Water-pipe bridges provide lifeline for critically endangered Javan slow lorises & farmers

New research published in time to celebrate Slow Loris Outreach Week (19th-25th October)

New research published last week in the journal Diversity, confirms that arboreal wildlife bridges are being used by critically endangered Javan slow lorises (Nycticebus javanicus), as well as other species of mammals and birds in Java, Indonesia.

Java is one of the most heavily deforested islands in the world. Vast swathes of tropical forest have been cleared, leaving hundreds of species at risk. Javan slow lorises – listed as critically endangered by the IUCN - are particularly vulnerable to being either exposed or captured for the illegal pet trade, despite it being illegal to capture and own them as pets.

The paper, titled ‘Implementing and monitoring the use of artificial canopy bridges by mammals and birds in an agroforestry environment, Indonesia’ details how simple wildlife bridges which also act as water irrigation pipes for local farmers growing coffee and other cash crops, are providing a lifeline for this rare but beautiful species.

Professor Anna Nekaris from Oxford Brookes University, with funds from wildlife charity People’s Trust for Endangered Species (PTES), has been studying and protecting slow lorises since 1994. In 2011 Anna established the Little Fireface Project (LFP), an NGO that conserves slow lorises, the world’s only known venomous primate. In 2016, Anna and her team installed ten bridges in the Garut District of West Java, and over two years (2017 - 2019), slow lorises were recorded making over 1,400 crossings on the bridges.

Delighted with the results, Prof. Anna Nekaris explains: “The land where slow lorises live is heavily farmed, with few trees left. To gain community support we decided to install wildlife bridges that could double as irrigation pipes for local farmers. Whilst the cost of the bridge - $30-$40 – may seem cheap to us, for a farmer whose monthly income is about $70, these bridges are pricey. The LFP covered the costs of erecting the bridges, if the farmers were happy to pay for the maintenance of the water lines. The farmers agreed and it’s been so successful that the LFP has now installed more bridges outside the original study area to ensure equality within the community.”

The bridges were put up at an average height of 4.5m and varied from several to almost 100m long, with camera traps placed at either end. Slow lorises began using the bridges 10-15 days after they were installed, whereas Javan palm civets took about 36 days. Now, both species use them regularly and happily, enabling them to safely cross from one habitat to another.

Nida Al-Fulaij, PTES’ Grants Manager, confirms the importance of the study: “PTES has been funding Anna’s work for almost 20 years, and now Anna is a valued PTES Conservation Partner, providing innovative, critical solutions to help solve our biodiversity crisis. Anna, her team and the local farmers are really pleased with the bridges, and it appears the local wildlife is too! Importantly there’s now a direct connection between benefits felt by these farmers and their community, and with the animals that live alongside them.”

More slow loris news: Wildlife Friendly Certification, slow loris use of venom & Slow Loris Outreach Week

Further new research published yesterday in Current Biology reveals that a major use of Javan slow loris venom is to injure – and even kill – other slow lorises.

The paper titled ‘Slow lorises use venom as a weapon in intraspecific competition’, details that slow lorises use venom as a defense mechanism against others of its kind, something that has previously only been seen in four other species worldwide. Only six mammals worldwide are known to use venom, but mostly to prey on other species, which makes this rare use of venom all the more unusual.

The results are from an eight-year study led by Anna, who worked alongside colleagues from the University of Queensland and Universitas Gadjah Mada (Indonesia). During the study period (2012-2020) the team tracked 82 individual slow lorises via radio collars, which revealed that both males and females are intensely territorial. In fact, 30% of all females and almost 60% of males studied showed at least one venomous bite wound, and 20% of all slow lorises captured showed evidence of intraspecific fighting.

Anna said: “Venom is known to play at least 14 distinct ecological roles, but intraspecific competition is amongst the rarest. Slow loris bites are very distinctive and are unlike those seen in other animals. Throughout this study we recorded and monitored wounds inflicted by other slow lorises, which even resulted in some animals losing fingers, toes or ears, demonstrating the potency of their venom. Fights are more common in younger animals trying to find a new territory, but this level of aggression is rare among related species of primates. This discovery of how lorises use their venom is fascinating.”

To create venom, slow lorises raise their arms over their head, where they combine oil from the upper arm to saliva in their mouths to produce venom that can then be injected with their teeth. Their teeth are removed when they’re illegally captured for exotic pets or for when they’re used as props in tourist photos. Some also believe their venom and fur heals wounds, which has led to their use in over 100 traditional Asian medicines.

Co-author Dr Muhammad Ali Imron from Universitas Gadjah Mada (Indonesia) said: “These findings have important conservation implications to stop the illegal trade of slow lorises. Biting behaviour is a very important mechanism for defence, so when their teeth are pulled out to avoid venomous bites during handling, they lose their ability to feed and defend themselves."


The LFP has also just been awarded Wildlife Friendly Certification - a certification only achieved by 26projects worldwide - that encourages a mutually beneficial relationship between wildlife and the local community.

Anna and colleagues work with over 400 coffee farmers in West Java to raise awareness of slow lorises whilst also safeguarding livelihoods. Together they plant native trees and wildlife friendly crops (such as coffee), which provides much needed habitat for slow lorises but also an income for local farmers. The new Wildlife Friendly Certification will give Javan farmers the opportunity to sell their coffee around the world, giving consumers the opportunity to buy ethical and sustainable coffee. Farmers can now sell their product at a higher price, ensuring that they receive a fair wage and are able to continue farming sustainably, benefitting both the local community and slow lorises.


Finally, Slow Loris Outreach Week (now in its ninth year) starts today and runs until 25th October. PTES, Prof. Anna Nekaris and other colleagues will be promoting their slow loris conversation work on social media in the hope that both the scientific community and the public learn more about this endangered primate and the multiple threats it faces. Watch out for the first virtual loris conference on Saturday 24 October, which can be joined here.

To get involved, follow @PTES and @littlefireface, and to find out more about PTES’ Conservation Partners and Anna’s work, visit www.ptes.org/conservation-partnership

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