Meet Jihosuo Biswas
Primate Conservation Limelight
Dr. Jihosuo Biswas
Dr. Jihosuo Biswas is a renowned wildlife researcher with over 25 years of experience, specializing in the study of primates in Northeast India. He holds a PhD from Gauhati University (India) and possesses additional certifications, including one in Endangered Species Management from the Durrell International Training Center (Jersey).
Throughout his career, Dr. Biswas has conducted extensive field research and published his findings in over 37 scientific papers. These papers have focused primarily on primate species including Arunachal macaques and Bengal slow lorises, but his most significant subjects are western hoolock gibbons and golden langurs. Since 2002, Dr. Biswas has served as the Coordinator at the Primate Research Centre North East India, where he effectively applies his expertise in biodiversity, environmental policy, and natural resource management.
In February 2023, NEPC had the unique pleasure of interviewing Dr. Biswas (via video call) while he was working on the design and implementation of canopy bridges to help golden langurs navigate the fragmented forests of Assam, India.
Primate conservation is very important, particularly in this era of climate change. Not only because they are charismatic, or very close to us mythologically, but they’re also our close relatives. They came first. So, they’re like our elder brothers and we have to treat them like that.
I’m in the Chakrashila Wildlife Sanctuary. It is a sanctuary declared for the protection of the golden langur as a flagship species.
We are in the process of putting some artificial canopy bridges over roads in order to minimize traffic accidents involving the endangered Gee’s golden langur, which is endemic to the Indo-Bhutan border. Roads and electric wires fragment the forests where the langurs live, and langurs are frequently being electrocuted or hit by cars. Once they’re up, the langurs will be able to use these artificial bridges instead of the ground to cross the gaps in the canopy. The bridges will also help them to access resources within their home range without having to venture to the ground.
Actually, only a few hours ago one adult female and one infant langur were hit by a car. The female died. The infant is still alive and has been rescued. The day before yesterday, another female was hit by a car, which shows how important these bridges are for the protection of this species.
We just started this project. So, we have developed some designs, but there are a lot of technical aspects to consider. Golden langurs are listed as a Schedule I species in Indian Wildlife Protection Act of 1972.
Schedule I are the most protected species in India—up there with tigers and elephants. So, there are many formalities we have to consider with how these bridges are constructed, and where… and we need to get a lot of permissions. Whenever you manipulate the habitat like this, you need to get approval from the government.
So, we have to acquire many permits for all these things, which requires some time. But since yesterday, we have started, you know… actual fieldwork.
Unfortunately, today we have had to deal with situations with these langurs being hit by cars. Yesterday, in Chakrashila Wildlife Sanctuary and today in another proposed wildlife sanctuary nearby, Kakoijana, a proposed Wildlife Sanctuary.
That last one happened around 1 pm. Now it’s 3 pm.
We are working under an organization called Primate Research Center—Northeast India. I am the coordinator. I oversee the projects and, as a primatologist, I am planning, writing and raising funds for the projects, networking, making designs, and executing the projects.
First, we put all the effort into monitoring the langurs. I supervise all the aspects of that work. Taking down the data, for instance for corridor inventories, identifying potential sites for corridor restoration to link fragmented populations through village matrices. Then we are identifying those areas where the langurs need canopy bridges and where natural connectivity is infeasible over linear infrastructure. In the next phase, I’ll oversee construction of the bridges and also help prepare the sites for data collection. We’ll put some camera traps high up in the canopy so that we can know with what frequency the langurs are using the bridges, as well as with what rate of success the bridges actually help them cross.
As the coordinator, I have to pay careful attention to all these things because if mistakes were to happen, langurs may die. Fortunately, the golden langur was the subject of my PhD. I’ve spent more than 25 years dealing with this species, and I also know the area well. So, I know what I’m doing.
At the same time, I start preparing local communities. We train community volunteers as “Sugriv Sena,” the monkey warriors. We actually empower local community groups by giving them the skills and knowledge that golden langur monitoring requires, as well as management so that they can play a stewardship role in conservation. Then, we can ask for their help during our research.
We also do a lot of educational programs to sensitize fringe community members about the natural world of golden langur through different audio-visual aids and through different participatory activities like dramas, role play, games, etc.
