EDINBURGH Zoo is to bring in a host of rare and endangered species in a £58 million transformation over the next 20 years.
Zoo chiefs hope the introduction of orang-utan, giraffes and kangaroos will draw thousands more visitors and make the zoo one of the most advanced in the world.
They have also pledged to do more to help endangered species and plan conservation schemes, including a breeding programme for the at-risk Indian rhino.
Plans to move Mercedes the polar bear to the Highland Wildlife Park near Aviemore or to build her a better enclosure at the zoo - with the possibility of bringing in more polar bears - are also being considered.
The revamp will see the layout of the zoo dramatically changed, with new enclosures, covered areas and viewing areas.
Giant manatees - sea cows - will be brought to a massive new enclosure planned for them near the penguin area.
The zoo will be divided into four zones, allowing people to experience the wildlife of tropical rainforests, grasslands, woodlands and the oceans.
The redevelopment will also see a railway installed to improve access to all the enclosures, after decades of complaints about climbing Corstorphine Hill.
One of the first changes will be the creation of a new chimpanzee enclosure and the introduction of interactive displays and talks by keepers.
Less visible changes such as installing new drains and water supply will also be made.
David Windmill, chief executive of the Royal Zoological Society of Scotland,
said: "We want to allow people to get much closer to the animals, and we will be trying to get rid of as much of the metal fencing as possible.
"The penguins, for example, are enclosed not to protect the public, but to keep foxes out, and the new plans will see a fox-proof fence put up around the entire site, which will be a great start to us opening up the enclosures."
He added: "Obviously there are limits . . .
but there are ways to give a much better impression of the animal's natural habitat. Our tiger enclosure, for example, has metal poles disguised as bamboo which gives people the impression that they are only separated from these animals by some plants."
The grasslands area - one of the four different "biomes" mimicking different environments - will be created at the top of Corstorphine Hill, which is one of the zoo's largest open areas and ideal for recreating an African plain.
The oceans and wetlands area will be created around the existing penguin enclosure, while the woodlands area will go between that and the top of the zoo.
The tropical forest area, which will include the new Budongo chimpanzee enclosure, will be built up the east side of the zoo.
"We will use things like ditches and water features to allow several different species to be kept in the same area," said Mr Windmill.
"Obviously they will be separated, but it will not appear that way, and so people will get a better idea of what it is like for these animals in the wild."
Conservation is a strong part of the masterplan, and later this year two Indian rhinos are expected to arrive from Basle in Switzerland, with a third coming in 2007 to start a breeding programme.
MR Windmill said that over the next three years the zoo's most popular animal, Mercedes, would be given a new living environment - either at Edinburgh or in the Highlands.
And while he said the possibility of bringing more polar bears to Edinburgh had not been ruled out, he insisted it would only happen if there was a strong conservation reason to do so - something increasingly likely given the perilous state of the animals in the wild due to melting ice caps.
Mr Windmill said: "We have had Mercedes checked over thoroughly by vets who say she's in great condition, so we are obviously doing a good job looking after her. But we fully accept that her enclosure is not acceptable in a modern zoo and so we will be looking to change that over the next two or three years.
"One option is to move her to the Highland Wildlife Park, and it would be great to see her with all that space when the hills were covered in snow. We may also build her a new enclosure at the zoo, as she could last another ten years. We will look again at the situation in 2010 and see whether there is a valid conservation argument for creating a bigger polar bear enclosure to enable us to start a breeding programme."
Creating a tank to house the manatee will be another huge task, and Mr Windmill admitted it was a long-term project, with the animal not likely to arrive at the zoo within the next ten years.
Manatees are large, grey-brown aquatic mammals with bodies that taper to a flat, paddle-shaped tail, two flippers and a wrinkled face with whiskers on the snout. Their closest relative is the elephant.
The zoo currently attracts more than 600,000 visitors a year, with most coming from within Britain, and one of the key aims of the redevelopment is to bring in more overseas visitors.
An assessment carried out by the zoo suggests the new animals and enclosures could bring in up to 900,000 visitors a year, creating more than 40m for the local economy. And work to build and staff the new habitats is expected to create more than 320 jobs.
Work on the 5.65m chimp enclosure is expected to start later this year, thanks to 1.8m funding from Scottish Enterprise Edinburgh and Lothians.
It will be linked closely with the zoo's ongoing conservation work in the Budongo Forest, East Africa's largest remaining mahogany forest and home to around 700 chimpanzees.
The zoo is currently working with researchers in the forest to study the behaviour of the chimpanzees and try to help conserve their natural habitat.
A free exhibition outlining the ambitious changes planned for the next two decades will open to the public on Saturday.