Najin and Fatu had two horns each—one large at the very front of the snout, and a smaller one behind it. But Fatu’s had been lightly trimmed, blunted, to prevent her from jabbing Najin, who is too elderly now to keep up with Fatu’s play. With two armed guards always by their side, the rhinos looked both inviolate and fragile.

But there is more to the lives of these two rhinos than meets the tourists’ eyes. Behind the scenes, veterinarians, cell biologists, and entrepreneurs are rushing to avert their imminent extinction through gene editing and in vitro fertilization. They believe it is still possible to restore the population of northern white rhinos to the African landscape by using surrogates of a closely related species (the southern white rhinoceroses) impregnated with lab-generated embryos from Fatu.

A partner in the rhino project is Colossal Biosciences, with a valuation of $10 billion, which made headlines this spring with its claim to have “resurrected” dire wolves, a species of wolf that went extinct some 10,000 years ago (and was the model for the wolves in Game of Thrones). The company sired three wolf pups from the DNA of ancient dire wolf fossils and modern gray wolves. Embryos with the edited wolf DNA were implanted in dogs, mutts that are a mix of hounds. The company asserted it was the first time an extinct species has been revived by science, even though it’s not an exact clone of the ancient dire wolves.

The ambitious scientists aim for a similar approach with the northern white rhino. As with the dire wolf, the rhino experiment is being watched by skeptics. They question whether genetically engineering a northern white rhino is more of an exercise in technological hubris than genuine conservation. One thing is certain: No two rhinos in the name of conservation have been put through more of an ordeal than Najin and Fatu.