We are training community leaders and local teachers as well through our Educator Training program on golden langur conservation education. It is in the line of “train the trainer” programming with a goal to make every teacher a conservationist and every community leader an educator so that they can help us educate their communities about these topics.
During 2020–21, we finished a nationwide population estimation survey of golden langurs under my leadership. The results are encouraging. This is the third systematic survey that we have done. One we did in 1996–97. The second one was in 2008 and 2009. Both under my leadership as well. We just finished the third, and now we are communicating with journals to publish our data. So, part of the job is also preparing these sorts of things.
We estimate that at least 7,400 individuals are living in the Indian part of their distribution range and the population trend is increasing. Based on this data, we recently organized a “Strategy Planning Workshop to Develop a Conservation Action Plan for Golden Langurs in India” involving multiple stakeholders. Now my team and I are drafting an Action Plan for the species, which will be coming out shortly. My current activities with canopy bridge installation are the outcome of one of the recommendations of this very workshop.
Our population survey also indicates that about 25% of the population in India lives in 12 different fragmented forests of its southern range. So, we are planning to restore a few corridors to connect these fragmented populations of golden langur in order to support regular population exchange and ensure continuous gene flow. Due to human settlements and agricultural expansions, regular population exchange has been cut off. But langurs often use villages for refuge and snack on plantations’ crops. So, we are reaching out to these local communities in hopes that they will help us plant trees in peoples’ backyards that the golden langurs can use for food or shelter this upcoming monsoon season. We hope this will eventually promote agroforestry and eco-restoration in and around these villages.
I have already had a meeting with the Deputy Commissioner of Kokrajhar District regarding electrocution of golden langurs on the live electric wire within the villages there. She has instructed the electric department to insulate the live wires to minimize these sorts of deaths.
Yes, in India there has been improvement, but not in Bhutan. Back in 2003, the Bhutan population was estimated to be around 6,500. But in the most recent survey, conducted in 2017 and published in 2019, they only estimate about 2,516. That means there has been more than a 60% drop. That’s Bhutan. In India, there’s been an increase.
No, no, no… it actually has to do with how the researchers in Bhutan got their estimates. In 2003, and then in 2005, they only surveyed a very small area. Whatever density they got, they multiplied it, extrapolating that data for the entire range. So, that’s why the numbers they pulled in 2003 are so much greater. This 2017 survey is the first systematic survey [which didn’t extrapolate the data in this way] ever done by the Bhutan government.
Fortunately, yes. Because in both India and Bhutan they are not hunted. This is true in the Indian part of their range, especially. The golden langur is represented in the great epic, The Ramayana, as the monkey king, Sugriva. So, the people already have some attachment to the langurs.
In 2021, the provincial government upgraded one forest reserve, the Ripu Reserved Forest—a major area of 422 sq. km (163 sq. mi.)—to a national park, the Raimona National Park. Before 2016, only 20 to 25% of the forest where golden langurs lived in India was protected. Today, almost 70% of their range is under protection.
Tigers, elephants, rhinoceros—they get a lot more priority than the monkeys in India. But now, fortunately, in 2021, two national parks were created. One is for golden langurs, the Raimona National Park, as a flagship species, and another is for the western hoolock gibbon, the Dehing Patkai National Park. Both these national parks were founded with primates as their primary flagship species. So, that’s good! The government has also proposed to upgrade Kakoijana Forest Reserve, another small but potential golden langur habitat, to a Wildlife Sanctuary. And soon Raimona National Park will be extended by annexing the Chirrang Forest Reserve.
Golden langurs, hoolock gibbons, capped langurs, Bengal slow loris, and a few different macaques: Arunachal macaques, Assamese macaques, white-cheeked macaques, stump-tailed macaques, pigtail macaques, and some others.
Golden langurs, gibbons, and the sinica group of macaques are my specialties.*
[*The sinica group of macaques includes toque macaques, Macaca sinica, bonnet macaques, M. radiata, Tibetan macaques, M. thibetana, Assam macaques, M. assamensis, and possibly stump-tailed macaques, M. arctoides.]
