The team in August, successfully harvested 10 eggs - five from Najin and five from Fatu, the two females who live in Ol Pejeta Conservancy — a procedure that has never been attempted in northern white rhinos before.
Only two, Najin and Fatu remain, both on Ol Pejeta Conservancy. They are the last two northern white rhinos in the world, both of them female.
This was achieved through Intra Cytoplasm Sperm Injection with frozen sperm from two different northern white rhino bulls, Suni and Saut, last month.
This is the next critical step in hopefully creating viable embryos that can be frozen and then later on transferred to southern white rhino surrogate mothers.
“We were surprised by the high rate of maturation achieved as we do not get such high rate with southern white rhino females in European zoos,” said Cesare Galli of Avantea in Cremona (Italy) who led the fertilisation procedure.
“The semen of Saut was very difficult to work with and to find three live sperms needed for the eggs of Najin we had to thaw two batches of semen. Now the injected oocytes are incubated and we need to wait to see if any viable embryo develop to the stage where it can be cryopreserved for later transfer,” said Cesare Galli of Avantea in Cremona (Italy) who led the fertilisation procedure,” he added.
The international research consortium to save the northern white rhino from extinction is led by Prof. Thomas Hildebrandt from the Leibniz-Institute for Zoo and Wildlife Research (IZW).
Avantea is responsible for maturing the egg cells and creating viable embryos, further key project partners are Dvůr Králové Zoo, Ol Pejeta Conservancy and the Kenya Wildlife Service.
The results of possible embryo development are to be announced around September 10th.
The northern white rhino is a subspecies of white rhino, which used to range over parts of Uganda, Chad, Sudan, the Central African Republic, and the Democratic Republic of the Congo.
Years of widespread poaching and civil war in their home range have devastated northern white rhino populations, and they are now considered to be extinct in the wild.
In March 2018, the world's last standing male northern white rhino, died aged 45.