There are just two northern white rhinos left on Earth, both females and both getting on in years. The subspecies is, in fact, functionally extinct.
Into the breach has stepped BioRescue, a multinational project with a mission to save the northern white rhino through in vitro fertilisation (IVF). Earlier this year, there was much rejoicing when BioRescue's scientists announced an extraordinary milestone: it had accomplished the first-ever rhino pregnancy using IVF. They had implanted a southern white rhino embryo in a surrogate mother named Curra.
And it was successful, until a few months into the pregnancy, when Curra died of an unrelated bacterial infection (a rhino pregnancy is a 16-month affair). The team confirmed a pregnancy of 70 days with a welldeveloped, 6.4 cm-long male embryo. It was the latest step in a years-long effort to save the northern white rhino from extinction.
The breakthrough was the essential ‘proof
