a by invisible river that flows through the sky. starts march 23rd on d w. ah, ah, mountain gorillas have been on the brink of extinction, but are the only primates currently increasing in number? reaching the milestone, 1000 gorillas has been remarkable. so it's extremely good news. but while the mountain gorilla population increases, what happens when their habitat does not grow with them? that book is that thought there are far more cases of guerrilla groups attacking each other than there used to be with fatalities on a regular basis. yeah. your us, this is something from one into group faith and that is, i think one thing we wanted to know whether the stress levels are increasing. if we don't like to know, we at risk of not being able to do it in 10 years, for example, from now. conservationists and scientists face a growing number of challenges and questions. what's our goal? 801502000 guerrillas. is it still a wild population, or when does it become a wild? do? oh, the ruthless surviving mountain gorillas live in 2 relatively small areas in the east of africa. one population lives on the slopes of the veranda mountains. a chain of volcanoes straddling the border region between rwanda, uganda, and the democratic republic of congo. the other is located just 30 kilometers to the north in uganda. in the windy, impenetrable forest. a primeval lowland and mountain rain, forest region. 331 square kilometers of land known for its exceptional biodiversity, or home to over $400.00 of the world's last mountain gorillas. the kind of terrain that makes it difficult to determine their exact numbers. there is also a reason it's called impenetrable. now, the vegetation is very done. you can have a guerrilla not very far away from here and not know it because of all of it. martha robins from the max planck institute in germany is on her way to the mo, cheese a group of guerrillas. each class is assign the same name as back into its liter, a silver back, a. after a 90 minute hike, the american anthropologist reaches her destination. we where surgical masks when we're with them. the guerrilla if we're within 10 meters of them, we wear them. because even though right now, i feel very healthy, i'm not exhibiting any signs of having a cold. i may still be carrying it. and the last thing i want to do is get, get these girl effect. so there are several, right you if we just wait, they're going across right across here. this is very rare. that adult female was new jenny, she has the youngest baby who is about 9 months old now. but interestingly, she was also carrying a 2nd infant which is not hers as like an infant. get the phone for extra chemical . there are 13 guerrillas in this group. the silver back is about 20 years old. he has been habituated from birth. i've actually watched him grow up, which is pretty cool. habituate it means that the silver back and his group have been introduced to the presence of humans. the behavioral scientist observes what the animals eat, how they interact, and how the individuals differ. studying every detail of their worlds, although always from a distance where these habituated guerrillas, it's amazing because they kind of led us into their world. so we can observe their day to day activities. it's always very thrilling to see the new babies and to see them grow this ones at the breach the age where he's starting to explore everything and it's, it's really quite fun to watch. and the broader view, though, it's very exciting and good to know that every new baby represents a healthy population and represents that the population is growing. the mountain guerrillas are the only great apes in the world known to be increasing in population. at the end of 2018, the international union for conservation of nature announced the highly encouraging news that they were now classified as merely endangered. in contrast to other gorilla species, which remained critically endangered martha robins has witnessed that recovery in the course of her research. he was born in 1999 and i go out there now and i see him leading a group with 5 adult females. he's got his own kid climbing all over him. i feel so privilege that i've been able to watch the same gorilla over 20 years. every 5 years, the researchers conduct a precise census of the gorilla. it's often an exercise in extreme patience. not all of the groups of blendy guerrillas are easy to track constantly to ensure that every single animal is counted. the team painstakingly comes every section of the rain forest in the process covering several 1000 kilometers on foot. during the census is what we will have 6 teams of 5 people working over a period of about 3 months. i have been involved in 5 not and girl offences. and it is by far the most difficult work i have done here. we see from east twist. so for example, this map, if with one that is so funny, for example, i just said then to move in the neutral. and i know that's what i need. if i was, i went over there over there. but the main thing we're looking for is fresh gorilla trail. so when the girls walk through the far as they're eating phase, they're big animals. so they bass down vegetation, which there was a lot of here. and the trackers experience people were able to see this is a gorilla trail. and if we find that it's great because then we will track to the site and be able to count enough and collect gorillas, make nests every night. so they've been down vegetation and sit in it, and