The poaching crisis of the 1970s and 80s, fuelled by demand for rhino horn in traditional Chinese medicine in Asia and dagger handles in Yemen, wiped out the northern white rhino populations in Uganda, Central African Republic, Sudan and Chad. The last remaining wild population made up of 20-30 rhinos in Garamba National Park in the Democratic Republic of Congo succumbed during fighting in the region during the 1990s and early 2000s. By 2008, the northern white rhino was considered by most experts to be extinct in the wild.

In 2009, the last four fertile northern white rhinos – two males and two females – were moved to Ol Pejeta from Dvůr Králové Zoo in the Czech Republic, with support from Fauna & Flora International. It was hoped that the climate and rich grasslands of the conservancy, similar to the native habitat of this subspecies, would provide them with more favourable breeding conditions.

On arrival at Ol Pejeta, the last four rhinos were placed under 24-hour armed surveillance, and fed on a supplemented diet. However, despite the fact that they were seen mating, there were no successful pregnancies.

In early 2014, plans to introduce a male southern white rhino to the last two female northern whites got underway in the hope that, if breeding were successful, the hybrid offspring would at least conserve some of the northern white rhino’s genes. Again, this proved unsuccessful. Tests later revealed that neither of the females was capable of natural reproduction, and only one was fertile enough to conceive artificially. The death of the other northern white male, Suni, of natural causes in October 2014, further emphasised the need to urgently come up with alternative solutions.

There is no denying that the loss of Sudan is a crushing blow – not only for those who cared for him, but for rhino conservation as a whole. However, all hope is not lost.

Although rhinos around the world are facing unprecedented threat from poaching for their horn, experience shows that – when properly protected – numbers can recover.

One such success story is at Ol Pejeta itself, which (aside from its resident northern white rhinos) is East Africa’s largest sanctuary for black rhinos – a critically endangered species with only around 5,000 individuals remaining in the wild. This critical and growing population is the result of many years of dedicated conservation work and effective protection.

“We must learn our lesson from this tragedy, and take urgent action to ensure that never again do we allow numbers to fall so perilously low,” says Mark Rose, Chief Executive at Fauna & Flora International. “We can save the rhino, but it’s a long hard road ahead.”