Author: Alice Stuart-Brown
With only two females left, the Northern White Rhinoceros (NWR) is nearly extinct, but a revolution in fertility treatments may pave the way to the species’ resurrection.
The two surviving NWRs live in a Kenyan nature reserve, where armed guards protect them around the clock. They once roamed the planes of Uganda, Southern Chad, and South Western Sudan, but political unrest led to a growing demand for rhino horn, which in turn led to an increase in poaching in these countries.
The decline in wild NWR numbers began in the 1970s, when armed conflict throughout the decade left only a small population located in Garamba national park in the Democratic Republic of Congo. A survey at the park in 2008 showed the rhinos to be completely extinct in the wild. The remaining four rhinos were flown from the Czech Republic and California to Kenya in a bid to breed them, but no calves were born and one of the males passed away suddenly in 2013. The last male died of old age in March 2018.
Moral objections often arise when fighting for the conservation or preservation of a species; the idea of ‘playing God’ or intervening with natural selection leads to arguments against their protection. However, proponents for species preservation argue that NWRs act as a blanket species. This means that their demise would lead directly to the demise of other species.
Saving the rhino not only affects the ecosystem but also benefits the economy of the African countries in which they reside. As the third largest animal in Africa, they attract huge populations of tourists, and tourism accounts for 44.5bn USD of the GDP of Africa.
A fertility revolution has arisen from many years of work with the southern white rhino (SWR), the other white rhino subspecies. Because very few NWR eggs have been stored, SWR eggs have been fertilised with NWR sperm to create hybrid embryos to ensure the general technique works. The next step is critical: the same technique will be used, but the SWR eggs will be replaced with NWR eggs to create a pure NWR. Once a pure NWR embryo is created, a female SWR can act as a surrogate mother, carrying and giving birth to the calf. Once breeding pairs are created, conservationists will work to ensure the population is rebuilt and the NWR is protected.
After thorough testing, conservationists are confident that this method will go a long way towards restoring the rhino population.
However, there are risks in the practicality of the treatment. Implanting the embryo requires the surrogate to be kept under anaesthesia for at least two hours. Anaesthetizing rhinos is common place for conservationists in marking, collection of samples, and medical treatments, but the process is complicated by the rhino’s sensitivity to opioids and possible breathing problems while under anaesthetic.
IVF carries its own risks, and the success rate of zoological IVF can be as low as 15%. With limited supplies of NWR eggs, implanting them means the risk of losing them.
The suggested method of fertility treatment will lead to a lack of genetic diversity, as all the eggs used would come from the two living females. If genetic faults permeate throughout the population, it can lead to a loss of the whole species.
The solution to this problem may lie in stem cell development. If normal skin cells of the NWR can be manipulated they can be used in fertilisation, eliminating the lack of diversity. Scientists do this by collecting pluripotent stem cells from the bone marrow of the adult rhino; these cells can differentiate into any type of cell when placed in the right environment. These cells can become egg and sperm cells which can be fertilised. Scientists can then implant the resulting embryos in an SWR surrogate.
Conservationists also argue that releasing rhinos back into the wild will not solve the problem, as the underlying issues have not been dealt with. Poaching laws need to be stricter and habitats need to be protected to stop the issue resurfacing.
The Northern white rhino isn’t the first to be on the brink of extinction. In 1961 the WWF launched a campaign that bought the Kenyan black rhino population up from 539 to roughly 5,000. Combining these techniques with fertility treatments could lead to a thriving NWR population in the next 50 years.
Rhinos that have been shaping the landscape and ecosystem for centuries and many species rely on their survival. In working to save the rhino, researchers are indirectly protecting many other species.