Claire Harvey, The Jakarta Post, Denpasar, Bali

There is an ugly little secret in a beautiful corner of Bali.

An adorable baby lion cub, emaciated and covered in sores, is chained by the neck inside a tiny, stinking cage.

Not far away his parents, both proud African lions, lie on the filthy concrete floor of another cage, chained by their necks to posts.

The baby's father has an open wound on his head and growls angrily at anyone who approaches his cage. The lioness is not allowed to see her baby, who spends all his time alone in his dark little cell.

This is Perancak Tourist Park, a private zoo which animal rights activists say must be closed immediately.

A recent report by the World Society for the Protection of Animals (WSPA) declared Perancak Tourist Park the worst of 10 Indonesian zoos visited by investigators over the past two years.

Perancak was "beyond rehabilitation and should be closed as soon as possible", the WSPA report said.

Animals were kept in pitifully small cages, hygiene was completely neglected and the animals showed symptoms of severe mental disturbance, the investigators found.

The zoo managers even offered to sell one of the seven African lions then in residence to investigators. "Several of the lions were chained by the neck and others had open sores which had been left untreated and were infested with maggots," the report said.

The zoo did not have a valid permit, but kept several types of protected species, including eagles, hornbills and crocodiles.

When The Jakarta Post visited Perancak this month, things had not improved. The eagles are no longer there, and five of the seven lions have been transferred to Surabaya Zoo by the Forestry Department.

A skinny, nervy pig-tailed macaque runs loose around the park. Around its belly is a broken chain. In a corner of the zoo is the answer to its escape -- the wire surrounding its empty cage is torn open and the other end of the macaque's broken chain lies on the floor.

Now it runs wild, climbing on the cages of other animals and sidling up to visitors in the hope of being fed. It is in luck -- a man is holding a packet of crisps. Within seconds the macaque snatches them and scampers into a tree with its prize.

The macaque seems at first to have little fear of humans -- but when one visitor bends to pick up a stick it squeals in terror and sprints out of reach. Clearly this creature has learned from experience to fear humans wielding sticks.

Activist Purwo Kuncoro, from the Bali division of Animal Conservation for Life or Konservasi Satwa Bagi Kehidupan (KSBK), is horrified by Perancak.

"The conditions here are terrible," Purwo says. "Many of these animals cannot be saved. They have been so badly neglected that many of them would have to be euthanized."

Purwo and fellow activist Wita Wahyudi have visited Perancak dozens of times in their research for the report, which was a joint project by WSPA and KSBK.

They have learned the owner of Perancak Tourist Park, about two hours' drive east from Denpasar, is local businessman Murah Hardono. But the family who ostensibly runs the zoo, selling tickets and snacks and feeding the animals, say they have no telephone number or address for him.

Officials of the Department of Forestry say they, too, have been unable to trace Murah.

"The biggest problem in Indonesia is a lack of education about animal cruelty," Wita says. "We have never educated our children to care for animals. Even in kindergarten, children learn that if they want to see a bird, they should put it in a tiny cage."

At Perancak, Purwo crouches before the dank cage of a wild boar. The animal, its ribs clearly visible through its skin, wallows in a thick gray puddle of mud which takes up half its cage.

"We don't want all zoos to be closed down," Purwo says. "We realize that zoos are necessary for education and for breeding some species, but they do not have to be like this."

Next door to the wild boar's cage is a cassowary. This enormous bird, perhaps 1.7 meters tall, is kept in a cage no bigger than three meters square. It darts about nervously, banging itself against the walls.

Four peacocks stand in a large, bare aviary and in a malodorous pond behind a wooden fence, several large crocodiles lurk in a dark-green pond. Near the crocodiles lie the remains of their food. The bloody mess of flesh looks like it might have been a dog.

Perhaps the saddest sight at Perancak is the cage which once housed an animal that has disappeared to who knows where.

At one end of the row of cages a glass-walled room sits empty, its roof missing. This room is tiny -- surely not more than four meters square. What sort of animal could be kept in such a tiny place? Surely something which did not need much room to move.

A tumbled-down sign reads: "Kangaroo".

For a kangaroo, the famous high-jumping, athletic Australian marsupial, being trapped in a room like this must have been torture.

Where has it gone? Nobody at Perancak can say -- but whatever fate befell the Perancak kangaroo could not have been worse than a life in this place.