Northern white rhino: How scientists hope to save rare breed from extinction

Northern white rhino: Researchers are hoping that tissue samples taken from a recently deceased white rhino will help keep the species from disappearing.

There are only four northern white rhinoceros left alive in the world after the death of one of the critically endangered animals in a zoo.  

Nabire, a 31-year-old female, passed away, authorities at the Dvůr Králové Zoo in the Czech Republic announced on Monday.

"Her death is a symbol of the catastrophic decline of rhinos due to senseless human greed," zoo director Premysl Rabas said in a statement.

Nabire endured some health issues that made it impossible for her to breed naturally.

Sudan, the only living male of the species, lives in Ol Pejeta Conservancy in Kenya, under 24-hour armed guard. His horn has already been removed to deter poachers, CNN reports.

This leaves the breed with little chance of surviving through natural means as Sudan has little chance of reproduction due to his age. "Sudan is currently old and may not be able to naturally mount and mate with a female," George Paul, a deputy veterinarian at Ol Pejeta Conservancy told CNN.

After Nabire’s death, her potentially healthy ovary was immediately removed and taken to a specialized laboratory in Italy for scientific research and reproduction work. 

Conservationists hope to use her harvested eggs in a form of in vitro fertilization (IVF) to produce a rhino baby with a southern white rhinoceros, the closest living relative to the rare northern whites.

The three remaining northern white rhinoceros females are all incapable of breeding. In 2009, four rhinos were moved from the Dvur Kralove Zoo to Kenya hoping that the natural habitat there would help them breed, but the plan was unsuccessful.  

The Dvur Kralove Zoo is persistent. Staff plans to continue efforts to save the endangered animal.

"It is our moral obligation to try to save them. We are the only ones, perhaps with San Diego Zoo, who have enough collected biological material to do so. We are aware that our chances are slim, but the hopes are still alive," Rabas told CNN.

Northern white rhinos have been on the brink of extinction for years because of poaching and habitat loss. According to Ol Pejeta Conservancy, home to Sudan and two of the remaining female northern whites - Najin and Fatu - there were only a few dozen of the animals living in the Democratic Republic of the Congo in the early 2000s.