SURABAYA, Indonesia (AP) -- An emaciated female Sumatran tiger was in critical condition at Indonesia's largest zoo Wednesday and may have to be put down after another rare tiger died at the problem-plagued facility earlier this month.
Melani was born at the Surabaya Zoo 15 years ago and has been suffering from an undiagnosed digestive disorder for the past five years. Her weight has dropped to less than 60 kilograms (132 pounds), down from 75 kilograms and below the normal range of 75-110 kilograms. Her eyes look sunken and bones can be seen beneath her skin.
"I think euthanasia is the best option to end her suffering because it is difficult to be cured," said Tony Sumampouw, chairman of Indonesia's zoo association, who was appointed to oversee the Surabaya Zoo after the government took control of it in 2010.
He added that Melani's illness is likely the result of mismanagement and poor nutrition since she was young.
Melani is one of 10 Sumatran tigers -- the world's most critically endangered tiger subspecies -- left in the zoo following the death two weeks ago of Rozek, a 13-year-old male. He suffered similar gastrointestinal problems for four years.
Both tigers lost weight after they stopped being able to properly digest food and absorb nutrients, with food passing straight through their bodies, said Anthan Warsito, a spokesman for the zoo, which is located in Indonesia's second-largest city, in East Java. He said the exact cause of the illness remains unknown.
He said a lack of medical equipment and laboratory testing at the zoo has kept veterinarians from performing a thorough examination of Melani's condition.
The zoo's remaining Sumatran tigers, which are part of a breeding program, are kept in dirty, cramped cages along with 10 Bengal tigers. All appear healthy, but remain at great risk, Sumampouw said.
Chaerul Saleh, the WWF wildlife group's campaign coordinator on endangered species protection, said he hopes the latest tiger cases will force government and zoo authorities to do more to safeguard the animals. Strong action is needed to change the culture of neglect and corruption within the facility, he said.
The zoo -- once home to one of Southeast Asia's most impressive animal collections -- came under heavy fire three years ago after reports that 25 of its 4,000 animals were dying every month, almost all of them prematurely. A giraffe died there last year with a beach ball-sized wad of plastic food wrappers in its belly, sparking outrage among conservationists. An African lion, a bear and several crocodiles have also died at the zoo.
The zoo has been plagued by uncontrolled breeding, a lack of funding for general animal welfare and suspicions that staff members may be involved in illegal wildlife trafficking.
Associated Press writer Niniek Karmini contributed to this report from Jakarta, Indonesia.
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