The world’s last male northern white rhino died on Monday at the Ol Pejeta Conservancy in Kenya. With the death of the 45-year-old Sudan, the Earth’s entire northern white rhino population is now down to two — Sudan’s daughter, Najin, and his granddaughter, Fatu. Both females also live at the Ol Pejeta Conservancy.
The death of Sudan resonates in a major way in San Diego. The San Diego Zoo Safari Park was home to Nola, a female northern white rhino who died in November 2015 at age 41, leaving Sudan, Najin and Fatu to represent the subspecies. The Safari Park’s other northern white rhino, a male named Angalifu, died in December 2014 at age 44.
“Our hearts really go out to the people at Ol Pejeta who have known and cared for (Sudan) for so many years,” said Dr. Barbara Durrant, San Diego Zoo Global’s Henshaw endowed director of reproductive sciences at the San Diego Zoo Institute for Conservation Research.
“I never met him, but I have met many people who said he was a mild and good-natured animal who was just enjoying life.”
Sudan was euthanized after a severe leg infection had caused his health to deteriorate. But like Nola and Angalifu, he lives on as part of the Frozen Zoo.
The Frozen Zoo — which is housed inside the San Diego Zoo Institute for Conservation Research just up the road from the Safari Park outside Escondido — is a collection of more than 10,000 living cell cultures, sperm and other genetic materials representing nearly 1,000 species and subspecies. The Frozen Zoo materials from Sudan, Nola and Angalifu are part of a global effort to use genetics and advanced reproductive technologies to save the northern white rhino from total extinction brought about by war and poaching.
The Frozen Zoo contains viable cell cultures from 12 northern white rhinos. It does not include any northern white rhino eggs, but Durrant and her colleagues hope to one day extract eggs from Najin and Fatu or to create eggs from pluripotent stem cells. The long-range plan is to fertilize the eggs in vitro with banked sperm, and then have a female southern white rhino from the Safari Park’s Nikita Kahn Rhino Rescue Center act as a surrogate and carry a northern white embryo to term.
That phase could be 10 to 15 years away, and it would be just the beginning.
“For us, it is heartbreaking to see yet another species being lost,” Durrant said. “Our end goal, and what we keep in our minds at all times, is a self-sustaining herd of northern white rhinos living back in their habitat. That is what we are aiming for.”