On the 11th May I woke up at 3:50am, got myself ready and met Supian, my boss on the red langur project, at the start of Transect 0 where wooden boards take you deep into the forest. The previous day we had found Group BD and followed them until they chose a tree in which to spend the night, which was where we were now headed.
The sleeping tree was only about 800m into the forest so we got there quickly even in the dark. By 4:45 we were sitting quietly beneath the tree listening for sounds of the red langurs waking up. By the time it was starting to get light – at about 5:30 – all eight members of BD had jumped from the tree and were moving south, with us in close pursuit.
This day I was taking behavioural data on Kris, an adult female of the group, and her dependant baby, while Supian took GPS and feeding data. Kris is the oldest member of the group and her son, at nearly six months, is the youngest. When I arrived at Sabangau in January his fur was completely white; now he only has a few patches of white fur left, replaced by the red of the adult langurs.
The group headed West, moving into the centre of their home range. Unfortunately for them this area is shared by the gibbon Group C, and at about 6:20 we found ourselves surrounded by gibbons. Chilli – the adolescent gibbon in Group C – loves to chase the langurs and spent about twenty minutes tormenting members of the group, waiting until they settled in a tree before swinging in close and causing them to scatter. For all the time the gibbons were with us we could not see Kris, and it was only once they had lost interest and moved away that we spotted her and her baby hiding out in the low branches of a tree, safely hidden from the bullying gibbons.
In the next few hours the group continued West, jumping from tree to tree as they searched for food. With the start of the dry season there is less fruit in the forest than in the last few months, so their choices of food were limited and they fed mainly on Liana Willugbeia and various species of leaf shoots. In the dry weather there is also less water in the canopy so a few times we witnessed the langurs coming down to the ground to drink out of puddles.
Red langurs tend to have a long rest in the middle of the day, which is nice for us researchers because we get a rest too! Today was no exception, and the group rested between 9:35 and 11:25, giving me and Supian a chance to set up our day hammocks and eat our lunches without the worry that our focal would move and we’d lose her. It was very relaxing up until Kris woke up and decided to have a pee – right above where we were sitting!
Pretty soon we were on the move again, the langurs travelling quickly now through the lower branches of the trees and stopping to feed less often. At one point Kris moved so fast that she left her baby behind and he cried out for her to come back and collect him. The sky was getting darker and darker and at 15:15 the first drops of rain started to fall, before turning into a downpour which made it hard for us to look upwards into the trees, let alone spot Kris amongst the swaying branches.
When the storm had passed forty-five wet minutes later, we were able to see a bedraggled-looking Kris moving quickly towards a tall Meranti tree – the sleeping tree! She climbed the tree and by 16:20 we were able to call it a night and head back to camp, marking the route to the tree with cotton thread so that we would be able to find it again the next morning. The data we collected will be entered into the database and form part of our research into the behavioural, feeding and ranging habits of red langurs. It’s exciting to be involved in the first stage of this process and to get to see how the langurs’ daily activities change over a period of weeks and months.