Indonesian conservationists Thursday hailed a breakthrough in efforts to save the critically endangered Sumatran rhino after a female called Ratu became pregnant in captivity.
Tests on Tuesday revealed that eight-year-old Ratu was carrying a calf after mating with Andalas, the first of only three Sumatran rhinos born in captivity in more than a century, experts said.
"We're really happy to see the ultrasound has spotted the foetus and umbilical cord in Ratu's uterus," said Widodo Ramono of the Indonesian Rhino Foundation, which is conducting the breeding programme.
"This is very, very good news... It will be the first Sumatran rhino born in captivity in Indonesia."
The two-horned forest-dwelling Sumatran rhinoceros is one of the most endangered mammals in the world, with only about 200 remaining in the wild, up to 180 in Indonesia and the rest in Malaysia, Ramono said.
Andalas was born on September 13, 2001 in Cincinnati Zoo, while Ratu was rescued in 2005 after she was chased from a forest on Sumatra by villagers who reportedly mistook her for a mythical monster and tried to kill her.
They were brought together last year in a breeding sanctuary set up in Way Kambas national park in Lampung, South Sumatra province, two years after Andalas was brought from the United States to participate in the programme.
"At the beginning, we were quite pessimistic as Andalas was aggressive and unfriendly towards the female rhinos," Ramono said.
"He chased and fought Ratu or the other females and suffered quite serious wounds that needed at least a month to heal.
"But suddenly on November 16, Andalas softened his attitude towards Ratu and he tried to mate with her for the first time, but he didn't do it properly."
The pair finally got it right on their fourth attempt on January 13, when Ratu conceived, he said.
Poaching is one of the biggest killers of Sumatran rhinos, whose numbers have dropped more than 50 percent over the last 15 years. Their horns are reputed to have medicinal properties.
Explore further: New research uncovers brain circuit in fruit fly that detects anti-aphrodisiac