A once-blind female orangutan who regained her sight with surgery has returned to the rainforests of Indonesia's Sumatra island, but with only one of her young twins, an environment group said.
Gober and her infants—Ginting, a female, and Ganteng, a male, who will turn four this month—were released on January 5 to a conservation forest as part of a reintroduction project by Swiss-based PanEco's Sumatran Orangutan Conservation Programme.
"Sadly, the plan to release Gober and both of her twin infants together did not work out as hoped," a statement from the group said.
"Gober struggled in the trees with two infants to watch out for. It was not long before she seemed to give up trying, and poor little Ganteng was left behind," it said.
"Whilst Gober and Ginting subsequently coped perfectly well, travelling through the canopy, finding food and building a huge nest for the night, little Ganteng spent his first night in the forest alone and afraid, cold and wet."
Ganteng had since been taken back by the conservation programme's staff.
PanEco conservation director Ian Singleton said the carers were shocked that Gober would abandon her son.
"No one believed she would leave one of her twins behind, at least not so soon after release. We're all a bit stunned at just how quickly it happened," he said.
"Despite obvious disappointment that it didn't go as planned, I still think we can consider Gober and Ginting's release as a huge success, and we must now ensure Ganteng gets out there with them eventually as well."
The blind Gober first made headlines in 2008, following her rescue by the Sumatran Orangutan Conservation Programme after she was found raiding farmers' crops for food.
She was then placed at its quarantine centre near Medan, North Sumatra, where she mated with a male orangutan Leuser.
He was also blind after being shot at least 62 times with an air rifle before being brought into the programme's care.
The pair gave birth to the twins, which was considered rare.
Gober again made news after regaining her eyesight following a "groundbreaking" cataract surgery in 2012, paving way for her release into the wild.
More than 50 orangutans have so far been freed in Jantho under the orangutan reintroduction project.
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