The Javan slow loris is not, as its name suggests, the speediest creature in the animal kingdom. These melon-sized mammals move at an average speed of around one mile an hour, while they can perch motionless on a branch for an entire morning or afternoon.
Researchers believe they may even slip into torpor – a kind of hibernation – when it gets chilly.
Sadly, the recent decline in the Javan slow loris population has been anything but sluggish. With numbers plummeting by at least 80 per cent over the past three decades, the Javan slow loris is now one of the world’s 25 most endangered primates. In Indonesia – which is home to the Javan slow loris and five other slow loris species – these omnivores are now in serious danger of extinction.
“Their cuteness has been a major factor in their decline”
“With their doe-eyed, button-nosed faces and cuddly appearance, the Javan slow loris and other loris species are outwardly endearing,” says Nur Purba Priambada, a wildlife veterinarian and animal management supervisor working for NGO Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI). “Sadly, their very cuteness has been a major factor in their decline, because people want to keep them as pets. Efforts to address the illegal trade in slow lorises, which are critical to their conservation, are hopefully bearing fruit just in time.”
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The most captivating slow loris feature is their brown saucer eyes – an adaptation that facilitates their nocturnal lifestyle. The Javan slow loris, which is endemic to the Indonesian island of Java, spends most of the day asleep, venturing out at night to mostly feed on tree gums and saps. Like all slow lorises, it is an arboreal species, found in primary and secondary forests, bamboo and mangrove forests, and even commercial plantations. It uses vines and lianas to move from tree to tree, crawling across canopies, rather than swinging and leaping like other primates.
Unfortunately, the species is being forced into smaller and smaller pockets of increasingly fragmented forest. Java is home to some astonishing biodiversity, but also happens to be the most populous island in the world, with more than 130 million people living on a piece of land the size of England. With human pressures putting a significant strain on the island’s wild nature, only 20 per cent of historic Javan slow loris habitat is now left intact.
Saving the species
In April 2024, Indonesian photojournalist Garry Lotulung found himself in the rainforest of Mount Halimun Salak National Park, located around 100km south-west of the Indonesian capital Jakarta. He was following a procession of keepers carrying metal cases, as well as volunteers and veterinarians, strung out on the forested slopes ahead of him – many of them working for Indonesia’s Natural Resources Conservation Agency (BKSDA) and YIARI. Each metal case contained a Javan slow loris, ready to be returned to the park’s prime loris habitat.
While habitat loss is an ongoing challenge for those involved in Javan slow loris conservation, this challenge has been hugely compounded by the illegal wildlife trade. Most of the lorises being transported on the backs of the keepers had been rescued by the BKSDA.
“Over the past 10 to 15 years, a craze for keeping Javan slow lorises as pets has developed, driven by social media platforms such as YouTube, TikTok and Instagram,” explains Lotulung, who has worked to raise awareness of the issue since 2020. “Despite the fact that the Javan slow loris is strictly protected, many videos showing them being kept as pets have gone viral, driving up demand. Sometimes they’re kept as pets by Indonesian people, but they also end up overseas, in places such as Japan.”
“Habitat encroachment means Javan slow lorises are often found looking for food or shelter in plantations and bamboo forests, as well as in settlements,” adds Nur Purba Priambada. “Hunters simply pick them off trees, crate them up, and eventually they end up in markets. A hunter might get paid $10 or $20 for a loris, but by the time they’re purchased by the owner, they can cost ten times as much.”
When Javan slow lorises are confiscated, or abandoned by their owners, they often end up at YIARI’s Primate Rehabilitation Centre in the town of Ciapus, west of the city of Bogor. The largest rescue centre for slow lorises in Indonesia, it is also the only one in the country specialising in their rehabilitation and release. To date, the centre’s dedicated staff have saved more than 1,000 slow lorises, with more than 670 returned to the wild over the past 14 years.
Cute but deadly
Rehabilitating a Javan slow loris that has been kept as a pet is far from straightforward. Belying its benign outward appearance, the species sports some bizarre evolutionary adaptations. Of these, the capacity to inflict a highly venomous bite, is perhaps the most complicating factor.
