- Thailand is home to four gibbon species, all of which are listed as endangered due to habitat loss and wildlife trafficking.
- Rescue, rehabilitation and release projects play an important role in protecting gibbon welfare and restoring ecosystems, but effectively rehabilitating and releasing gibbons is both difficult and costly.
- Two organizations, the Gibbon Rehabilitation Project and Wildlife Friends Foundation Thailand, have been rehabilitating gibbons in Thailand for more than 20 years.
PHUKET, Thailand — The air is thick and sticky in the forest surrounding the Gibbon Rehabilitation Project center. Thanaphat Payakkaporn, head of the project, bends down to pick up the discarded shells of langsat fruits, a sign that wild gibbons have been in the area. As a series of loud, melodic whoops echo through the jungle, Thanaphat looks up at the canopy and smiles. “Bo’s son comes to visit him sometimes,” he says.
Bo is a 37-year-old white-handed gibbon (Hylobates lar), rescued in 1993 after being captured and kept as a pet for five years. He’s one of around 400 gibbons that the GRP, led by Thanaphat, has rescued and rehabilitated. At least 100 have been successfully released in the provinces of Chiang Mai and Phuket, where wild gibbon populations had previously been decimated by poachers. Bo’s son is one of these gibbons, but Bo himself has proved difficult to release. Despite seven attempts, he keeps returning to the center or venturing out of the forest in search of humans. He’s now a permanent resident at the rehabilitation center.
Thailand is home to four gibbon species: white-handed or lar; black-handed or agile (Hylobates agilis), pileated (Hylobates pileatus) and siamang (Symphalangus syndactylus), all now listed as endangered due to rampant poaching and habitat fragmentation in the latter half of the 20th century. In parts of Thailand, including Phuket, wild populations were hunted to extinction, as captive gibbons became highly profitable photo props in the tourism industry. Today, stricter law enforcement has curbed this practice, but the illegal trafficking of gibbons continues, mostly to supply a growing exotic pet trade. Infants are considered the most valuable. According to Thanaphat, this means that for every poached gibbon, “seven have to be killed in the wild, because they have to kill the entire family to get a baby.”
In Phuket, there’s now a small population of white-handed gibbons living in the wild, thanks to the GRP’s reintroduction efforts. But rehabilitating and releasing gibbons is notoriously difficult, and the team’s initial attempts in the 1990s resulted in a high mortality rate.
“Gibbons are my brothers,” Thanaphat says. “Whenever I failed and they died, I felt I was responsible for my brother’s death.”
Over the years, the GRP has refined its methods, learning from the project’s own accumulated data and working with the IUCN, the global wildlife conservation authority. First, the team quarantines and conducts health tests on the rescued animals, checking for any infectious diseases that could be transmitted to others. If the tests are clear, the gibbon is moved into the rehabilitation center.
Here, rehabilitation involves a series of techniques to “teach gibbons how to be wild again.” For example, obstacles may be placed on the floor of the enclosure to encourage gibbons that were previously trained to walk to start swinging. Tall camouflage screens are draped around the enclosures, and a rope-operated feeding system is used to minimize the gibbons’ interactions with humans. “We have one golden rule,” Thanaphat says. “Whenever they’re in the rehabilitation zone, we never touch them again.”
Another important part of rehabilitation is the pairing process. “Releasing a single gibbon is like going to a bar alone,” Thanaphat says. Lone males in particular, he says, are likely to initiate aggression toward other males in the wild, with catastrophic consequences. Finding the right match for each gibbon is a long and arduous task and requires daily observation of the gibbons’ interactions. The team has built “love tunnels” between enclosures to enable new couples to meet while still retaining their own space. After gibbon pairs have mated and reproduced, the family can be considered for release.
When identifying a release location, a range of criteria are evaluated, including ecological conditions, climate, and local attitudes toward wildlife. The presence, density and species of existing wild gibbon populations are also taken into account. All releases are conducted within the species’ historical range.
Once a family is ready, its members are translocated to the site and released. For at least two months, a small team stays in the location to oversee the gibbons’ adaptation to the wild and to steer them away from danger. They gradually introduce the gibbons to the locally available wild food, and ensure they don’t veer into human settlements or pick fights with other gibbon families.
According to a 2015 study on the GRP, between 2002 and 2012 a total of 30 gibbons were released in Phuket and 11 were born in the wild within the reintroduced population. Out of these 41 gibbons, 18 died, disappeared, were poached, or returned to the rehabilitation center after release. No later data are available publicly, and Thanaphat says that in recent years the team has stopped publishing academic research or focusing on success metrics. “It’s bad to say this, but it takes too much time,” he says. Nevertheless, the team still keeps detailed records internally. And according to Thanaphat, at least 30 gibbons have been successfully released or born in the wild in Chiang Mai since 2014, with 66 in Phuket since 2002. In Phuket, some have reproduced over multiple generations, leading to a small, self-sustaining population. “We have lost count of the total number,” he laughs.
