ADELAIDE - An Australian zoo has put a group of humans on display to raise awareness about primate conservation - with the proviso that they don't get up to any monkey business.

A screenshot of Humanzoo.com.au, taken on January 9, 2006.[Reuters]

Over a month, the humans will be locked in an unused orang-utan cage at Adelaide zoo, braving the searing heat and snacking on bananas. They will be monitored by a psychologist who hopes to use the findings to improve conditions for real apes in captivity.

Audiences can vote for their favorite "ape" via mobile phone text messages, in the style of reality television shows, and at the end of the month, a "super human" will be selected to represent the zoo.

"They're completely mad," said one visitor to the exhibit, as the humans, who are allowed home at night, played up to the crowds and checked each other for imaginary lice.

"It's not as exciting as the animals actually, they're not really doing very much," another onlooker said, clearly unimpressed by the volunteers' shenanigans.

One of the human apes, Josh Penley, said the experiment was a chance to "get myself out of my comfort zone and to get a week off work."

Participants wear microphones in front of Web cams to allow watchers to hear the action in what has been billed as "Big Brother behind bars."

Dr. Carla Litchfield, who is conducting the experiment, has laid down firm rules for the new apes: no nudity, no rude behavior and no jumping into the enclosure spa.

Zoo vets haven't ruled out using tranquillizer darts if the humans misbehave.