The bearded pig (Sus barbatus) is the largest wild mammal you are likely to encounter on the trails of Bako National Park. Adults can weigh over 100 kg, and the males grow a distinctive white beard of long whisker-like hair from the muzzle — hence the name. They are surprisingly common and surprisingly unafraid of humans; a solo boar rooting through leaf litter on the Lintang Trail will often simply glance up and continue foraging rather than bolt into the undergrowth.
Bearded pigs are mast-event specialists. When Borneo's dipterocarps synchronise a mass fruiting event — which happens erratically, sometimes only every 7–10 years — pigs travel enormous distances to exploit the windfall of fallen seeds. During normal years they subsist on roots, fungi, invertebrates, carrion, and whatever fruits have fallen. At Bako, they are permanent residents rather than seasonal migrants, sustained by the park's year-round productivity.
Watch for their rooting sign: patches of turned-over soil and leaf litter where a pig has been digging for tubers and invertebrates. This disturbance is ecologically important — it aerates the soil, accelerates decomposition, and opens small light gaps that allow seedlings to establish. Bearded pigs are also one of the few species that follow proboscis monkeys and macaques through the canopy, waiting below to eat the fruit the primates drop or discard.
Piglets are born with a tawny striped coat that fades to grey within weeks. Sows raise 4–6 young per litter and are protective but not aggressive unless a human gets between them and their young. On forest trails, give any sow with piglets a wide berth. Bearded pigs are listed as Vulnerable on the IUCN Red List; subsistence hunting across Borneo has reduced their numbers outside protected areas significantly. Bako's relatively undisturbed forest supports a healthy resident population.