The world’s last two northern white rhinos

There are now only two northern white rhinos left in the world: Najin, a female, was born in captivity in 1989. She is the mother of Fatu. Her mother was Nasima and her father was Sudan. (Source: REUTERS/Thomas Mukoya)

Northern white rhinos, which are actually grey, used to roam freely in several countries in east and central Africa, but their numbers fell sharply. (Source: REUTERS/Thomas Mukoya)

Najin (R) and her daughter Fatu, the last two northern white rhino females, graze near their enclosure at the Ol Pejeta Conservancy in Laikipia National Park, Kenya March 31, 2018. (Source: REUTERS/Thomas Mukoya)

The animals were heavily threatened by widespread poaching for their horns. (Source: REUTERS/Thomas Mukoya)

Children pose for a photograph next to Najin (R) and her daughter Fatu, the last two northern white rhino females, as they graze near their enclosure at the Ol Pejeta Conservancy in Laikipia National Park, Kenya March 31, 2018. (Source: REUTERS/Thomas Mukoya)

A ranger feeds Najin (R) and her daughter Fatu, the last two northern white rhino females, with carrots near their enclosure at the Ol Pejeta Conservancy in Laikipia National Park, Kenya. (Source: REUTERS/Thomas Mukoya)

Researchers have been racing against time to save the world's most endangered mammal. (Source: REUTERS/Thomas Mukoya)

Also known as the square-lipped rhinoceros, white rhinos have a square upper lip with almost no hair. (Source: REUTERS/Thomas Mukoya)

White rhinos have complex social structures. Groups of sometimes 14 rhinos may form, notably females with calves. (Source: REUTERS/Thomas Mukoya)

Conservation efforts to save the last two of this mighty species are regular and ongoing. (Source: REUTERS/Thomas Mukoya)