Habits and Lifestyle
Southern pig-tailed macaques are mainly terrestrial, but also skilled climbers and often forage in the tree canopy. Unlike almost all primates, these macaques love water. They live in large groups that split into smaller groups during the daytime when they are foraging. There is a hierarchy among males, based on strength, and among females, based on heredity. Thus, the daughter of the alpha female will immediately be placed above all other females in the group.
The alpha female leads the group, while the male role is more to manage conflict within the group and to defend it. Pig-tailed macaques are generally silent but they make a lot of vocalizations when they need to. They communicate with each other with the help of screams, squeals, growls, barks, screeches, and have the most common vocalization the sounds as ‘coo’. Group members also groom each other, kiss, and feed together.
AVAILABLE PIG-TAILED MONKEYS
A proactive forest department, supportive local communities, and the constant presence of researchers has helped the pig-tailed macaque’s conservation in the forests of Hollongapar
Walking through a pebbled path in the earliest hours of a dewy morning, a fog still clings to the forest canopy. Morning calls of gibbons stir the silence of the forest. They signal to us that the inhabitants of Hollongapar Gibbon Sanctuary are waking up. We walk along the straight forest path and take a turn onto a forest trail, intending to venture deeper into the jungle.
Suddenly, we hear a sound close to our right, a soft rustle of leaves. A small monkey stares down at us from the nearby tree. Fur frames its face. Its face is coloured a pale pink, its dainty fingers grip the branch of the tree. We can almost swear it stole someone’s eyeliner and skilfully applied it to its eyes. Entranced by the monkey, we step towards it and the spell is broken. It retreats into the jungle. We realise that we were greeted by a baby pig-tailed macaque, in a forest in the heart of Jorhat district, Assam.
Shy and furtive, northern pig-tailed macaques (Macaca leonina) are predominantly arboreal and diurnal. Groups of pig-tailed macaques are composed of multiple males with their female cohorts and offspring. Their infants and young ones always stay in close vicinity of their mothers or adult female members. A group will frequently break into smaller sub-groups and forage separately. However, they keep in touch with each other through soft ‘coo-coo’ calls, as visual contact is severely disrupted by the dense foliage. These dense rainforest monkeys fare better in undisturbed forests and will rarely venture out to forage.
Pig-tailed macaques are predominantly frugivorous i.e. their diet is composed of fruits, however, they also extensively feed on insects. They love to forage for insects in the foliage of Vatica lanceafolia, a Critically Endangered dipterocarp tree species, found in healthy density in Hollongapar. Vatica, along with other medium-sized tree species, form the mid-canopy that is very crucial for the movement of pig-tailed macaques and other canopy-dwelling species of Hollongapar. However, due to unsustainable harvest of Vatica, which is the most preferred fuelwood tree for locals, the mid-canopy is severely broken.
Over the past 30 years, the pig-tailed macaque has become extinct in several forest fragments of the Upper Brahmaputra Valley of Assam. However, its population is thriving in Hollongapar despite its habitable forest area having been reduced to just 17.71 sq. km. A major threat to pig-tailed macaques is habitat loss. Our study found that the occurrence of pig-tailed macaques is positively correlated with the area of forest fragments. However, the fragments of Upper Assam have lost one-third of their area due to expansion of agriculture, tea plantations, and human habitation. Many of them have been reduced to faint shadows of their past.
Though they have disappeared from other forests, pig-tailed macaques have increased in numbers in Hollongapar. At present, four groups of pig-tailed macaques reside in Hollongapar, with around 20-25 individuals per group. A possible reason for this increase may be due to non-overlapping of their diet with the stump-tailed macaque, which mostly forages on the ground. Both species avoid each other when they are in close vicinity. Pig-tailed macaques, however, sometimes compete with hoolock gibbons for food and trees to sleep in. We also suspect that the disappearance of Assamese macaques from Hollongapar may have benefitted pig-tailed as both might have shared a similar niche.
Hunting of pig-tailed macaques used to be a major practice in the past and still is in some parts of Northeast India. Their meat is consumed, and the bones are used in traditional medicine. Some macaques are even kept as house pets. In Thailand, pig-tailed macaques are used to harvest coconuts. Pig-tailed macaques are elusive creatures; they hide from humans, particularly in areas where they are or were frequently hunted.
Fortunately, that is not the case in Hollongapar, possibly due to a proactive forest department and the fact that the local communities surrounding the sanctuary do not hunt them. One possible factor that may have contributed to the sanctuary’s protection is the constant presence of researchers determined to protect the sanctuary and ever willing to report any illegal activities they detect.