The white rhino is the second largest land mammal, and as a species, it is the only rhinoceros species that isn’t considered endangered or critically endangered by IUCN. That said, only one subspecies of white rhino has relatively healthy numbers. That would be the subspecies known as the southern white rhinoceros, which has an estimated population of over 17,000 individuals. Its range is in southern Africa.
The other subspecies is not so well-off. Indeed, it might be safe to say that this subspecies is functionally extinct. The other subspecies is the northern white rhinoceros, which has (or had) a range in Central and East Africa.
The best estimate of the population of the northern white rhinoceros is 8 in captivity and 4 in the wild. Now, take this with a caveat, because those four wild white rhinos haven’t been seen since 2006. Those four were living in Garamba National Park in the Democratic Park of Congo, which is not the most stable country in the world. It is now suspected and largely accepted that there are no wild northern white rhinos left.
As for the surviving eight captive northern white rhinos, things are not that good at all. The San Diego Wild Animal Park has two northern whites, and the Dvůr Králové Zoo in the Czech Republic has the remaining six. The Dvůr Králové Zoo also has a crossbred rhino, but such crossbred animals cannot be part of a breeding program.
The San Diego population is not breeding. Their original population of three consisted of a fertile male, an infertile female, and a female that was not behaviorally receptive to the male’s advances. So this population is not breeding at all. However, the Czech population is fertile.
Now, I don’t know if you’ve noticed this, but those two populations aren’t very close to each other. That means that transporting them to breed with each other is a major hassle and very costly. AI attempts are being proposed.
But I don’t think you’re going to save this subspecies with just a few breeding animals– unless it ever becomes acceptable to breed them with the southern subspecies. Now, such a suggestion is heresy in animal conservation programs.
The animal that is preserved must be the exact subspecies. Hybrids don’t normally count. However, sometimes, it does. Most American bison on the prairies today have domestic cattle ancestry– not much.
And I think that if an exception can be made for these bison, which have the blood of an entirely different species in their veins, then I think we can make an exception for hybrids between the two subspecies of white rhino.
Because that’s really the only hope the northern white rhino has.