Northern White Rhino's Death at San Diego Zoo Leaves Only 3 of Its Kind in the World

— -- An endangered northern white rhinoceros died Sunday at the San Diego Zoo, leaving only three of its kind in the world.

Nola, a northern white rhino believed to be about 41, had been experiencing health issues lately, San Diego Zoo Global spokeswoman Christina Simmons told ABC News today, which prompted the animal care team to make the “difficult” decision to euthanize her.

The rhino, which was brought to Safari Park in 1989 from the Dvur Kralove Zoo in what is now the Czech Republic, was treated in November for a bacterial infection that created a large abscess in her pelvic region, and was recovering well, Simmons said.

“But, for whatever reason in the last couple of days, her health had started to decline and we were seeing generalized organ failure,” Simmons said.

The animal care staff at the zoo pulled together a group of professionals to evaluate the welfare of the animal, Simmons said, which ultimately led to the decision to euthanize the critically endangered rhino.

The other three northern white rhinos – Najin, Fatu and Sudan, all from Dvur Kralove Zoo as well – are under managed care at Ol Pejeta Conservancy in Kenya, Simmons said. The two females and one male are watched under 24-hour armed security to keep poachers from killing them for their horns, which, Simmons said, poachers believe will “have value in the future.”

She added: “We’re calling it an extinction crisis, there’s only a few left because they’ve been wiped out in the wild because of poaching.”

In a “last-ditch effort” to save the northern white rhino, Simmons said, researchers at the San Diego Zoo have developed technology to possibly implant embryos from the endangered rhino into six southern white rhinos, a species closely related to the northern white rhino, that the zoo welcomed in November.

“Of course, nothing like this has ever been done before, so we don’t know that it will be successful, but it is really our last hope for recovering the species,” Simmons said, adding that this research could help save two other endangered species as well: the Javan rhino and Sumatran rhino.

If the zoo’s efforts are successful, Simmons said, a northern white rhinoceros calf could be born in five to 10 years.