Conservationists in Kenya have been extracting oocytes from the last two female northern white rhinos on the planet- in an attempt to save the species from extinction using IVF.

Neither female is able to carry a pregnancy, and now the older rhino, aged nearly 33, has become too old for successful extraction, leaving all hopes pinned on the younger 22-year-old.

Still, scientists are getting closer to being able to attempt IVF after the successful production of fourteen embryos.

Najin and Fatu – the last two northern white rhinos on the planet – both female, both incapable of carrying a pregnancy. The last male died in 2018.

Conservationists at the Ol Pejeta Conservancy in Kenya and their colleagues around the world are in a race against time to create a successful pregnancy using eggs harvested from Najin and Fatu and sperm collected from male northern white rhinos before they diedใ

In February 2022, Kenya Wildlife Service reported that two new northern white rhino embryos had been created.
This is after procedures that were carried out in October 2021 and February 2022. The embryos are currently preserved in liquid nitrogen and are expected to be transferred to surrogate southern female rhinos in the near future.

So far fourteen embryos have been created according to Samuel Mutisya, Head of Conservation at Ol Pejeta Conservancy. “A lot of work has gone into preparing the necessary equipment and procedures for oocyte collection or the collection of eggs from the two females that exist that are here in Ol Pejeta, Najin and Fatu and that has taken place severally (several times) and we have managed to successfully create at least 14 embryos that are now preserved in liquid nitrogen for the purposes of implantation on surrogate females, southern white rhino surrogate females here at Ol Pejeta,” said Mutisya.

Other partners involved in the project are BioRescue, a group made from scientists from Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Germany, Safari Park DvůrKrálové in the Czech Republic, the Kenya Wildlife Service, and Avante lab, Padua University, Italy.

Currently, scientists are experimenting with southern white rhino embryos with the aim of perfecting the implantation process.

“The procedures for implantation have not been so successful and therefore there is a need to perfect that before you use the pure northern white rhino embryo,” explains Mutisya.

“So we have been trying out using the southern white rhino embryos to see to it that the procedure is perfected before you use the very precious northern white rhino materials or embryo in the procedure, but we are optimistic that overtime this is a hurdle that we will jump or cross.”

Although two female northern whites remain, hopes are pinned on the younger rhino named Fatu who was born in 2000. Her mother, Najin now almost 33, is becoming too old to produce healthy oocytes.

“We have done a bit of oocyte collection in Najin for example and none has developed into a viable embryo,” explains Mutisya.

“She also has some inherent conditions that make it very hard to stimulate her for the purpose of collecting oocytes, so in fact as we speak Najin has been retired on those grounds. So we are left with her daughter Fatu and that has been quite successful in terms of the number of oocytes collected from her and the number of oocytes that have developed into viable embryos. So hope really hinges on Fatu as a source of oocytes or eggs that will be used for the purposes of creating embryos.”

Decades of poaching have taken a heavy toll on all rhino species. The animals are killed for their horns, which have long been used as carving material and prized in traditional Chinese medicine for their supposed healing properties.

Southern white rhinos and the black rhino are also prey for poachers, the former being listed as Near Threatened on the IUCN (International Union for Conservation of Nature) Red List of Threatened Species, with the latter Critically Endangered.

The last male northern white rhino was a 45-year-old named Sudan, who gained fame in 2017 when he was listed as “The Most Eligible Bachelor in the World” on the Tinder dating app as part of a fundraising effort. He was euthanized in 2018 because of age-related conditions.

Mutisya describes the battle to save the northern white rhino as “fire fighting” and raises concerns that if lessons are not learnt on how to look after precious natural resources, the same errors – poaching, habitat loss -coupled with an increasing threat of climate change will claim other species too.

For now, he and his team remain optimistic, pegging their hopes on science to save the northern white.

by Associate Press