1. Why release a zoo-bred orang-utan?

Each year the Sumatran Orangutan Conservation Programme (SOCP) currently releases around 20 orangutans – all former pets or orphaned orangutans - into Bukit Tigapuluh National Park. This low number is due to the relatively small number of Sumatran orangutans held illegally, unlike the situation in Borneo where the three orangutan care centres presently hold around 1,000 Bornean orangutans. As distinct from Borneo, there is a lot of empty suitable orangutan habitat in Sumatra.
 
SOCP plans to release into Bukit Tigapuluh at least 200 orangutans – the number of Sumatran orangutans believed to be held illegally – to establish a viable founder population. It is estimated that Bukit Tigapuluh has the capacity to carry at least 750 orangutans. This means that there is plenty of scope, in terms of carrying capacity, and the potential to include suitable zoo-bred Sumatran orangutans to increase the release numbers and genetic diversity of the Bukit Tigapuluh population. 

The planning and investigations undertaken by Perth Zoo prior to the decision to include Temara in the SOCP program were undertaken with the highest levels of due diligence. The release of Temara is based on Perth Zoo’s vision to actively contribute to conservation in the wild and is consistent with the IUCN Reintroduction Guidelines.

2. Why was an adult orangutan chosen for release instead of a young orangutan?

Naturally raised by her mother Puteri, Temara was chosen as a highly suitable candidate for this program by staff that have direct experience with orang-utan release programs. Thirteen years old, Temara is at the natural age of dispersion (when an animal leaves its mother) for a female orangutan. She has had a secure and nurturing upbringing and is an intelligent and independent orangutan. Temara is active, shows good problem solving skills and eats a wide variety of food. She is also in excellent mental and physical health.

Temara is used to human company which means she can be provided with human support in the forest. However, she is also fairly wary of humans which, coupled with her independent nature, will hopefully make her move away from the release station over time and not be reliant on the trackers for extra food. Temara’s intelligence and curiosity should encourage her to explore the forest, travel and eat different foods including leaves. All of these are positive traits in terms of releasing an orang-utan and make Temara a prime candidate for this program.

All of the juvenile orangutans released so far at Bukit Tigapuluh National Park have lost their mothers and have usually experienced physical and psychological trauma which has an impact on how they cope when released back into the forest. This is not the case with Temara. Temara was born at Perth Zoo as part of a long-standing successful breeding program for this critically endangered species. The orangutan colony at Perth Zoo is set up to provide the natural social and activity patterns of wild orangutans. Temara has been exposed to three nursing mothers to provide her with the maternal learning experiences that she will need in the future. 

For zoo orangutans to be genuinely considered a back-up option for wild populations there must be a proven way of transferring their genetic material back to wild-living populations. It is still early days in terms of proposals for embryo transplants and AI into wild females and there are severe limitations with the practical application of these methods. The re-introduction of individuals may be the only feasible option. It would not be ethical to remove a baby orangutan from its mother to join a re-introduction program, so we need to know if an orangutan at the natural age of dispersion can make the transition to the wild. The age of natural separation from a mother may be an advantage as the animal is naturally physiologically and psychologically ready for independence in a new environment. Sound mental health appears to be an underpinning necessity that determines if an orangutan can achieve the necessary forest skills and social learning that successful reintroduction requires. All of our previous information on adult orangutan reintroductions relates to animals that have been kept in totally inappropriate environments (i.e. kept as pets, removed from their mothers as babies, subjected to physical and mental trauma etc).

It is understood and acknowledged as a possibility that Temara may not fully adapt to her wild environment. If this is the case, she will remain supported in the rainforest with ongoing assistance. As part of their commitment to orangutan conservation, Perth Zoo and the Australian Orangutan Project are working with SOCP to provide ongoing support to the orangutans that do not assimilate into the wild.  This includes the development of an open sanctuary near Bukit Tigapuluh where these orangutans will be provided with long-term support in the forest. The offspring of these orangutans will have the opportunity to grow up wild and contribute to the wild-living populations at Bukit Tigapuluh.  Perth Zoo and AOP have allocated funds in 2006-07 to SOCP to develop this open sanctuary.  

3. What is the benefit of Temara’s release to orangutan conservation?

In the short term, the release of Temara provides the opportunity to contribute genetic diversity within the release population of Bukit Tigapuluh which is totally isolated from the wild Sumatran orangutan population.  This is consistent with IUCN guidelines for orangutan reintroduction.  Due to orangutans’ slow reproduction and their natural social system, the ability for male orangutans in the Bukit Tigapuluh to contribute genetically is very restrictive. Introducing a reproductive female to this environment provides the opportunity for the female (Temara) and the resident males, who may not otherwise have the opportunity, to make a genetic contribution.

If the scenario for the Sumatran orangutan painted by Carel van Schaik in 2001 is right (and he called it the most realistic scenario), the Leuser population - the only remaining viable population of Sumatran orang-utan - will be reduced to 1,500 individuals in the next decade. It is likely that in this situation conservationists may have to start genetic management of wild populations. In that case, having surplus genetic stock of wild living orangutans, separate to the depleted original wild population, will be extremely beneficial. 

4. What kind of pre-release/pre-transfer training is being conducted?

A comprehensive pre-release plan is being implemented at Perth Zoo.  Developed in close consultation with SOCP, the program has been built on all present material available on Sumatran orangutan management and on the personality of the specific release animal.  As part of this pre-release plan, Perth Zoo keepers have been introducing changes to Temara’s diet and routine. A wider variety of leaves and Indonesian fruits are being introduced to her diet and she is being given smaller amounts of food every one to two hours during the day to mimic rainforest feeding patterns. Her vegetable ration is being reduced and leaf material increased to represent more closely what will be available to her in the Sumatran rainforest. Temara is also being given extra vegetation to construct her sleeping nests and being given greater access to the outside exhibit overnight to accustom her to sleeping outdoors. Live termites are being introduced to her diet as these are readily available within Bukit Tigapuluh. Temara also has access to a mature 30m high fig tree for climbing and nest making. This is improving her fitness and muscle tone to assist with the transition to tall rainforest trees. Hand injection and crate-training have also commenced in preparation for her pre-shipment health checks and transport.

On arrival at Bukit Tigapuluh, Temara will have the support of staff with high level expertise in orangutan management including Perth Zoo’s Exotic Curator Leif Cocks, Perth Zoo’s Head Orangutan Keeper Kylie Bullo and two especially picked Indonesian technicians who will continue to assist with Temara’s adaptation. Temara’s introduction process will be consistent with the successful format and protocol developed by the Sumatran Orangutan Conservation Programme.