if you have 10 guerrillas in a group, maybe you'll find 8 now. and maybe 2 of those nes, have big adult size theses in it, and then small baby size pieces. and so that's how we can ascertain that there are probably 10 guerrillas in that group, but to ensure that that number is accurate. and it's not a case where one gorilla made a nef and actually didn't like who they were sleeping next to. so they made it someplace else. and we double count that guerrilla. we also do genetic analysis with the theses. we know that this is an endangered population. and the way i look at it is, imagine you're a business man, and imagine you make toothpaste. so again, something very basic, you would want to track how much to space you're making, how much you're selling, and what to do if you're not selling any. so it's kind of the same with conserving endangered species where we need to know how many there are and whether it's increasing or decreasing. because that gives us some indication as to whether the conservation strategies are working or not. or whether we should try something different. ah, just 30 kilometers south in the veronica region. those conservation strategies have already proved fruitful on the horizon, the chain of volcanoes scaling over 3000 meters high that gave the park its name. the mountain gorilla population here has doubled over the last 3 decades. the most recent census covering the border region between uganda, the democratic republic of congo, and were wanda counted 604 animals there were wandered. government has banned poaching and logging in the national park and introduced a controlled tourism concept. part of the resulting revenue is assigned to nature conservation, while 10 percent goes towards the construction of schools, roads, and hospitals and the region. masonic is the gateway to the national park. a city of around 100000, that his florist with the resurgence and tourism a promising example of her wand as rapid development since the genocide of 1994. i'm with her german gorilla expert vinny i caught is a long term associate of the care. so he research center, she's continuing the work of diane fuzzy who set up the facility after coming to her wanda, in 1967 dash i to stand in house on this desk was in diane fuzzies house and had been secured before the conflict in rwanda began she would sit tad practically every evening at her desk with her typewriter and record all the details she'd observed in the groups she'd visited during the day. ask, had observed ations that enabled the pioneering american researcher to start compiling a unique collection of data thought on august. this finance nom, fungal, but it does del, exciting to find name of guerrillas that we've been monitoring since they were really young and watching them grow out of it. it's really impressive. how detailed her observations. well, it's ella thought that hut in the 19 seventy's diane fause, he counted a solitary, $254.00 mountain gorillas, prompting her to embark on an uncompromising fight against poachers and the deforestation of the mountain reinforced. at the same time, however, that commitment was not always welcome and earned her many enemies entitled to us at the time when diana fussy was still alive and protecting the guerrillas out of she didn't believe that they would survive until the year 2000. she assumed that guerrillas would be extinct by then. yup. i don't know which ones and diane fussy did not live to see the turn around me animals for chance. she was murdered in her cabin. in 1985 of her wanton court found her research assistant guilty in absentia. but some experts suggest the true culprit was a poacher. by the years in that down it, what we see here is their habitat, the be silica. i said people the cara simbie volcano, and this is approximately where diane fussy set up her attendance and of both. when vinny, a car to begin her research and were wanda in 2004, there were 3 groups of guerrillas. each shifting trail scene here represents their respective movement patters and these of hawkins. and if i and the aside from, we've seen a tremendous growth in these groups over a period of 15 years, as many as 65 guerrillas in the pablo group, which is an absolute world record the mass. and today in 2004, i wasn't aware that it could be more than one, seal the back in a group. what happened in 2007 took us all by surprise lashawn. a protracted period of stability was followed by chaos. one cause is forced end sensations. equal asthma, 65 guerrillas in one group couldn't work well for long. again, we were waiting for something to happen in the groups, partly split up males dotted to form their own group with some female couple of credits of pablo, for example, split into several groups. and instead of 3 groups before we had at times, 12 groups. so with 3 times as many groups in the same area, hi, martha has less happy tent, the group that it was all and with groups encountering each other. more often, interactions can be incredibly stressful. toughest for the males is camina fight to the death and things can also get critical for the young animals yell from spirit. thought hm vinnie a car tender team of researchers visit the national park several times a week. their mission is to find out how the guerrillas are reacting to their increasingly crowded habitat. the veronica is a small protected area surrounded by a region that is extensively farmed by local residents, with their fields reaching right up