SECRETIVE MAMMALS ENCOUNTERED IN TNBBBR

Our orangutan Post-Release Monitoring (PRM) team in the Bukit Baka Bukit Raya National Park (TNBBBR) spends most of their time observing our released orangutans, collecting data on how well they are adapting to their new environment. Every morning, the PRM team departs from the monitoring post and ventures into the forest to find and monitor these orangutans. Of course, the forest holds a great deal more animal life than just our orangutans. It is teeming with biodiversity, from tiny insects to secretive and often rare mammals. One of the perks of the job for our PRM team is encountering these amazing animals in their natural habitat and all their wild glory. Whenever possible, the PRM team documents their sightings with photographs. Documenting the wildlife living alongside our orangutans allows us to better understand the ecology of TNBBBR and improve current and future conservation strategies in the area. 

Recently, our PRM team documented some of TNBBBR’s most secretive and shy mammal inhabitants, the sun bear (Helarctos malayanus), the Sunda flying lemur (Galeopterus variegatus), and the Bornean slow loris (Nycticebus borneanus). 

Adept tree climbers and the smallest of the bear species, sun bears are shy animals that prefer to be left alone. Our PRM team encountered one recently while observing a released orangutan named Desi. This particular sun bear was found eating small insects in the same tree as Desi. The team observed no signs of aggression between the two species as they went about their separate business in the same tree. 

Feeding on mostly fruits, insects, honey, birds, and, occasionally, small invertebrates, these omnivorous bears pose very little threat to orangutans, but with a powerful bites and long sharp claws capable of breaking apart trees and dead wood, it’s best to keep your distance. 

Sun bears are spread throughout Kalimantan and Sumatra in Indonesia, and are found in other Southeast Asian countries, such as, India, Bangladesh, Burma, Laos, Thailand, Cambodia, and Vietnam. Sharing much of the same habitat as orangutans, sun bears often face the same threats to their survival, and are listed as Vulnerable to extinction on the IUCN Red List of Threatened Species. These threats have led to our orangutan rehabilitation centres having to house over 60 rescued sun bears in addition to our roughly 500 rescued orangutans. To provide the best possible care for these wonderful creatures, we are currently nearing completion of a large, unique, and world-class sun bear sanctuary on the same site as our Samboja Lestari Orangutan Rehabilitation Centre!  

Our PRM team also had the pleasure of stumbling across one of the more elegant mammals in TNBBBR, the Sunda flying lemur. You may not think it when you see a flying lemur (also known as colugos) in a tree beside an orangutan, but flying lemurs—along with treeshrews—are the closest living relatives of the primates! The Sunda flying lemur is only one of two extant flying lemur species, with the other being the Philippine flying lemur; a unique mammal indeed. They can be found across most of Borneo and Sumatra, a small area in west Java, and in certain parts of mainland Southeast Asia. 

While Sunda flying lemurs are skilled climbers, they are most notable for their ability to glide between trees for more than 100 metres using a gliding membrane (or patagium) that connects their necks and their four limbs. Their lightweight kite-shaped skin is the forest’s natural kite! This ability allows them to escape predators quickly and to access scattered food resources. They primarily consume leaves, but also feed on buds, flowers, fruit, and sap; thankfully not resulting in a whole lot of food resource competition for our released orangutans. 

While an assessment in 2008 listed the Sunda flying lemur as Least Concern on the IUCN Red List and they are a protected species under Indonesia law, their population size and habitat is in decline, and they are commonly hunted in many parts of their range. Bornean Slow Loris. 

Last, but not least, the PRM team recently bumped into a Bornean slow loris, one of the most weird and wonderful primate species on the planet. Found only in Central, West, and South Kalimantan, this incredible species is a nocturnal, venomous, semi-solitary primate, with a particular skill for catching and eating insects and gouging tree bark to extract the gum and sap underneath. They also enjoy drinking nectar and eating small amounts of fruit. 

As the only venomous primates in the world, and with a mouth full of small, sharp teeth, lorises inflict bites that can result in serious infection, allergic reactions, rashes, itching, muscle spasms, fever, fainting, and possibly even death. A great reason for both humans and orangutans to leave them go about their forest business in peace. 

Until quite recently, slow lorises on the island of Borneo were classified as a single species—the Philippine slow loris (Nycticebus menagensis). The Bornean slow loris is one of three separate species now thought to exist in Borneo. With the Philippine slow loris listed as Vulnerable to extinction on the IUCN Red List, you can be sure that when the Bornean slow loris is finally assessed, it will be even more threatened with extinction. This species of slow loris is found in Central, West, and South Kalimantan. All three of these extraordinary mammals face similar threats to orangutans. They all need their forest homes to be protected and restored. Like the orangutan, saving them from extinction across much of their range will require sustainable forest management as well as strict law enforcement with regards to hunting and trading. Sustainable forest ecosystems are the lungs of the world, and so much more than that, so let’s redouble our efforts for saving all of TNBBBRs beautiful wildlife.