Historically, primate rehabilitation and reintroduction projects have had a limited success rate. A 2015 study in the Natural History Bulletin of the Siam Society praised the GRP as the “only reasonably successful attempt so far” to release gibbons in Asia, while cautioning against “the naïve view” that small-scale rehabilitation or reintroduction projects can address the wider issues affecting gibbon conservation. The GRP has reintroduced gibbon populations and restored forest ecosystems in a small section of the historical range, and it has sensitized local and tourist communities about the importance of protecting gibbons. But it would be unrealistic, researchers have said, to expect it to impact the overall conservation status of the species.
Wildlife Friends Foundation Thailand: Gibbon rehabilitation islands
Some 600 kilometers, or 370 miles, north of Phuket, near the tropical rainforest of Kaeng Krachan National Park, is the Wildlife Friends Foundation Thailand (WFFT) rescue center, the only other gibbon rescue and rehabilitation initiative in Thailand listed in the IUCN Primates Specialist Group’s database. Among hundreds of other animals, the center currently houses 96 gibbons rescued from the tourism and exotic pet trades. Many have suffered from serious injuries and psychological trauma.
“This is Jub jib,” says Tom Taylor, head of operations. A dark-eyed, white-handed gibbon looks out of a large enclosure, her body swinging rhythmically as she holds onto a rope. “She was kept for 15 years in a guy’s house in Bangkok. He was feeding her human antidepressants every day to keep her calm … It’s one of the most harrowing cases we’ve seen — we had to wean her off the drugs.”
The WFFT has its own rescue team. Technically, Thai law doesn’t allow NGOs to conduct animal rescues, but the team has found ways of doing this legally through collaboration with the government’s Department of National Parks, Wildlife and Plant Conservation. Once a rescued gibbon has been quarantined, given a health check and treated by veterinarians at the WFFT’s on-site wildlife hospital, the matching process begins. “We will put the potential mate in the smaller enclosure, leave both tunnels closed for a few days and observe them,” Taylor says. “Are they singing together? Are they looking at each other? … We’re very experienced in matching gibbons, so it’s a slow process but we know what we’re doing.”
The center rehabilitates gibbons of all four native species, plus some white-cheeked and golden-cheeked gibbons (Nomascus spp.), indigenous to Laos, Vietnam and Cambodia. Taylor says that when possible, matches are made within the same species, especially if there is a possibility of release in the future. “Any of them that aren’t going to go back to the wild, we [let them match with] another species for welfare purposes,” he says. To prevent cross-species pairs from breeding, the veterinary team inserts temporary birth control implants into the females.
Between 2010 and 2011, the WFFT collaborated with Mahidol University to release two gibbon families in the northern province of Mae Hong Son. Though the follow-up data were never published, the release was a success, according to WFFT records from the time — that is, the gibbons survived. The team hasn’t carried out any releases since, but has instead focused its efforts on rehabilitation.
To support the rehabilitation of some of the “wilder” gibbon families, the WFFT has built 20 small islands on a lake within the premises, where the gibbons can live arboreally and with minimal human interaction. It has also built electric fences around two sections of the forest, turning them into gibbon “fields.”
“This was already forested, so it is an ideal place for the gibbons,” Taylor says. In recent years, changing weather patterns and recurring bouts of drought have dried up parts of the lake, and the team has been forced to move some of the gibbon families back into the enclosures. “It’s the second time in five years we’ve had to remove the gibbons from the islands,” Taylor says dejectedly. For now, both fields and six of the islands remain habitable. The gibbon families that occupy them are ideal candidates for a potential future release.
Future outlook for gibbon rehabilitation and release projects in Thailand
The trafficking of captured gibbons to feed a growing exotic pet market (for which Thailand is a global hotspot) continues to be a major threat to the conservation of the apes. In this context, Susan Cheyne, vice chair of the IUCN Primate Specialist Group’s Section on Small Apes and co-author of the IUCN’s Best Practice Guidelines for the Rehabilitation and Translocation of Gibbons, says there’s an ongoing need to “return captured gibbons to the wild,” or, when that’s not possible, to “give them the best possible life in captivity.” Wild-like captive environments, such as the WFFT’s gibbon islands, serve an important purpose in providing both “an enriching home” and “training ground to assess the suitability of gibbons to survive in the wild prior to release,” according to Cheyne.
The WFFT team is currently in talks with partners to initiate a new gibbon release project, this time near Petchaburi. “We are hoping that in the future we can start releasing gibbons again, and we’d love to try to do it in some of the protected forest areas around here,” Taylor says. “But it has to be done properly. We need scientists to work with us from a university, and we need the commitment and collaboration from the department of national parks.”
In the meantime, the GRP continues to conduct almost yearly releases in Chiang Mai province, and is currently exploring a new location in central Thailand. “At the moment we are not close to success, because there are still so many gibbons that need to be taken care of, to be paired and given freedom,” Thanaphat says. “Our ultimate goal is to shut down the project.”
Ana Norman Bermúdez is a multimedia journalist currently based in Bangkok. You can see more of her work on instagram @ana.n.b or on her website www.ananormanbermudez.com
Correction: This article was amended Aug. 9, 2024 to correct the spelling of Susan Cheyne’s name.
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