Scientists at the conservation consortium BioRescue cited risk factors and safety reasons and said that they would stop harvesting 32-year-old Najin’s eggs. “Weighing up risks and opportunities for the individuals and the entire species rendered this decision without an alternative,” BioRescue said in a statement on Thursday.
This leaves Najin’s daughter Fatu — the other northern white rhino on the planet — as the only donor and lone hope to save the species from extinction.
The last male of the species, Sudan, died in 2019 at the Ol Pejeta Conservancy in Kenya, where Najin and Fatu live under high security. Before his death, Sudan’s sperms were collected and have been used to fertilise eggs.
Since 2019, the international consortium has been collecting eggs from Najin and Fatu for a reproduction programme that has never before tried in rhinos.
The procedure involves a team of international vets extracting the rhino’s eggs in a two-hour, high risk procedure carried out under anaesthesia. The eggs are then sent to an Italian lab for fertilisation, in which sperm from two different deceased males are used.
The techniques have taken years of research and development by scientists. So far, 12 embryos have been created, after three were added in July.
BioRescue scientists said the decision-making process to retire Najin was “exceptionally difficult” as they had to look both from the perspective of conservation and ethical rights of an individual animal.
“Retiring one individual from a conservation programme because of animal welfare considerations is usually not a question to think about for long. But when one individual is 50 per cent of your population, you consider this decision several times because it has significant impact on the prospects of the conservation programme,” Dr Frank Göritz and Dr Stephen Ngulu said.
Najin’s recent ultrasound examinations have revealed multiple small, benign tumours in her cervix and uterus as well as a cyst on her left ovary.
But this is not the end of the line for Najin.
She will now play a valuable role as an ambassador for the conservation of her kind. Her tissue samples will be used for stem cell research in an effort to transfer her social knowledge and behaviour to her offspring.
Neither Najin nor Fatu were capable of carrying a calf to term, therefore surrogate mothers for the embryo will be selected from the southern white rhinos population.
Najin was born in a zoo in the Czech Republic in 1989 but moved to Ol Pejeta Conservancy in Kenya in 2009, where she lives under protection from poachers.
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