GEORGE TOWN, Sept 12 — The skies brightened as dawn broke, but all was quiet in a residential neighbourhood in Tanjung Bungah except for the hushed rustling of leaves as a group of dusky langurs stirred from their slumber on the canopy of a tall rainforest tree.

Ah Tan, the alpha of the group, shook off the rainwater and surveyed the skies to ascertain if the rain had stopped.

His family, sleeping on branches near him, also shook themselves dry and started moving around, leaping to nearby branches to break off shoots and leaves for breakfast.

Underneath the tree, a small group of citizen scientists, armed with binoculars, stood quietly and observed Ah Tan and his family of seven.

One trained the binoculars on the dusky langurs and noted their individual movements — female, male, infant, walking, leaping, feeding or sitting — while another entered the observations into their research database.

Langur Project Penang (LPP) founder Yap Jo Leen said citizen scientists collect data on the activities and behaviours of the dusky langurs every 15 minutes until the end of the sampling period, usually lasting about five to six hours each.

“Field work is a way for them to observe the langurs and after a while, some of the citizen scientists will have learnt to identify each individual langur,” she said.

Ah Tan’s family, also known as the Concord group due to their location near the Jalan Concord area, travels together to forage for food, which is mostly made up of young leaves, shoots and unripe fruits.

Yap said the dusky langurs needed to consume a diet rich in cellulose mainly from leaves, seeds, shoots, flowers and unripe fruits so they have to move around to look for vegetation that suits their needs.

“They don’t eat just any leaf. They are selective on the types of leaves, the types of trees and the types of fruits, which is why they move around throughout the day to search for a particular tree or plant,” she said.

Ah Tan’s family travels around their home site that spreads out about 13 hectares, across quiet residential areas and connected by trees, electric cables and Numi’s Crossing, a special bridge built by LPP as a crossing for the primates and other wildlife.

As soon as the rain stopped, Ah Tan honked as a signal to his family that it is time to move and soon, started leaping to the branches of another tree.

The group followed, one after another while the youngest, Sunny, clung to her mother, Kim.

Each of Ah Tan’s family was given a name by LPP members, Ah Tan in honour of a citizen scientist who is also a resident in the area, the two older females, Kim and Andrea, a young adult female, Julie, a young adult male, Luan Luan, and two female infants that are fast becoming juveniles, Bumi and Sunny.

Julie, Luan Luan, Bumi and Sunny are Ah Tan’s offspring with Kim and Andrea.

After recording and tracking their movements in the area for years, Yap and LPP project executive Wong Hui Yi could easily identify each individual.

“Citizen scientists will also learn to identify each individual over time,” Yap said.

She said the data collected by the volunteer citizen scientists were often collated and tabulated to produce reports and presentations for educational campaigns.

“We are collecting data mostly for advocacy and educational purposes, not for scientific research, so citizen scientists can choose to conduct monitoring once or twice a week depending on their time availability since many are working or at school on weekdays,” she said.

She said citizen scientists are advised to conduct monitoring sessions in groups with a minimum of two people for their safety and not in too large a group.

She said the group has to be kept small so that it does not cause disturbances or agitate the dusky langurs.

Meanwhile, Ah Tan and his family have moved onto the rooftops of houses in the absence of tall trees, carefully selecting houses that are either vacant or the ones with fruit trees or plants that offer them sustenance.

Yap said the dusky langurs are intelligent primates as they know to avoid houses of people who didn’t like them and had shooed them off previously.

The family stopped to feast on unripe jambu air (rose apple) from a tree in front of one of the houses before moving on, each time with Ah Tan patiently waiting for every member to finish eating before he moved.

Each time they found a tree to forage, they would spend between 30 minutes to over an hour leaping between branches to feast on young leaves, shoots and flowers.

The dusky langurs moved quietly and Ah Tan only issues a honk once in a while, sometimes as a warning, sometimes as a call for his family to move.

Ah Tan, once he finished eating, would stand guard at the highest point, watching out for intruders, predators and danger, such as other groups of dusky langurs or macaques.

“Sometimes, if there are enough resources, the dusky langurs can share a site with the macaques, but if there are not enough resources, they do not get along,” Yap said.

Even between different groups of dusky langurs, there is a possibility of conflict if resources are limited.

Although the neighbourhood that Ah Tan and his family call home boasts of streets lined with trees and fruit trees planted by residents, the resources may not be enough for a larger group.

Wong said the primates naturally control their group size according to the resources available so Ah Tan’s family had remained relatively small.

She added that other groups with 20 members and some groups have more members, especially when their home site has more natural resources to feed all of them.

The dusky langurs often move around their home site, going from tree to tree, using different routes each day according to the whims of the alpha.

Yap said Ah Tan’s family has between four to five different routes that they will use on different days.

“Ah Tan will decide on a route and the family will follow; sometimes, if there is danger in that route, he would change direction,” she said.

By mid-morning, the dusky langurs will probably take a brief nap before continuing on their journey to forage on other trees in their home site.

It’s not just about foraging for the dusky langurs as according to Wong, they will also have social and play time in the late afternoons.

Just like the schedule of a human’s workday that ends by the evening, the dusky langurs usually end their foraging the moment it gets dark, around 6.30pm.

They do not have any specific tree that they will go back to sleep at night, but Yap said they have several trees that they preferred, especially tall trees with young leaves they can eat upon waking.

LPP is now accepting applications from students and the public who wish to be a citizen scientist to learn more about the dusky langurs.

“We want to reach out to more people, get more youths to join and to spread awareness as part of our advocacy in spreading more understanding about the dusky langurs,” Yap said.

For more details, go to https://langurprojectpenang.com.