Seventeen rare pygmy kangaroos are returning to the Papuan rain forest after being rescued and acquiring from illegal traders and private zoo.
It is unknown how many of the mammals, which can grow up to a meter (yard) long and weigh 12 kilograms (26 pounds), still survive in the wild.
The 17 animals being released were born to six males and females cared for by the Cikananga Animal Rescue Center on West Java where they have been reared to survive in their natural habitat, said spokesman Resit Sozer.
They will gain their freedom on Tuesday, but will face predators such as giant pythons and local poachers who eat their meat or sell their hides.
The World Conservation Union has placed the species in its "vulnerable" category, meaning they face a high risk of extinction in the medium-term. The organization has not specified the estimated time period.
The trade in rare and exotic animals from Papua and other areas of Indonesia is rampant, due largely to poor law enforcement. Rapid deforestation and commercial development also threaten species such as the Sumatran tiger, elephant, rhino and orangutan.
"Illegal trade can't be stopped without the cooperation of buyers and neighboring countries. If the buying continues, we will never be able to stop it," said Adi Susmianto, a senior official at the Forest Ministry.
Little is known about the kangaroos, known as dusky pademelons, or Thylogale brunii. They belong to a family of seven kangaroo-like mammals. The Indonesian kangaroos are generally found in forests in the southeastern coast of the island of Papua, split between Indonesia's West Papua and Papua New Guinea.