to the borders of the park. and the primates cannot simply migrate when conditions become constraint. mm. vinny eckart wants to explore the social dynamics between the primates. she's now on her way to a group named after a former dominant silverback pablo. after living through major upheavals in the past, the group currently number is 24 animals. at the border of the national park, the scientists meet some park rangers. they usually know exactly where the individual groups are at any given time. the team announced their arrival in the guerrillas own language. lucian. yes, i know it's, that's called a belt. well, we'll use it when we arrive and kathy approached the group, but it works like a greeting. we hey, now way coming. it's all good. what is food? if it, you know, you can see the size of the vegetation, vegetable cause the belt vowels are very important so they can hara and soften with them. okay, so those are very special friend. unfortunately a bit too curious. sometimes a flight cook, maybe just take the camera down for a bit in columbus in the day that pablo group are in a peaceful mood. 3 gorilla babies. enjoy frolicking around in the morning. sun completely dependent on their mother's their breast fed until they're about 3 and a half years old. at 9 months, they start nibbling on their 1st plants. and step by step, learn to stand on their own feet in the jungle classroom. ah. but only if an incline i'm where you can see the little one there that's zulu younger than any other he loves to planes as well. sometimes he plays alone. like right now. i thought he was probably unable to find a playmate, but it won't be long until another youngster comes around, which is welcome invitation. will combine idle. ah, ah! at this age fights between the young apes are all about playing. but if the juvenile male wants to challenge the dominant silverback orphan outside, gorilla tries to win the affections of females from the group. things can suddenly take a very aggressive turn. the growing population density over recent years has seen such fights become increasingly frequent. oh, the am for my telephone in 2007, we had about one interaction per month yet. so now we sometimes see up to 3 a day between different groups. so the interaction rate has become extremely high. name woke a gun, babies faced the greatest danger during such fights. as long as the gorilla mother is still nursing, she's not ready to meet again. when a male manages to learn a way a female, he'll almost always kill her young so that he can sire his own offspring with her sooner. infanticide is a phenomenon seen in a range of animals. amanda's life. it allayed for the owner. of course, it's one of those things that are very hard to be witness to and to process. you want to intervene life a little that you know that it's natural behavior that you have to exam and you have to toughen up and not let things get to, you know, unless, but of course it's really difficult. it can be, you've known the young ones and they mothers from day one, and you can see them really suffering and distress it's exert from the whole group . it's hard to accept. that's how it is with a. so this is not the researchers observations have produced some surprising scientific results, whether planning, 15000 kilometers away, tommy or chi yo is a professor of anthropology at the university of california davis, where dian farsi once studied for 2 semesters. the french gorilla researcher updates his students on the latest developments. press visit press. yes, so they do. yeah. they did that. they have, you know, corridors are like most mammals actually they have feelings. a female girl who loses her all spray will be sat for a period of time, but eventually she'd get over a thought she would get pregnant again and hopefully forget a little bit about the tragedy of hubbub. but i do remember distinctly observe a female girl. i remember that i was just lost all spring and she looked sad and she was always sort of on the edge of the group. i'm not very active, not play food for a few months after the death of rosman. no, that meal ca yos focuses on long term data. he uses quantitative methods to monitor patterns and developments covering years or decades and visits the guerrillas in the wild on a regular basis. he benefits from the long term records compiled by the field researchers in rwanda. half a century of observations initiated by diane fussy, have resulted in a massive database that now enables new insights. who was the common cur? pearl isn't because you can clearly see that there were almost no cases of infanticide in rwanda between 198-2000. after that, the number of cases increased dramatically as shown by these little red asterisks here over the last 10 years for the mortality rate of baby gorillas due to infanticide has increased by fold. plus the mortality rate among male gorillas has also risen as a result of wounds they incurred during those encounters. you can use analyses provide the basis for forecasts about the guerrillas future. does the enormous growth in population pose a threat to the animal's healthy development, nani visuals, kinda of pure natural ad? well, the nath we're seeing a level of violence that is no longer naturally us. that's causing a slow down in population growth. and if that level of aggression persistence, it might even start shrinking with poor mamma, the quiet home dice yos and with i guess we'll continue asthma. 