Two new embryos created to save the northern white rhino from extinction

Only two northern white rhinos remain, and both are females, but scientists have created two new embryos to save the species, for a total of five.

When northern white rhinos became extinct in the wild, back in 2008, and then when all the males of the species had died by 2014, it was hard to imagine their survival in the future. But now there’s a chance.

An international consortium of scientists and conservationists working to prevent the extinction of the northern white rhino has announced that, in December 2020, two new northern white rhino embryos were produced through assisted reproduction technologies.

The first three were produced in 2019, totalling five embryos today. This is an incredible achievement – even more so considering the challenges and delays caused by the Covid-19 pandemic.

An international effort to save a species

Najin and Fatu at Ol Pejeta Conservancy in Kenya are the only remaining northern white rhinos in the world – and they are both females. This is why Ol Pejeta has security measures in place to protect the two animals from the constant threat of poaching.

With only two females surviving, it may seem impossible to bring the species back from the brink of extinction, but if the scientists succeed they might create a precedent, a blueprint that may be used to save other species.

In order to avoid the extinction of the northern white rhino, BioRescue – led by Thomas Hildebrandt of the Leibniz Institute for Zoo and Wildlife Research (IZW) – is working to harvest immature egg cells, oocytes, from the two females and artificially inseminates them using frozen sperm from males that are now deceased. The consortium of researchers working with BioRescue includes: Avantea, an Italian lab for advanced technologies in animal reproduction based in the northern city of Cremona, which has led the in vitro fertilization process; the Kenya Wildlife Service; Ol Pejeta Conservancy, as mentioned; and Dvůr Králové Zoo, a safari park in the Czech Republic and one of the best rhino breeders outside of Africa.

In the latest procedure, the oocytes were retrieved from Fatu only. Previously, collecting oocytes from her mother, Najin, was successful, but no embryos were created from her egg cells. The rhino reproduction specialists believe that this might be due to Najin’s health issues. The 31-year-old rhino has a large tumor in her abdomen, which may hamper the functionality of her reproductive organs.

Fatu is undergoing the ovum pick-up procedure. Prof. Dr. Robert Hermesfrom Leibniz-IZW (left), Prof. Dr. Thomas Hildebrandt from Leibniz-IZW (middle) and Dr. Susanne Holtze from Leibniz-IZW (right) © Ami Vitale

In 2014, scientists discovered that Fatu was likely infertile due to cysts and uterine lesions, and elderly Najin also was unfit for birthing: her hind legs are weak and veterinarians believe a pregnancy would be harmful to her. To bypass this issue, the embryos will be implanted in surrogate mothers of the southern white rhino species, of which there are many more specimens – between 17,212 and 18,915 in the wild.

How the northern white rhino became functionally extinct

There are five different rhino species in the world: three in Asia and two in Africa, and two of these have less than 80 animals surviving in the wild. Northern white rhinos, in particular, have been wiped out by poaching and loss of habitat. An average of three rhinos are poached for their horn every day across Africa, according to Save the Rhino, a UK-based (and Europe’s largest) rhino charity. As late as 1960, there were around 2,360 northern white rhinos, says Save the Rhino, but widespread poaching and civil unrest decimated the species, shrinking the population to only 15 by 1984.  After an encouraging increase in numbers by the 90s, the northern white rhino population plummeted once again during the Congolese Civil War because harvesting ivory and rhino horn was one method the rebel and militia groups raised funds for their operations. By 2008 they were extinct in the wild.

What the future looks like for the embryos

“We plan to have a calf on the ground in two to three years,” Hildebrandt told the Guardian.

The two embryos are now stored in liquid nitrogen, along with other three obtained from previous procedures, and are waiting to be transferred into a southern white rhino surrogate mother in the near future. Then, it will be critical for the newborn baby to spend time with Fatu and Najin in order to learn “species-specific knowledge”, as Hildebrandt said.

Conservation as a public health issue

The success of this procedure is deeply tied to the importance of preserving keystone species and ecosystems. It is crucial to save this species because it carries a so-called “umbrella function”: its extinction could cause that of many other animals, insects or plants. Rhinos are browsers and they distribute seeds through their faeces, making them “landscape architects”.

Najin and Fatu at Ol Pejeta Conservancy © Jan Zwillling/IZW BioRescue Northern White Rhino Recovery

“There are other species that could benefit (from these techniques), like the Sumatra rhino, where we haven’t reached the criticality of two individuals yet, but even so, only a couple dozen remain, so now should be the time to collect and conserve genetic material,” Cesare Galli of Avantea said in an interview with LifeGate in 2019, when the first three embryos were produced. Steven Seet head of Science Communication at IZW, echoed this in another interview that same year: “I read a quote from my colleague the other day, he was saying that animals are like textbooks and today…we’re destroying the library of life”.

Never more so than today has the conservation of ecosystems been a public health issue. With the risk of more pandemics to come in the future it is crucial to stop interfering with the ecosystems’ balance.

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