In one of our publications, my colleagues and I first reported the eastern hoolock gibbon in India. I think that was in 2005. More recently we published two papers on gibbon genetics where we confirm that it was not eastern hoolock gibbons we identified after all, but the western hoolock. Turns out there are no eastern hoolock gibbons in India, only western hoolocks with three distinct populations.
The Mishmi Hill population of gibbons is trapped between two major river systems, the Diban and Lohit. Morphologically, they look different. So, there are other researchers who say they represent another subspecies of western hoolock gibbon. Still, as for our genetic study, we describe three major populations of western hoolock gibbons in India. One population is found in southern Assam, another at the center of Assam, and the third one is the one we looked at in our study.
Our seven-year-long study on a community-conserved village population of hoolock gibbons in Upper Assam, which was published recently in a book chapter under Cambridge University Press, brings some interesting insight into their social behavior. We reported female surrogacy, flexibility in pair bonds in both males and females, male replacement and tenureship, and male/female dispersal for the first time in the species in India.
Another population study we conducted on hoolock gibbons in the Karbi Anglong District of Assam indicated that the district comprised 65% of Assam’s hoolock gibbon population. It is worth mentioning that the state of Assam contains about 70% of the population of western hoolock gibbons in India.
In my childhood, I saw a lot of rhesus macaques. They are quite common where I grew up. But other than that, the first primate I saw in the wild was the western hoolock gibbon. When I was a master’s student, I attended a training program organized by the Indo-US Primate Project.
A big project on primates was launched at that time under the auspices of the US Fish & Wildlife Services and the Indian government’s Ministry of Environment and Forests. We were taken to a wildlife sanctuary called Bherjan-Borajan-Padumoni Wildlife Sanctuary. There were six different species of primates. This was where I first saw gibbons. At that time, they were very easy to see in this particular sanctuary due to their small home range, but now only one family is left in that particular wildlife sanctuary because of canopy cover loss and habitat destruction.
It affected me a lot because, during my master’s, my specialization was in entomology—insects. But after seeing gibbons, I was so excited that I thought: “Well, okay—I’ll do my master’s dissertation on gibbons.”
In Guwahati, the headquarters of the capital of Assam, there is a small river island called Umananda. It’s one of the smallest inhabited islands in the world. At the time, two hoolock gibbons had been released there by the Forest Department. After coming back from this field training, I thought: “I’ll do my master’s dissertation on these hoolock gibbons.”
But when I got to the island, I found that the gibbons had died, and instead, there were golden langurs living there. This island has some interesting history. An ancient Shiva temple is located there. A Hindu temple. One Hindu priest also built a Hanuman temple on the island recently.*
[*Shiva and Hanuman are both deities in Hinduism. Hanuman is often depicted as a monkey, more specifically a langur.]
He built the Hanuman temple and then brought one male and one female golden langur from Chakrashilla, mistaking them for Hanuman langurs. This is not the natural distribution range of golden langurs, of course. Golden langurs are found on the north bank of the river and hoolock gibbon on the south bank. So, these species don’t normally interact with each other in the wild.
After the golden langurs were released, the two species—the gibbons and the golden langurs—fought each other, since they exploited the same niche, the same canopy, eating the same food. Ultimately the female gibbon died during a fight. And the male was so scared on his own that one day he just drowned in the river.
When I arrived, in 1996, I initially thought that the gibbons would be there. But actually, only the golden langurs were. So, then golden langurs became my second love. My first love is the gibbons.
I started my master’s dissertation there. Then I continued with my Ph.D. Basically, my master’s is in entomology, but I purposefully changed course because primatology is my true love.
I want to encourage people, particularly local people, but also university students, to take part in conservation. Because we need more people. My colleagues and I are getting old, and we need people with new energy and who bring a lot of new ideas, to get involved. It’s a very meaningful challenge.
I want to encourage people, particularly local people, but also university students, to take part in conservation. Because we need more people. My colleagues and I are getting old, and we need people with new energy and who bring a lot of new ideas, to get involved. It’s a very meaningful challenge.
Earlier, our priority was to conserve the forest areas. But now there are a lot of new challenges because, in India, the human population is increasing day by day. And the resources are growing very limited. So, there is conflict between humans and other animals, particularly for land.