2nd, february got mode lather, and in addition to the population, no longer self adjusting stress levels are also on the up. it's a problem we really need to resolve back in her wander, kato's fellow researcher vinny cart is trying to track down the source of that same stress problem mafia. this is our 1st concern was finding out how stressful these interactions can be within a group that you cannot, that sometimes extremely peaceful, especially with groups that would have only recently separated. and it will sometimes be just a playful encounter. but it can also get very, very aggressive thursday because he's applauding from direct observation alone. the scientist cannot gauge the physiological impact that stress can have on individual guerrillas, which is why vinny, a cart is likewise interested in the animal species. yena would papa fun and wipes this is a fico sample from a female that just passed by it in you don't need that much. i used the glove as a conveyor. i'm just turn it inside out. pretty straightforward. the foster on and then tie not. thanks. when i next do you need to write down what time it is of noon? i'll try it. if it's, if it's, if we're in sunfish, it's 1121. i am actually the fecal sample is from move capture do that. so code aloida and, and so the top people in the lab know whose sample it is with us. i filled the note up really small claim and push it into the glove. i agree with this simple i would say to lee more do people not easy to learn more, hold your bob, but to try our best unit of conceive a fire, we affectionately call this apt hoop lab above a 4th order rosen martin doing right now is extracting hormones from the fecal samples we collected in the forest by the summer time as is the case with humans to stress triggers, a hormonal chain reaction and gorillas bodies than i n. a gorilla inches fructose exposure to a stress factor and leads to a very long stress cascade. the fundies are the end product from that reaction of n, incorporated into the feces via the intestines, and then excrete it on done with cash. and that gives us an opportunity to determine the stress level without needing to take a blood sample if alcohol and can be reached capacities and you've advice, beautiful. and here's an example of a very aggressive interaction that took the group completely by surprise as a silver back appeared out of nowhere and ran into the group the front you. and you can see very clearly how the 2 youngest animals had the biggest stress levels on fire because they also at risk of falling victim to infanticide of the fire. and what you can also see very clearly is the stress level going down again after 5 days. good. once this was man's and us reacting to an acute stress factor is vital for survival, lead for humans as well as for guerrillas, for men being ready to fight. that means you can react appropriately to danger muscle, the akin of an agatha. fussy though at this does become problematic. if a stress factor is prolonged or occurs very frequently, and regularly is elf to it. so in a 2nd study, the expert looked into which conditions caused permanent stress and came across to quantifiable triggers is getting of women just there are things we have to keep a close eye on because of changes we've noticed in baseline level on the ve, somebody's been in months when temperatures have risen very high, for example, washington and also mumps with extreme rainfall being defined as this indicates that climate change is a challenge and a hospital with a challenge that's very much being felt in rwanda dry seasons are becoming more protracted, while rainfall is often heavier and more densely concentrated than in previous decades. experts predict a rise in temperature of up to 3 degrees celsius by 2050. yet they are all contempt, i'd guess. just especially cold days would be more likely to cause stress. because you can really see the guerrillas cuddling up together and that they look a bit uncomfortable harry bossy. but it was very surprising that the hot months, some tougher for the gorillas shop that might be connected to them having black fur, which absorbs the sun's rays and can lead to heat stress or through it. but it could also be due to them dehydration quickly. the, the body having to work harder to compensate with malice, it was closed. in addition to climate related changes in the region, a 2nd factor has measurably increased. the animal stress levels done have no escrow . we also found that groups with only very small areas exclusively to themselves. and sometimes none at all showed increased baseline stress levels. not simply because they overlap so much without the group lunchtime. it could damage some, it might be related to them having to share food resources. the fun you don't type, you don't know. the constant possibility of running into another grew a funny one of any cards. research results are alarming. a came to an early warning system as for acute symptoms of stress, that's where the so called the gorilla doctors come in. the vets are called out almost daily due to mountain gorillas, falling ill or being wounded. doctor guest bar ins. eyes anger is one of them then found a way to do things does seem to be tension between the dominance of above and his subordinate. save a few minutes later that vision became into a fight between the 2. we knew that fight it into an injury, which was not really serious. one, it was the one which was to face and bleeding. the 2nd lacking