Gibbons Go Wild

Major Threats

The most significant threat is the decline of habitat as the native forests of Java have been cut down for logging, agriculture and development. It is also common for juveniles to be caught and sold in the illegal pet trade.

The Aspinall Foundation in Java

We began our work in Indonesia with Javan gibbons in 2009, before extending our projects to include other species.

After several years of research our Javan Primate Rescue Centre was established and, in 2011, received its first intake of Javan gibbons in need of rehabilitation. Since then we have released over 80 primates back to a life in the wild. A combination of Javan gibbons, Javan langurs and grizzled leaf monkeys, they have included both rehabilitated animals from the pet trade in Indonesia and relocated animals captive bred at our two parks in Kent. 

In February 2016 we were delighted when a wild Javan gibbon gave birth to our first baby fathered by a young male rescued and subsequently released back to the wild. This birth marks an important affirmation that reintroduced gibbons can thrive and breed once returned to the wild, as we have seen with langurs too. It has also confirmed another important factor for future success at our Primate Project in Indonesia, which is that certain species in particular benefit from being released as individuals rather than in family groups created in captivity.  

Preparations for Transfer

Prior to leaving our wildlife park in Kent diets are gradually changed to bring them closer to the food they will have in their native homeland, and each animal is given a series of health checks over a period of several weeks. This process includes blood tests to ensure they are not only fit to undertake the rehabilitation process, but also that they do not harbour any diseases that may be transferred to the wild population post release.

We were already aware many of our Javan gibbons would prove positive for a particular strain of Hepatitis B, but for some time the unanswered question was where had they acquired the disease, and was it prevalent in the wild population? It took several years to carry out the necessary research and close co-operation with the Javan authorities to find the answer – not only is the virus widespread in the wild population but it is very specific to the species – identified as ‘Javan gibbon Hepatitis B virus’. To find out more please read our blog.

What Awaits Them

Once the five Javan gibbons reached our centre in Java they entered a rehabilitation process. Our team at the centre monitored them as they adjusted to their new surroundings. There is no set time allocated to the pre-release stage as it can vary from animal to animal, but we anticipate 4- 6 months before release into the wild. Our team will continue to monitor their progress once released, and we hope future updates will include details of new mates and, ultimately, the birth of the next generation.