Primates require forested land. And as the human population increases, they’re encroaching more and more on these areas, clearing the forests. So, for example, golden langurs are left with mostly fragmented forests, and their populations are isolated. Trapped! Golden langurs, gibbons—because they are purely arboreal—cannot travel effectively on the ground. Then, in these tiny forests—say 10 square kilometers, 20 square kilometers (3.9/7.7 square miles)—only few individuals are left, and you get a bottleneck; there are more females than males.
So, ultimately the challenges are meaningful. We’ve gone from conserving the area—protecting it—to having to figure out how to safely manipulate the environment if we want to maintain the diversity of these populations. There’s been a paradigm shift.
Meta-population management. Genetic studies. These are some of the new challenges that are up-and-coming. At the same time, we are also doing some health hazard studies since these primates are so close to human beings. So, there are a lot of diseases that are not reported, and that are not studied as well. Because they are so close to humans, primates are a major potential vector for new diseases. After this COVID era, I think you can understand, it can be very significant if they become the vectors for new diseases.
So, we must encourage the younger generation to come with new ideas, more gadgets, more technology, and push conservation further forward for the sake of these animals.
If you’re talking about the whole pan-Indian scenario, the primates’ conditions are very poor. Because, you see, more resources and funding are given to one particular species: the tiger. Second, is the snow leopard. These are the animals generally considered the most charismatic. Next elephant, rhinos, et cetera. So, there’s very poor funding for other animals. The Forest Department has huge resources, and they are the custodian. They’re the custodian of the forest, and we are helping them. We [conservationists] can provide suggestions. But ultimately they have to do the management.
Particularly in central India, there are no charismatic primates. Macaques are everywhere, of course, but these are generally not considered “charismatic” by the people living around them. Only in southern India do you have the lion-tailed macaque. It’s considered a very charismatic species, not to mention it’s endangered. Then you have the slender loris, or the Nilgiri langurs—they’re endemic to their habitats.
But other than that, there are bonnet macaques, rhesus macaques, Hanuman langurs—they’re everywhere! So, they get much less priority. They are essentially, and unfortunately, neglected. But since we have some charismatic, as well as endemic, species like gibbons or golden langurs, they’ve gained some importance day by day. For instance, after a 20 year battle, the government was finally persuaded to found these two new national parks that have gibbons and golden langurs as their flagship species. This is good for all primates, not to mention all wildlife living in or adjacent to these areas.
Primate conservation is very important, particularly in this era of climate change. Not only because they are charismatic, or very close to us mythologically, but they’re also our close relatives. They came first. So, they’re like our elder brothers and we have to treat them like that.
In forest ecology, they play a very vital role because they’re the seed predators and seed dispersers. Sometimes they may even play the role of pollinators. And, they have some poly-specific associations with other animals. Because, as arboreal animals, whatever they eat, they often drop and those dropped items are eaten by ungulates and other terrestrial animals.
[These scraps] are eaten by other species, like deer, which cannot climb trees. So, they help the forest ecosystem remain dynamic, and that is a very vital role they play. They maintain the diversity of the forest ecosystem because whatever they eat, they swallow. And when they drop it in the feces far away, they act as planters.
They also act as pollinators because while they’re eating flowers, they help pollinate trees. So, there are many ways that they’re helping. They’re very, very important—particularly the forest primates.
In Assam in particular, there is a lot of hope. The new national parks, for one. Day by day, we are still pushing the government to create even more protected areas, because we’re targeting these primates as flagship species since they are the arboreal ones. When you target arboreal species like golden langur or gibbons, you ultimately protect these woodland habitats.
Because tigers and elephants mostly reside in grassland. For woodland habitats, if we target these arboreal species, the entire ecosystem has to be protected. And since they’re very close to human beings, particularly in Hinduism and other religions, it’s easy to convince people of their importance.
And when it comes to golden langurs and gibbons, there is much less conflict with human beings. People love them. There are even certain places where gibbons stay in the village areas for 30 or 40 years and they are surviving. There is no conflict.
So, that makes it easy to spread the message about the importance of primate conservation since so many are already open-minded about it.