A ranger reaches out towards female northern white rhino Najin, 30, one of the last two northern white rhinos on the planet, in her enclosure at Ol Pejeta Conservancy, Kenya.

Video. Thirty white rhinos flown out in Boeing 747 to resettle in Rwanda

The southern white rhino, one of two subspecies of white rhino, is now considered endangered with about 20,000 individuals remaining, according to the World Wildlife Fund (WWF).