Sudan was at the front of my mind for much of my life. He had a different character from other rhinos – he was so very gentle – and he was like a member of my family.

Sudan was born in the wild in Sudan in 1973, captured when he was two and taken to Dvůr Králové zoo in what is now the Czech Republic. The zoo was the only place to breed northern white rhinos successfully in captivity, and Sudan fathered a daughter, Najin. In 2000, Najin had a daughter, Fatu.

Together with Suni, another male northern white rhino, this family was returned to Africa in 2009. I have been among the team caring for them at Ol Pejeta Conservancy since.

When they came home, the rhinos were so excited. They had been in small pens and now they roamed a 700-acre enclosure, under 24-hour guard. They shared their enclosure with southern white rhinos, a subspecies that still survives in reasonable numbers in the wild. In 2014, Suni died, leaving Sudan as the last male northern white rhino. Even as he aged, Sudan showed plenty of interest in mating with female southern white rhinos. A male rhino has to fight a female first and win that fight before he is allowed to mate. Unfortunately Sudan was overpowered by the females; we had to send him away for his own safety.

If he needed treatment, we didn’t have to sedate him, we just stroked his ears

As Sudan, Najin and Fatu were brought up in a zoo, they knew their names. Rhinos have a good sense of hearing and smell, and they would come towards us when we called. Caress his ears, and Sudan relaxed. If he needed medical attention, we didn’t have to sedate him; we could just stroke the tips of his ears.

While rhinos can live to 60 in captivity, their life expectancy in the wild is in their 40s. Unfortunately Sudan developed an infection in his hind leg and then suffered from sores. He received medication, but by the end he was struggling to get up and wasn’t able to walk outside. He was in a lot of pain. Eventually, the vets had to put him to sleep. He was 45.

We really cried, all the keepers. We held a memorial service for him, which helped. He was a great ambassador for all rhinos, not just his own kind.

I’m still working hard to ensure the two remaining northern white rhinos are content and in good condition for the rest of their lives. They continue to help raise awareness of rhino conservation. If there was no poaching, there would still be good wild populations of northern white rhinos. We are trying to tell everyone that rhino horn does not possess any medicinal value.

This may not be the end of Sudan’s story. Semen was collected from him, and from other captive males, before they died. Scientists now plan to harvest eggs from our two remaining females, create more than one embryo and implant them in surrogate female southern white rhinos. In Berlin, scientists have managed to create an embryo using northern white rhino semen and southern white rhino eggs. Using IVF to try to save rhinos has never been done before. I keep my fingers crossed. I still hope we can save these magnificent creatures.

As told to Patrick Barkham

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