Sudan the rhino walking past a hill / Photo by Flickr.com
Endangered animals pose a lot of threat from us - humans, and surprisingly, almost half of some species will soon be extincpoachit by 2050 if we do not act now.
Alarming news had stirred the planet last March. Sudan, a male northern white rhino had died. Well-known as the ‘most endangered mammal in the world’, only two remaining rhinos exist today. Both females, Najin and her daughter Fatu, are living in a sanctuary in Kenya and protected around the clock by armed guards at the Ol Pejeta Conservancy.
The Last of their Kind
Poaching is the primary reason why this rhino is extinct today.
Loss of habitat is the other primary threat to rhinos, and conservationists say that governmental protection of parks and reserves is now essential.
"The proper legislation must be passed, the resources to enforce the regulations must be provided and the law must be upheld," said Dr. Roth, who has worked in rhino conservation for more than two decades.
"It is important that we learn from the plight of the northern white rhino and we make sure what happened to it does not happen to other endangered species,” he also said.
This last pair (both female) are thus the only remaining members of the world’s most endangered subspecies of mammal.
In a paper just published in Nature, he and his colleagues say that they have created, by in vitro fertilization (IVF), apparently viable hybrid embryos of northern white rhinos and their cousins from the south. This, they hope, will pave the way for the creation of pure northern-white embryos.
In the journal Nature Communications, Prof Thomas Hildebrandt, from the Leibniz Institute for Zoo and Wildlife Research in Berlin, and his international team of colleagues, described the complexities of safely extracting an egg, or oocyte, from a two-tonne female rhino.
"You can't reach the ovaries by hand, so we developed a special device," Prof. Hildebrandt explained to BBC News. "We used ultrasound to very precisely inject a needle into [the area of the ovary that releases] eggs."
This was done while the female southern white rhino was under general anaesthetic, but the process is still very risky. Located close to the ovaries, Prof Hildebrandt explained, is a "huge artery" that if punctured would probably cause the rhino to bleed to death.
But once viable eggs were safely preserved, the team then would have the challenge of fertilizing them with sperm from male northern white rhinos - animals that died long ago. They injected each egg with the sperm and used pulses of electrical current to stimulate the egg and sperm to fuse.
The result - viable embryos containing genetic material from a sub-species that is already functionally extinct.
"Everyone believed there was no hope for this sub-species," said Prof Hildebrandt. "But with our knowledge now, we are very confident that this will work with northern white rhino eggs and that we will be able to produce a viable population."
“Our results indicate that ART (assisted reproduction techniques) could be a viable strategy to rescue genes from the iconic, almost extinct, northern white rhinoceros,” the team behind the research wrote in the journal Nature Communications.
“Taking into account 16 months (of) pregnancy, we have a little more than a year to have a successful implantation”, Hildebrandt said.
This has not yet happened, however. The seven embryos are now in a freezer awaiting the results of research on how best to transfer them to surrogates. In the meantime, having proved their technique with these hybrids, Dr. Hildebrandt and his colleagues now hope to create more embryos, this time by using eggs from the last two remaining female northern whites.
Even if they succeed, though, it will be a long haul back for the northern white rhino. Members of any new generation resulting from IVF will have then to be bred with each other to create subsequent generations—with all the risks of reduced biological fitness which such procedure entails. It is not so much a gene pool that Dr. Hildebrandt is working with as a gene puddle.
Then there is the question of what to do with the resulting animals. Analysis of other rhinoceros species, both in Africa and Asia, points to a viable population in the wild needing to be at least 500 strong. Even if such a group could be created, and if it collapsed from lack of genetic diversity, releasing it into the tender remains of Kenya’s savannah would be risky. The reason the northern white has come so close to extinction—poaching—is unlikely to go away anytime soon.
Dr. Hildebrandt’s work is thus a half-step along what is likely to be a very long road indeed. Can these sustained efforts be enough to save the northern white rhino and all other endangered species? It is about to be tested. Soon.
The breakthrough has renewed hopes of preventing the northern white rhino from disappearing from the face of the earth.
Could this start the method of saving other endangered species?
Because of the uncertainties, the scientists are pursuing several different strategies. Besides trying to produce pure northern white rhinos, they also plan to transfer hybrid embryos into surrogates. Hybrids of white rhinos could help conservationists if they ever try to introduce them back to their usual habitat.
It also could be possible to use generations of inbreeding to dilute out the southern white rhino genes and get to something close to a pure northern white rhino—although that would require a small herd of the hybrids.
The international team of researchers successfully managed to adapt reproduction techniques used in horses to the special circumstances of rhino species, opening up the potential to bring back the northern white mammal from the brink of extinction.
"As impressive as science can be, we should not reach a point where these hi-tech approaches are the only source of hope for rescuing genes of valuable individuals, sub-species or entire species."
Aside from the Northern White, there are three other rhinos that are marked ‘critically endangered’ - Black Rhino, Javan Rhino, and Sumatran Rhino. Poaching and habitat loss also threaten their numbers as it continues to diminish significantly.
Sumatran rhino, another endangered species / Photo by Flickr.com