group, that's just a research group?

VECELLIO: Continuing the research in gorillas is very important. It always gives a lot of information in terms of population dynamics.

COOPER (voice-over): Population dynamics are important, especially since there are only about 720 mountain gorillas left in the wild, and they're smack dab in one of the world's worst conflict zones. Even the gorillas seem to know it.

(on camera): You have a Congo border, and there's obviously so much instability in Congo. How does that impact the gorillas?

VECELLIO: The gorillas, they are pretty much obliged to stay in Rwanda. They try several times to move her and to cross the border. And after a few hours, they run away -- literally, they run away and they come back to Rwanda.

COOPER (voice-over): We've been here for about an hour, and Cansby (ph) and the others don't seem to mind our presence. Frankly, they seem a little bored with us.

(on camera): We were warned that these mountain gorillas might be aggressive toward us, because there are so many adult males in the group and because they're not used to having so many visitors. Veronica is telling us that it's been raining a lot at night, and it's particularly cold. So a lot of these mountain gorillas are just exhausted, and they're just going to sleep through the day. (voice-over): Because gorillas can catch human diseases --

VECELLIO: How many minutes for the next --

COOPER: -- scientists limit the time they spend with them. So after only an hour and a half, it's time for us to go.

(on camera): What we're doing is kind of looking -- going around the world looking at places where man is in conflict with nature and with natural resources and animals. It seems like Rwanda is a success story in many ways.

VECELLIO: Yes, yes. Definitely it is. There's still a lot of conflict, but there's a lot of Rwandans that they really care about the protection of the gorillas and I think they're the most beautiful success of conservation of mountain gorillas. Trust (ph) the local people to take care of their own natural resource.

COOPER (voice-over): This is a species still teetering on brink. But Rwanda's protection of these mountain gorillas is a lesson that conservation is possible. Even on the battle lines.


COOPER: Over the next 40 years, the human population is expected to rise by 50 percent and yet already many of our natural resources are dwindling.

Recently, the U.S. director of national intelligence said that, over roughly the next decade, competition for those resources will likely lead to increased global conflict.

The question governments around the world have to answer now is how best to preserve the resources we have left through conservation and innovation and technology.

If you want more information, go to

I'm Anderson Cooper. Thanks for watching this Earth Day special of PLANET IN PERIL.