“Slow lorises are the only venomous primate, and one of only a handful of venomous mammals,” explains Nur Purba Priambada. “They are remarkably territorial animals, and researchers believe they use their venom, which actually rots flesh, to settle disputes with other lorises. When they’re caught, hunters and middle men frequently clip off or completely remove their teeth – using nail clippers, wire cutters or pliers – to make them easier to handle, and to prevent them biting other captive lorises.”
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This brutal practice frequently sees Javan slow lorises die from blood loss and infection before they’re sold. It also means that many of the lorises that end up at the YIARI rehabilitation centre are sick and stressed. Their teeth are often infected and need to be extracted, which invariably condemns them to a life in captivity.
“On top of this, these animals are totally unsuited to being kept as pets in small cages,” says Nur Purba Priambada. “Keeping them in bright conditions causes pain and suffering, their poor diet causes other problems, and they lose the ability to feed themselves.
“During rehabilitation, we give them the right food and enable them to re-learn their hunting skills. We give them care at night, which means we have to become nocturnal, too. We want to give all Javan slow lorises that could survive in the wild a second chance in nature, but they need to be healthy first.”
Documenting the slow loris
For Garry Lotulung, the opportunity to document the return of a cohort of rehabilitated Javan slow lorises to the wild was too good to miss. The resulting hike into the tropical forests of Mount Halimun Salak National Park provided a rigorous test of both his photographic and physical skills.
“It was a two-hour trek to the release area base camp, and the keepers walked very fast,” he recalls with a smile. “I often had to run ahead, uphill, to get the shots I wanted. Once the pre-release acclimatisation enclosures were set up, I focused on capturing the nocturnal feeding. I fell over many times on slippery paths in the darkness, but it was absolutely worth it. It’s very rare to be able to photograph the Javan slow loris at night.”
In partnership with Indonesia’s Ministry of Environment and Forestry, YIARI carries out habitat surveys to identify the best sites to release rehabilitated lorises. There needs to be enough food and trees, community support and protection, as well as other slow lorises living wild in the area. After three to five days spent in acclimatisation enclosures – during which time they’re fed, monitored, and fitted with radio collars – the animals are set free.
“We keep track of the released lorises for several months,” says Nur Purba Priambada. “Their survival rate is usually no more than 40 per cent, but it’s the best we can do.”
“I really believe they can be saved from extinction”
Lotulung is cautiously optimistic about the future of the slow loris. “It’s heartbreaking to see the condition of these lorises when they come to the rehabilitation centre, which is why I will keep raising awareness of the illegal pet trade issue. But having seen the work of the YIARI team and their partners first-hand, I really believe they can be saved from extinction.”
Under its partnership with the Indonesian government, YIARI’s work to conserve the Javan slow loris goes beyond returning animals to health and to the wild when they can. The NGO is also involved in wide-ranging efforts to raise awareness and promote coexistence – organising educational and community engagement initiatives, social media campaigns and research programmes. They also support the government’s law enforcement efforts.
“We want as many people as possible to understand that the trade in these animals for pets is cruel, illegal and hugely destructive,” says Nur Purba Priambada. According to data from YIARI, at least 5,500 Javan slow lorises have been observed in physical and online markets since 2012. This activity peaked in 2017, when more than 900 were traded.
“We still lack accurate information about population numbers, but over the past few years we’ve seen fewer and fewer Javan slow lorises with clipped teeth, and we’re seeing fewer and fewer animals arrive at the rehabilitation centre,” says Nur Purba Priambada. “I like to think this is because our collaborative efforts at combatting the illegal trade in these animals are proving effective. I hope the trend will continue – not only because this is an amazing animal in its own right, but because slow lorises are a vital part of Indonesian wild nature.”
Main image: A slow loris is seen in its cage iron box before the released in the Gunung Koneng Part of Gunung Halimun Salak National Park in Sukabumi, West Java, Indonesia / Credit: Garry Andrew Lotulung/Anadolu via Getty Images
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