"Taking into account 16 months (of) pregnancy, we have a little more than a year to have a successful implantation.".
The team's work, using a recently-patented, two-metre (6.6-foot) egg extraction device, resulted in the first-ever test tube-produced rhino embryos.
Now frozen, these "have a very high chance to establish a pregnancy once implanted into a surrogate mother," said Hildebrandt.
The hybrid embryos were created with frozen sperm from dead NWR males and the eggs of southern white rhino (SWR) females, of which there are thousands left on Earth.
The team now hopes to use the technique to collect eggs from the last two northern white rhinos -- Najin and Fatu, the daughter and granddaughter of Sudan.
By fertilising these with northern white rhino sperm and implanting the resulting embryos in surrogate southern white rhino females, the team intends to create a new, fledgling NWR population.
"Achieving the latter requires navigating an untrodden path fraught with obstacles, and it remains unlikely that a viable population of northern white rhinos will be restored.". »