The northern white rhinoceros needs a miracle.
Despite decades of Hail-Mary attempts from captive breeding programs, only two northern white rhinos are still alive today: a mother-daughter pair in Kenya named Najin and Fatu. The last male, named Sudan, died this past March. With his death, the survival of the subspecies, which has been driven to near-extinction by poaching in Central Africa, seemed bleak.
Yesterday, however, an international group of multidisciplinary scientists announced some much-needed good news for the northern white rhino. In a paper published in Nature Communications, the researchers reported the first step in a long road to resurrecting the subspecies: the creation of the first ever in-vitro rhino embryos.
The four embryos were made from frozen northern white rhino sperm and eggs taken from the closely related southern white rhino. The hope is that these hybrid embryos will be implanted into surrogate southern white rhino females in the coming months.
But there’s still a lot of work to be done before we see a newborn white rhino. To date, while common in humans and livestock, in vitro fertilization has never succeeded in a rhino. Here’s Steph Yin of the New York Times on what happens if the surrogacy succeeds, and why it may not be a fail-safe approach:
If that succeeds, the researchers will appeal to Kenyan authorities to let them harvest eggs from Najin and Fatu, then fertilize the females’ eggs with stored northern white rhino sperm. The team hopes to see the first purebred northern white rhino born to a surrogate through this method in three years, Dr. Hildebrandt said.
One major drawback to this tactic is that the genetic pool from just two northern white cows and four bulls is extremely limited, and would likely lead to severe inbreeding.
To get some fresh blood into the white rhino’s gene pool, the team of researchers is also looking into another high-tech reproductive method. Using skin samples taken from a dozen rhinos at the San Diego Zoo, the researchers have generated stem cells, called induced pluripotent stem cells (iPS) that could potentially be turned into eggs and sperm. This technology is “a decade or so” from being developed, the researchers reported.
Not everyone agrees that having the technology to bring back the northern white rhino means we should do it. Critics question whether the efforts shift focus from on-the-ground conservation efforts or from other animals that have better chances for survival in the wild.
But if the efforts are eventually successful, they could help efforts to restore populations of other large mammals that have fallen prey to human-induced endangerment, like the African elephant and polar bear.