In a fortunate turn of events, scientists have a fighting chance to save the subspecies.
With only two remaining northern white rhinos, a mother-daughter duo, scientists have intervened with assisted methods of reproduction. The subspecies was declared extinct in the wild in 2008, following the effects of civil war, habitat loss, and aggressive poaching. The last male of the subspecies, beloved Sudan, was humanly euthanised in 2018 at 45, after months of poor health. Leaving behind only a daughter, Najin, and a granddaughter, Fatu, his death is viewed as a cruel symbol of human disregard for nature.
In 2012, Dr Thomas Hildebrandt, an expert in wildlife reproduction, claimed that there was no hope for the northern white rhino. However, recent efforts have given scientists a fighting chance to bring the subspecies back from the void. The pandemic posed challenges, as with disrupted travel and a diversion in science funding, scientists questioned whether or not it was feasible to harvest egg cells from Najin and Fatu and transport the cells from Kenya to a laboratory in Italy. However, the exciting prospect of successfully reproducing outweighed the complexity and cost, and the egg cells made it to Cremona, Italy.
The eggs were matured and combined with frozen sperm from Suni, a deceased rhino bull of the same subspecies whose sperm was collected at a young age and considered healthier than that collected from aged Sudan. Two of Fatu’s eight fertilised eggs were deemed viable and were cryofrozen on Christmas Eve. In a fortunate turn of events, Hildebrandt told The Guardian that he now hopes to “have a calf on the ground in two or three years”.
Unfortunately, Najin is expected to decline as a result of age and a large abdominal tumour, which is pressing against her left ovary, and it was discovered in 2014 that Fatu is not able to bring a calf to term. Consequently, the plan is to plant Fatu and Suni’s embryos into a southern white rhino, a similar rhino derived from the northern white rhino approximately one million years ago. A sterilised southern rhino bull will accompany the cow to help scientists identify when she is in heat. In the meantime, the embryos are being stored in a tank of liquid nitrogen kept at -196C°, with a backup generator for additional security. Once a calf is born, it is vital that it spends time with Najin and Fatu, comments Hildebrandt: “A southern white rhino can provide a northern white rhino milk, but not species-specific knowledge”.
As the frozen embryos allow for the creation of more lifelines, scientists hope to develop more radical methods of saving the subspecies. This could include manufacturing sperm and eggs by changing skin cells to stem cells, a method Nobel Prize-winning scientist Shinya Yamanaka used on mice. Apparently, enough skin cells exist to create a population that would be raised by surrogates and protected in sanctuaries for 20 or 30 years, until northern white rhinos are able to live wildly in the open plains of Kenya once more.