Jo Cook had good reason to be wary of the latest arrivals in the large mammals section of London Zoo yesterday.

Since their evolution from the primordial slime, they have been responsible for the destruction of 844 other species, not to mention some 800 million of their own kind.

Fortunately the new humans enclosure at the zoo, situated next to five bemused Langur monkeys and four non-plussed Sloth Bears, was populated by five of the more agreeable specimens of the genus homo sapien whose main activity seemed to be playing Connect Four and listening to Radio 2 rather than the destruction of the planet.

Ms Cook, 28, a senior mammals keeper who normally spends her time looking after the needs of the zoo's bears and apes, had just returned from supplying a set of hula-hoops to ensure the "behavioural enrichment" of her new charges.

She said: "They are far more demanding than my usual animals. We have to keep them occupied and entertained - we are responsible for their welfare.

"I gave them a football this morning to run around with to do some exercise. It is quite important to keep the weight off them."

The spectacle of five of the planet's most advanced Great Ape species hanging about in swimwear on Bear Mountain, the 91-year-old Grade II-listed terraces that once housed polar bears and grizzlies, is the opening salvo in a campaign by the Zoological Society of London (ZSL), which runs the zoo, to highlight humanity's status as a "plague species".

It is estimated that there are currently nearly 15,600 separate species threatened with extinction as a direct result of human activity across the planet.

To underline the point, displays greeted visitors outside the enclosure comparing homo sapiens with chimpanzees and gorillas, noting that more humans are born every hour than the total existing population of the two other apes.

Managers were therefore unapologetic about their selection of eight largely trim and shapely specimens, including an international kick boxer and a professional dancer, to ensure maximum publicity by cavorting around the enclosure next to the bears and monkeys during open hours over the bank holiday weekend.

All similarities with that other Petri dish of scantily-clad human captives, Big Brother, were strictly superficial, the zoo insisted.

Simon Rayner, ZSL's communications manager, who dreamt up the idea of the human zoo, said: "There is a voyeuristic element but the point is to jolt people into recognising the impact of human beings on their own environment and that of other animals.

"We are saying, look, here are humans stripped down and treated exactly the same way as other animals. We are the same and the way we treat all animals has consequences."

It was a point largely lost on 11-year-old Rory McDonald, from Purley, Surrey, as he gazed past the electric fence and moat up towards the cart-wheeling human exhibits, who also include a biologist, chemist and veterinary student.

Rory said: "Cool, I want to have a go? It looks like Baywatch up there. And they even get a better view of the monkeys."

Justine Appleby, 34, a science teacher from Hertford, who was accompanying her two young sons, was among others who applauded the high-brow publicity stunt.

She said: "I did a double take when I saw them - for a split second, I found myself thinking, 'blimey, what kind of animals are they?'

"It's actually quiet a powerful message - what if we are so successful in destroying our environment that one day the only place you could see human beings is in a zoo?"

For the exhibits themselves, who will spend eight hours a day in their elevated nest before being let out to spend each night in their own beds, life as zoological curiosities was proving highly acceptable - right down to the gourmet vegetarian lunch provided by the zoo's on-site catering firm.

Simon Spiro, 19, a veterinary science undergraduate at Pembroke College, Cambridge, shivered slightly as he sat in his boxer shorts and felt fig leaves in a brisk wind.

He said: "I leapt at the chance to do this. We've been sitting around, getting to know each other, discussing a bit about the philosophy of being behind bars.

"I'm fascinated by how we perceive animals and how they see us. So this is an opportunity to be on the receiving end. In so many ways we are inferior to other animals. I wouldn't fancy my chances if I wandered in with the bears."