about god's official. and on the on the right. it's not just in the emergency that the guerrilla doctors hit the road. they're also involved in preventative missions, regardless of the weather and how long or difficult be effective today, the team will be making their way up the slopes of the car assembly. it's the highest of the room regents 8 volcanoes stretching to over 4500 meters e, constantly monitoring the head of this foot position. and with the head of our fitted tumult, truck cuts will also report every day on his to death of him who members or sometimes for many hours of high g. because we know where they live in yesterday. and they tried to estimate the distance. but from the morning the as that's also moving out of nowhere, a thunderstorm, a wraps over the rain forest. yeah, yeah, yeah, yeah, thank to get on the scene, you know, after another hour of walking in the constant down port, the vet hears, familiar sounds. good. he's finally found the group the park rangers had already informed him about fights and the wounds to silver back had inflicted on each other. the doctor wants to make his own appraisal with them by the thickened duncan fever, but in that group, he's the one that is of the center that they're challenging it. dominance is a block could either if he has been warned, which is heating in the back. yes, good, good, good. he covered the show goods heating scenes and when it proved for v 11 funding and then how think of being and providing is if i go to this and that's why i keep close eye on this for vision. one into them closer the just a single out rig can rival their position. there's a constant threat of viruses being introduced to the park by visitors. human share 90.4 percent of their dna with mountain guerrillas, making us dangerously close relatives. there was an outbreak in 2009 which here at 2 burritos. and we now managed to find out that to divide us that was responsible for that outbreak was up to the human with the new movers, which is a human fate. us are human efforts to protect gorillas in effect, endangering them a almost to $100.00 tourists a day are allowed to visit the mountain guerrillas in the national park and were wanda with just one hour, with the animals costing a small fortune, a ticket costs $1500.00 us dollars the tourist industry earns the country $17.00 to $18000000.00 a year, and part of that revenue flows back into the parks, conservation and thus direct we benefits the guerrillas. this in britain comes with a challenge to have a broad turn, trim t groups of guerrillas of mountain graders. and what does that mean with her? a hobbit out of 100 to 60 square kilometers. that is very small. together with the park director, the state head of wildlife conservation is looking for compromises that will ensure a satisfactory balance between species protection, tourism, and the growing concerns of the local people. this is the older buffalo that tries to deter roger from coming from the park. we've seen buffers coming, got hoops in good. i was coming, goes nuts not i wish of course, but it's happens as we try to, to better every day. the, the protection of the, the robbers, but also protecting all people. the animals live right next door to the local population. who farm fields with potatoes and beans, as well as eucalyptus reaching right up to the border of the national park. and mountain gorillas have a craving for eucalyptus being accustomed to the presence of humans, the animals feel comfortable roaming around here. francois in the good sir used to be a poacher in the park today here and says living as a farmer, working 7 hectares of land. all with the code of a little run rather though, cuz them walker these fields are mine to ya. knew her from sheer up to the border of the national park with an old us that you manage it look like it. club of the globe, navy, that you, them gluck of that tree. you. if a guerrilla comes and turns off the bark all around it, the inside is all that remains to be loaded up, but it's the bark that carries the soft from bottom to top. so it would, if the box gone, the tree dries out and dies with ethical van. we have to cut it down to your mother, maria tim not only mountain gorillas, but also buffalo and forest elephants. frequently leave the park and destroy harvests, francois and a good sir can applied to the gover for compensation. but it only partially makes up for his losses. don't worry as though they plundered the fields. sometimes they destroy up to 2000 square meters of land, which cost me $5.00 tons of potatoes. instead of earning 1200000 rwandan trunks. i get 122150000 in compensation. while people who live in the vicinity of the national park receive financial support from the government and various organisations, they face losses of 90 percent and you don't go 12. we've often said that the government should put up a fence around the national park that were to end the conflict between farmers and humans. when a conflict that's been going on for decades. since the founding of the national park in 1925 huge sections of land were cleared for settlements and agriculture. as the parks area shrank by 54 percent, the number of mountain guerrillas also plummeted. now that their population has recovered, the government is looking for a different strategy because the pac, it's moe and girl of oppression is drawing. we want to expand it and expanding its men is from this war, seeing and down what about 3 