LONDON (Reuters) – A British zoo is using IVF technology to help the three remaining northern white rhinos procreate and save the species from extinction.

Scientists at Longleat safari park in Warminster, England, extracted nine eggs from three female southern white rhinos in their facility earlier this week.

The eggs will be used by researchers at a clinic in Italy to develop IVF technology that eventually could be used with genetic material from the northern whites.

If scientists are unable to use IVF to create a pure northern white rhino, they have a back-up plan: to create and embryo using eggs from southern whites and sperm from a northern white to create a new hybrid species.

The southern white rhino is a sub-species that shares many of the characteristics of the northern white. While there are only three northern white rhinos left – all in captivity in Kenya – there are over 20,000 southern white rhinos, according to the World Wildlife Fund.

Advanced age and fertility problems have meant that the three remaining northern whites have been unable to breed naturally.