An international team of zoologists and reproduction researchers is on the way to producing a hybrid rhino to preserve the genes of the northern white rhino, after it became functionally extinct earlier this year.
This is contentious research in the conservation community, with some celebrating the development and others questioning the point of such an endeavour.
The research comes closer than ever before to resurrecting the genes of a large extinct or endangered mammal using artificial reproduction techniques (ART).
Headed by professor Thomas B. Hildebrandt from the Leibniz Institute for Zoo and Wildlife Research, the study aimed to preserve the genes of the northern white rhino by creating a hybrid embryo with a southern white rhino using in vitro fertilisation (IVF), one of the most successful forms of ART.
While the embryos have not yet been implanted into a surrogate southern white rhino mum, the study has succeeded for the first time in developing blastocysts (a collection of differentiated cells from a fertilised egg).
The authors of the Nature article are confident that producing a pure white northern rhino in the future could be possible (they are planning on harvesting eggs from two northern white rhino females, the last of their kind on the planet).
Hildebrandt said that the researchers now need to act quickly and produce a pure northern white rhino that can be raised by the last two remaining females, Fatu and Najin.
"That is really a motivating aspect, to succeed as soon as possible so that the calf we produce can grow up with Fatu and Najin."
In March the last male northern white rhinoceros died in captivity, leaving the subspecies functionally extinct.
Sudan, who lived in Kenya's Ol Pejeta Conservancy was euthanised after a long battle with age-related health issues, his death leaving only Najin and Fatu.
The northern white rhino range was originally a broad swathe of central Africa but by the late 20th century the population was reduced to a small number in Garamba National Park in the Democratic Republic of the Congo.
Throughout the 1970s and 80s, poachers harvesting rhino horns for traditional Chinese medicine reduced the northern white rhino population from 500 to 15.
The rhinos were victims of the violence throughout the Congo War as militia groups funded their operations with the horn trade. They were declared extinct in the wild in 2008.
In 2009 four of the last northern white rhinos were transferred from Dvur Kralove Zoo in the Czech Republic to Ol Pejeta in Kenya in the hopes that it would improve breeding conditions for the animals.
However, all of the animals were old and Sudan was found to have a low sperm count several years before his death, this making breeding near impossible.
The demise of the northern white rhino was a blow to Cathy Dean, CEO of the Save the Rhino International, an organisation that had been involved in supporting the wild population of the rhinos in Garamba National Park since its inception in 1994.
Save the Rhino International made the decision to pull funding in support of the northern white rhino in 2008 after the rhinos were found to be extinct in the wild.
"It was pretty heartbreaking to essentially write-off our involvement with the northern white rhinos at that point," Dean told BuzzFeed News.
Dean is a proponent of on-the-ground conservation and since the wild extinction of the northern white, her organisation has turned towards protecting remaining viable populations of wild rhinos.
"For us, that means focusing on the black [rhino], the Sumatran, and the Javan; we've still got animals to work with."
Dean is also concerned about what will happen to the hybrid rhinos if they are successfully bred from Hildebrandt's study.
"I think the big unanswered question is, if and when they succeed, what do you do with those animals? Where do they live? Do they live in zoos in the [United] States?"
The researchers say they are hoping to have northern white rhino offspring in zoos on three continents within five to 10 years.
Dean is not alone in her scepticism about the use of ART to save the genes of the northern white rhino.
Dr Jason Gilchrist, an ecologist from Edinburgh Napier University, told BuzzFeed News the advances in ART are impressive, but that he maintains a philosophical opposition to breeding a hybrid northern white rhino population only to be displayed in zoos.
"I would like wild animals to be in the wild and I'm slightly concerned that what we're doing here – if all this works and with all the things that still have left to be determined – what we're doing is creating a population that would then be held in captivity."
While Gilchrist acknowledges the potential value of applying ART in conservation, he is unsure of its application to the northern white rhino.
"The crux of this is, 'What is the point?' The point ultimately of this, to be useful, to be valuable, it has to lead to there being a sustainable population of northern white rhinos in the wild."
The value of the northern white rhino's genes is debated amongst conservationists. The subspecies split with the southern white rhino approximately 80,000 years ago and shows a genetic difference of 0.1%. For reference, the genetic difference between the Indian and African elephant subspecies is 5%.
The genetic difference is found mostly in olfactory (smelling) genes and the authors of the Nature article believe this is enough divergence to support the proliferation of northern white rhino genes.
Gilchrist disagrees and believes that the southern white rhino could fill the ecological gap left by the extinction.
"I suspect that the subspecies weren't fundamentally different enough for the southern white rhino not to be successful and effective at sustaining a population in the range of the northern white rhino."
Hildebrandt does not believe that is a viable solution.
"It [the northern white rhino] looks different, has much bigger feet, it's much larger, has hair on the ear, they're different creatures, so we could not send southern white rhinos to central Africa."
For Dean and Save the Rhino International, the greatest frustration is that funding towards these ART programs may be hived off from frontline conservation work.
"Looking at the size of some of the large grants that go to the academic side or the more scientific side, [and I'm] thinking 'My rangers haven't even got a pair of boots, they haven't got socks'."
A article that accompanies Hildebrandt's work in Nature disputes this funding concern: "Funds available for high-tech scientific approaches like ART often are not transferable to 'boots on the ground' conservation measures".
Gilchrist believes it is less a matter of funding and more a matter of attention. "I do think that in terms of perception and attention ... in a sense we're distracting the issue away from what I see as an ecologist as the most important point of conservation, which is trying to deal with the issues that cause the endangerment on the ground."
However, for Hildebrandt, it is about trying to reverse human wrongdoing.
"The northern white rhino didn't fail in evolution, it failed because it is not bullet-proof."