kilometers. there were wandering authorities have already drawn up plans. the park is to be expanded by $3740.00 hector's plus an additional buffer zone covering $6000.00 hector's. the buffers on his buildings best where management is amends under government and the management of a national park. but it was in this buffer than we've been to probably plan to bumble or tea, coffee economy activity that has not hindered the activities of conservation, but sometimes aims to benefit their lockers. the government plans for the parks expansion involve resettling 3600 households with 18000 people in return. it promised them new modern villages with electricity and drinking water or infrastructure that is needed. especially ferguson when health an indication which is key, but also envisioned that one this predict sets about 7500 people the employees regardless of that potential future project. gene dark mucous humana has major worries to deal with in the present. she has a modest piece of land on which she grows vegetables to feed herself and her 5 children. she also works as a day laborer, and in a good month has 25 year olds in her household budget. like many others, she's concerned about not being adequately compensated in mom. i got to learn from my in laws to build a house here. when last is about to take a turn for the worse. well, nobody could call it back and we're going to go to z. i . so the growth in the mountain gorilla population also raises underlying ethical questions with human interests. conflicting with those of wildlife conservation. it's an issue that also concerns scientist, martha robbins and uganda. germany's max planck institute for evolutionary anthropology has an outpost in the pointy forest. this is what i call the gorilla. well, it's vaguely an art me check. so this is something i just kind of started for fun to mark the development of individual guerrillas. so each column is a different individual gorilla. these 2 infants were born about 2 years ago. this one about a year and a half ago among wendy gorilla females typically give birth every 5 years. the biologist has discovered though, that in the virginia region, the time between birth is a year longer. this means that the population, wendy, is not growing quite as quickly. but overall the trend is positive. they represent more than the numbers. i mean, we know the population of increased, but at the same time it's made up of individuals. we have only about a 1000. so on the one hand, we still run the risk that they could go extinct. but on the other hand, we need to shift and start thinking differently about some management strategies. a to the max tank instituted for anthropology in lab, 6 germany 90 percent of the mountain gorillas from wanda, uganda and the congo are registered at the genetics laboratory here. the result of the scientists extensive census work and the statistics confirm their growing numbers. the most recent census and the blendy forest counted $459.00 mountain gorillas together with their counterparts in the virginia area. the total figure is $1063.00. i think the success is a success, but the question is, is it too much of a good thing? you leave her unblocked caroline. you were this past when you were the ma 30. they don't. if a professional the of go, it's very likely that the stress level and death rate at the gorilla population will increase. more animals will have health problems or die than has previously been the case there. and you can ask yourself, will local authorities and international organizations allow this and accept the fate of this population viagra said with saw the said book su west journal, about his dad's investment often or will they be tempted to intervene? that we have more people in the national park protecting guerrillas haggle than guerrillas themselves. he bought more researchers, conservationists and tourists than anywhere else in the world. today, the gorillas depend on human life, liberal and humans depend on the guerrillas. we no longer really have a species that lives while to untouched as an independent of human activities activity. mm hm. ah, how much intervention do we want to do when we're monitoring them? if the management goes very, very far in terms of what kind of medical care these guerrillas are getting, are we supplementing a diet and we are so far away from that now. but is it still a while population or when does it become a while? do this is a conversation that need all the people involved in guerrilla conservation, and that conversation needs to start now. ah, targeted killings by combat. drones are being prepared at the u. s. military base, and lunchtime the problem the base is on german soil. does german law permit drone attacks? what does the u. s. systematically abuse german law? death by drone, close up in 30 minute. d, w. to own or not to own. what about a sharing economy instead? a change in thinking is changing the economy to create something new. the economics magazine made in germany even 90 minutes on d w. and he had a special hotspots in germany, europe and the world dw travel truly were in a been learned german with this award winning offer is available worldwide. and for every language level, learning german has never been simpler. german to go ah ah, ah, this is d, w. news live from berlin. the bloody battle for buck moved intensifies even further rushes. what wagner's group claims that it now 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