Najin and Fatu seem unaware they're the last of their kind. Scientists hope they can add just one more per year.
Zimbabwe's Bubye Valley Conservancy is closely guarded.
Johannesburg breeder John Hume says that making rhino horn more easily available will deter poachers from killing the rare animals.
Should we be saving the rhinos or the poachers driving them to extinction? The answer is not as easy as you might think.
An international ban on trading rhino horn remains in place.
But experts worry legal schemes can't overcome poaching and illegal profits.
International trade in rhino horn is prohibited, but it can sell for $60,000 on the black market.
The rhino was killed by poachers less than 10 hours before Prince William and Kate visited Kaziranga national park.