He's hairy, boisterous and kids love him but to Perth Zoo, Semeru symbolises something much more...hope.

Semeru the Sumatran orangutan is being trained to climb a Ficus tree, build a nest, eat new foods and even understand Indonesian as he prepares to make history as the first male orangutan released into the wild from a zoo.

Perth Zoo achieved a world first in 2006 when the first female orangutan Temara was released into a protected part of Indonesia.

The zoo's chief executive Susan Hunt says there are only about 6,000 Sumatran orangutans left so the zoo, as well as breeding, developed a release program.

"We've got a really critical issue and with Sumatran orangutans it's just too serious not to do anything."

The orangutan keeper Kylie Bullo, who has been working with the animals for 10 years, says it's hard to see them go.

"You form a very, very close bond with them, and I mean you really spend more time with them as a keeper than you do your own friends and family so they really become a big part of your life."

The six and a half year old is already trying to escape from his overprotective mother and Ms Bullo says he was specifically chosen for the release program.

"You have to pick orangutans that are very mentally healthy and can adapt, not all orangutans can. We couldn't release all of our orangutans so we pick them according to their personality and how smart they are."

Ms Bullo says she's confident Semeru will do well in the wild.

"It's a soft release, so we follow them and give them back up food if they need it. They're not just dumped in the jungle and expected to be fine. It's a long process."

She says Temara, an adult female, has responded well to being in the wild.

"We give them the highest quality of care at Perth Zoo but you can't beat a rainforest.

"You know, Temara wakes up every morning and what she does is her choice and that's the most power you can give an animal and the highest welfare so even though we think we look after them well here, I don't think really anyone could say it's better than the rainforest."

Kylie says she hopes other zoos will adopt a similar program in the future.

"We definitely hope that other zoos would take this on board and the best way to protect the orangutan is to save their habitat so they're going into the protected area."

"That's our aim and once we've released Semeru, we'll have two orang-utans that have gone out and we're also putting a transponder in Semeru which is new technology that's been developed so we can track him and if he does evade the trackers after some time, we could do searches for him, so I think this would probably give other zoos more confidence as well if they can track their animals."

Conservation key

The Perth Zoo is the most visited zoo per capita with almost 640,000 visitors last year.

Susan Hunt says the zoo uses the crowds as an opportunity to engage the community in conservation.

"With all those visitors through the gate, that's a great vehicle for getting them involved in conservation, to remain relevant and keep demonstrating that we are actually making a difference.

"I would hate it if the zoo moved backwards to be just a place you came to look at the giraffe and elephants because they're weird because they're not.

She says the zoo linked up with the only orangutan reintroduction program in Indonesia.

"The only remaining Sumatran orangutan population is in Aceh Provence which is in the north of Sumatra, and what this program is doing is creating another population of orangutans."

Susan says for the zoo to continue such programs, State Government funding needs to keep coming.

"We have been fairly resource-limited at Perth Zoo.

"We haven't had big dollars. In other zoos, for example, the elephant exhibit at Taronga Zoo was some $40 million, our elephant exhibit was upgraded a few years ago and it cost us about $4 million so we haven't had big money."

Ms Hunt says the zoo needs to keep upgrading and that needs capital.

"Unless we can keep our facilities... number one for the welfare of the animals and two, as a vehicle for people who want to see how beautiful the environment here at the zoo is, that's going to be pivotal to keeping them (people) coming."