Cincinnati Zoo scientists are turning to incest to save an endangered rhino species from extinction. The team plans to have their lone female Sumatran rhino mate with her younger brother.

Scientists estimate there are around 100 Sumatran rhinos left in the world. Since the mid-1980s, the species population has plummeted by up to 90 percent. Conservationists blame poachers who hunt them for their horns, the Associated Press reports.

“We are down to the last male and female Sumatran rhino on the continent, and I am not willing to sit idle and watch the last of a species go extinct,” Dr. Terri Roth, vice president of conservation and science and director of CREW at the Cincinnati Zoo, told NBC News.

Eight-year-old Suci, the lone female in question, and her brother, Harapan, are the two remaining Sumatran rhinos left in North America. Incest is not ideal, but it may be one of the species’ best chances for survival, Roth said in a statement.

“No one wants to breed siblings -- it is something we strive to avoid -- but when a species drops below 100 individuals, producing more offspring as quickly as possible trumps concerns about genetic diversity,” he said.

Harapan, a 6-year-old male Sumatran rhino, was born at the Cincinnati Zoo in 2007. Now at the Los Angeles Zoo, he will soon return to Cincinnati to mate with his biological sister, Suci. The two will be kept in separate enclosures until the time is right to reintroduce the animals. If they start to show aggressive behavior, scientists say they will try to separate them by using distractions like bananas.

"They're definitely difficult to breed, because they're so solitary," Roth told AP. "You can't just house them together. So the only time you can get a successful breeding is if you just put them together when the female is going to be receptive."

Until then, scientists are monitoring Harapan’s testosterone levels and ultrasounds to see when Suci is ovulating. If the mating is successful, a baby rhino will be born in 16 months, AP reports.

The Sumatran rhinoceros, a forest dwelling species native to parts of Malaysia, Indonesia and Myanmar, is believed to be the most endangered large mammal in the world. According to Roth, the species maintains healthy forests by eating small saplings and brush, which gives more room for trees to grow. This plays a role in absorbing carbon dioxide in the atmosphere that can reduce the impact of climate change.  

“This is why the Midwestern American farmer who is tired of droughts and tornadoes and who is worried about how next year's crops will do and how the bills will get paid should care about saving the Sumatran rhino,” Roth said.

This isn’t the first time the Cinncinati Zoo has made strides to save the Sumatra rhino population. In 2001, Andalas became the first Sumatran rhino to be born in captivity after 112 years. He was later moved to a sanctuary in Indonesia where he successfully mated with a wild rhino last year.

But Indonesia continues to struggle with the dwindling rhino population. Bukit Barisan Selatan National Park in Sumatra is estimated to have the largest single population of Sumatran rhinos, according to the World Wildlife Foundation. The park continues to lose forest cover from illegal settlers who use the land to produce coffee and rice.

Roth argues that there has been “resistance” by the Indonesian government to capture rhinos to prevent inbreeding the endangered species.  

“There needs to be serious and immediate action that addresses excessive deforestation and poaching that is wiping out so many species in Southeast Asia, especially rhinos and tigers,” Roth said. “First and foremost, we have to secure the few surviving wild populations. However, the captive breeding program could also benefit if governments acknowledge the crisis and act accordingly.”