Thailand’s Pileated gibbons (Hylobates pileatus) face a new, still largely undocumented threat: illegal loggers are penetrating deep into the forests of the nation’s national parks to cut down Endangered Siamese rosewood trees (Dalbergia Cochinchinensis). While there, the poachers are feeding on the primates and other wildlife. Wildlife rangers in the country’s Thap Lan National Park have taken photos of the carnage, showing the loggers grisly harvest of gibbons and other animals for bushmeat.
Covering 2,200 square kilometers (849 square miles), Thap Lan is one of four national parks, and a wildlife sanctuary, that make up Thailand’s Dong Phayayen-Khao Yai Forest Complex (DPKY-FC). Designated a UNESCO World Heritage site in 2005, DPKY is one of Southeast Asia’s last remaining tracts of globally significant lowland dipterocarp tropical forest ecosystem. It is an important wildlife stronghold for over 800 species, including globally threatened and endangered animals such as the Asian elephant, Asiatic black bear, Malayan sun bear, banteng (a species of wild cattle), hornbills, slow loris, Siamese crocodile and Sunda pangolin.
Pileated gibbons are classified as Endangered on the IUCN’s Red List, with their numbers rapidly decreasing across Thailand, Cambodia and Laos PDR — the species’ three range states. Populations are believed to have declined by over 50 percent in just 3 generations (about 45 years) between 1970 and 2015.
Hunted toward extinction
A medium-sized primate weighing around 5-6 kilograms (11-13 pounds), Pileated gibbons live in mated pairs together with their offspring. Almost completely arboreal, the species is predominantly frugivorous, spending more than 60 percent of its feeding time on fruit.
As with other species of gibbons, Pileated gibbons sing incredible duets in the forest canopy, with their ethereal songs audible from more than 1.5 kilometers (0.9 miles) away. The females launch into “great calls”, while the males sing in overlapping responses. Naturalist and explorer Alexander Henri Mouhot (1826-1861) described “jungles full of monkeys uttering their plaintive cries” during his expedition to Southeast Asia while collecting animal specimens for London’s Natural History Museum.