Capped langurs (Trachypithecus plieatus) are found in a narrow geography: Assam and eastwards to Myanmar, and northwards to Bhutan and a small part of Tibet. In Manas NP we mostly saw them in upper branches of trees, munching on leaves. Their diet is mostly leaves, with a little variety provided by seasonal flowers and fruits. Once I saw two bands tried to claim the same tree. After some hissing and chattering one group gave way. Unfortunately, I was taking a video of something else while this conflict was on. There are multiple subspecies, but north of the Brahmaputra and west of Jia Bhoroloi, where we were, is the domain of Trachypithecus pileatus tenebricus. A description of tenebricus that I read was very accurate for the individuals we saw: “hairs radiating from the forehead to form a shaggy cap.”
They looked really confident in the trees, where they spend most of their time foraging. As our jeep moved along a path in the jungle, I saw a band of about ten jump from the canopy on one side of the path to the other. The forest department makes sure that the paths are narrow enough for the monkeys to cross. Although this is one of the commonest monkeys in this region, their numbers have fallen enough that they are already classed as vulnerable. You don’t want to cut up a population into even smaller pieces by putting uncrossable barriers in their way.
I took this photo after the conflict between two bands that I mentioned earlier. The mother and young are alert to danger. The young take about half a year to begin to let go of mamma’s apron strings. I guessed that the little one here was younger than that. It would have gestated for 200 days or so, and, was likely conceived the previous May, at the end of a short mating season which lasts through April and May. There is another mating season which lasts from September to January, but a child conceived in those months would have not been clinging to the mother so closely. Females take care of absent mothers’ young, which perhaps explains the lack of annual pregnancies. You can learn a lot about a pack by just sitting and staring at them.
Science da kamaal! Posts appear automatically while I travel off net.
The bare facts: capped langurs were found only in north-east India, Bangladesh, Bhutan, north-west Myanmar and, possibly, south-west China. In India they are extinct in Nagaland, Mizoram, central and eastern Arunachal Pradesh, and Meghalaya due to hunting and habitat loss. In Assam their population is now about 20,000, half of what it was in the 1980s. Most of what are left are in small and fragmented populations, which are quite possibly headed for extinction. Some Indian naturalists feel that IUCN’s classification of this species as vulnerable is too optimistic. If all this is true, and I have no reason to doubt it, then you and your children may be the last to be able to see Trachypithecus pilateus.
Our car was on its way to Hoolongapar sanctuary, when someone spotted the langurs. We tumbled out to look at the troop busy eating leaves and fruits high above us. In this place they payed us little heed, experience has taught them that humans are not enemies in this area. I noticed dark fur on the back shading to a lighter colour in front (see the featured photo). The golden tinge in the chest and belly hair (photo below) was much more pronounced in some individuals. The Family said “They look like golden langurs.” The cap of stiff bristles around their face was clear, and can be seen easily in the photo of the monkey jumping between trees, which you see above. It was a very brief encounter. Later I realized that we must have seen the subspecies called Trachypithecus pilateus pilateus, which populates the area south of the Brahmaputra. The subspecies T. p. brahma and T. p. tenebricus are found north of the river, and are separated from each other by the river called Jia Bhoroli or Kameng. I resolved to make a trip to see those.
Our encounter was brief, partly because everyone in the car was in a rush to see gibbons, but also because the langurs were not doing anything interesting beyond sitting and eating. Apparently they spend most of the day doing this, moving slowly through the forest. Gibbons, capped langurs, and other species of monkeys share these ancient rain forests and seldom interact with each other (although interesting stories about their few interactions can be found here), presumably because they are specialized eaters. The capped langurs seemed to be feeding mainly on leaves.
We got back in our cars and moved away, only to realize much later that the sight we had seen was going to become rarer and rarer over the coming years unless something is done to stabilize the population of these vanishing monkeys.