Can We Still Save the Northern White Rhino?

Deep in the African savanna of Kenya, in the Ol Pejeta Conservancy wildlife reserve, live the last known representatives of their subspecies: 24-year-old Fatu and her 35-year-old mother Najin. The northern white rhinoceros (Ceratotherium simum cottoni), a subspecies, stands on the brink of final extinction. Yet international research teams are doing everything they can to make a rescue of these animals possible using state-of-the-art biotechnology.

The story of Fatu and Najin has been shaped by decades of poaching and the destruction of their habitat, which pushed the population to the brink of extinction. Since the death of the last known male, Sudan, in 2018, the northern white rhino has been considered functionally extinct—natural reproduction is no longer possible. Thanks to modern reproductive technologies, however, new possibilities are opening up for the conservation of the subspecies. According to a report by News24, scientists have already developed 36 embryos that are being prepared for implantation in a surrogate mother.

The decline of the northern white rhino

The northern white rhino was once widespread across Central and East Africa, from Uganda through Chad to Sudan. Archaeological finds show that it still occurred in the Nile Valley and even in Morocco in antiquity. But decades of poaching and the ongoing destruction of its habitat led to a dramatic decline in the population. In the 1970s, the population fell to fewer than 40 individuals in Garamba National Park (Democratic Republic of the Congo)—a critical low point.

Although conservation measures led to a slight recovery in the short term, this development was undone by the region’s instability caused by civil war. Illegal poaching by paramilitary groups from Sudan, in particular, caused the population to decline rapidly once again.

Surveys in 2008 found no evidence of any remaining specimens living in the wild. The northern white rhino was therefore officially classified as extinct in the wild in 2009. At that time, only eight specimens remained in human care—six at Dvůr Králové Zoo (Czech Republic) and two at the San Diego Zoo Safari Park (USA). Because the rhinos hardly reproduced in captivity, a final rescue measure was chosen: in 2009, four animals were moved to the Ol Pejeta reserve in Kenya in the hope that a more natural environment would encourage reproduction.

Among the relocated rhinos was Sudan, the last known male individual of the subspecies. Until his death in 2018, he was guarded around the clock by armed rangers. Today, Najin and Fatu are the only two living representatives of this subspecies.

A race against time

Because both Najin and Fatu are unable to carry a pregnancy due to uterine problems, natural reproduction is impossible. Fatu, however, is the last female rhino of her kind that still produces viable egg cells, making her the key figure for in vitro fertilization (IVF).

The egg cells collected from Fatu are transported to Europe, where they are fertilized in the laboratory with cryopreserved sperm from deceased northern white rhinos. Estimates suggest that further collections could yield about ten additional egg cells before Fatu’s ovarian functions decline. By now, 36 fertilized egg cells—or embryos—have been developed and are ready for implantation. Since Fatu cannot carry a pregnancy herself, scientists are relying on a closely related subspecies – the southern white rhino (Ceratotherium simum simum)—as a surrogate mother.

The southern white rhino was already considered extinct at the end of the 19th century until a small population was rediscovered in South Africa. Targeted conservation measures allowed the population to recover and grow to more than 20,000 animals by 2012. But increasing poaching, especially in South Africa, led to another dramatic decline—by 2021, the number had fallen to about 15,940 individuals. Despite these losses, the southern white rhino remains by far the most common rhino subspecies worldwide and occurs not only in South Africa but also in Namibia, Botswana, Zimbabwe, Uganda, Eswatini and Mozambique.

Breakthrough: first successful embryo transfer

A major advance was achieved by the species conservation consortium BioRescue: in 2023, an embryo was successfully implanted in a surrogate mother for the first time, a southern white rhino. Although the first attempt failed because of a bacterial infection in the surrogate mother, the fundamental feasibility of the method was demonstrated. This paves the way for the transfer of a northern white rhino embryo to a surrogate mother.

This progress is significant not only for the northern white rhino—the technique could also help save other highly threatened species such as the Sumatran rhino, whose population in the wild is estimated at about 40 individuals. The subspecies northern Sumatran rhino is already extinct.

Modern Technologies as the Key to Survival

In addition to IVF, researchers are using innovative stem cell technologies. In collaboration with Japanese scientists, they are working to generate new egg cells and sperm from stem cells. If this succeeds, the genetic material of deceased rhinos could be used to restore a more genetically diverse population.

A research team at the University of Oxford is also developing an alternative method: it is investigating whether immature egg cells can be obtained from the ovaries of deceased rhinos and matured in the laboratory. This method could contribute to the long-term conservation of the species even after the deaths of Fatu and Najin.

Ethical Questions and Future Prospects

The probability of success for individual IVF attempts remains uncertain. Previous experience with the southern white rhino surrogate mother shows that several attempts may be necessary. Given the long gestation period of up to 18 months and numerous potential complications, the project remains subject to major uncertainties. Another critical issue is the low genetic diversity. Scientists warn that an overly narrow gene pool could impair the species’ long-term chances of survival.

The coming years will show whether the techniques being used can not only save the northern white rhino but also become critically important for protecting other threatened species.