One of the world's last two northern white rhinoceroses has been withdrawn from a breeding program in Kenya to save the species from extinction.

The 32-year-old rhinoceros Najin is the mother of Fatu, who is now the only donor left in the program.

The aim of the breeding program is to implant artificially developed embryos into another more common rhinoceros species in Kenya.

No male northern white rhinoceroses are known to be alive and the two remaining females are unable to carry a calf to full term.

Northern white rhinoceroses (which are actually gray) used to roam freely in several countries in East and Central Africa, until their populations plummeted at the hands of poachers chasing the animals for their horns.

Race against the clock

A Biorescue team led by researchers from the Leibniz Institute for Zoo and Wildlife Research in Germany is racing against time to save the world's most endangered mammal.

Nevertheless, it has now been decided to withdraw Najin from the program as an egg donor.

The team made this decision due to ethical considerations coupled with Najin's advanced age and signs of illness.

The scientists hope to implant embryos created with eggs from females and frozen sperm from deceased males into surrogate mothers.

The team hopes to give birth to its first northern white rhinoceros calf within three years and expand the population over the next two decades.

Keywords: rhinoceroses, breeding program, world, species, extinction, kenya, mother, females, rhinoceros, poachers, najin, team, program., aim, donor