When it comes to rescuing a species or sub-species from extinction, prevention is better than cure.
Sadly, Northern white rhinos are now functionally extinct. Even if much-hyped innovations like rhino IVF are perfected in the future, it will likely come too late to save this sub-species. With only two related females remaining, the death of the last Northern white rhino is only a matter of time.
With small chance of healthy new calves, and limited place in their historic range to go, Save the Rhino believes that the best outcome will be to put our efforts and funding – including research into IVF – into saving the species that do still have a chance.
We can learn lessons from the Northern white rhinos’ sad demise – and stop the same fate befalling their Critically Endangered Javan and Sumatran cousins.
The Northern white rhino sub-species
Northern white rhinos are one of two sub-species of the white rhino, the other being the Southern white rhino. Also known as the Northern square-lipped rhinoceros, it has the scientific name of Ceratotherium simum cottoni. Currently, the sub-species is listed as Critically Endangered on the IUCN’s Red List of Threatened Species and “Possibly Extinct in the Wild”.
Northern white rhinos and Southern white rhinos ostensibly look similar and to the untrained eye are difficult to tell apart. The two sub-species do, however, display small but consistent differences in the limited research conducted on the diminishing population throughout the 20th and early 21st Centuries.
Northern white rhinos are believed to be slightly smaller than their Southern counterparts, with less prominent folding in their skin. Researchers point to their shorter legs relative to body length, higher head carriage, a less concave shape to their cranium, and the lack of the fine hair seen all over Southern white’s bodies; though hair does appear on the tail, muzzle, ears, belly and other localised areas (Groves, Fernando and Robovsky, 2010; Groves 1972; and Owen-Smith 2013).
According to geneticists, the two sub-species geographically split around a million years ago (Groves, Fernando and Robovsky, 2010), with Southern whites based in Southern Africa and Northern whites living in Central Africa.
Northern white rhinos once roamed in Uganda, Chad, across pre-partition Sudan, the Central African Republic (CAR) and the Democratic Republic of Congo (DRC).
The path to extinction
Rhinos across Africa first went into decline during colonial-era mass hunting and habitat loss as land was turned over for agriculture, livestock, plantations and urban developments. As the poaching crisis took hold in the 1970s and 80s, fuelled by demand for Traditional Chinese Medicine and Yemeni dagger handles, Northern white rhinos (and black rhinos) became extinct in Uganda, the Central African Republic (CAR), Sudan and Chad.
The last wild Northern white rhinos lived in a single population in the eastern DRC’s Garamba National Park until the early 2000s. Throughout the 1990s, numbers in Garamba National Park fluctuated between 20 and 30 rhinos. Two attempts were made to try and relocate animals to safer countries in Africa to create a second, “back-up” breeding population. The first, in 1995, involved a proposal to move some animals from DRC to another African country, provided that the two zoos holding NWRs (Dvur Kralove in the Czech Republic and San Diego in the USA) sent their animals to join them. The plan failed when the zoos decided not to move their animals.
The second, in 2005, foundered when a disaffected former Garamba employee stirred up regional dissent after the Congolese government had given its consent to a move of 4 or 5 animals from Garamba to Ol Pejeta Conservancy in Kenya. Ideally, the two zoos would then have moved their NWRs to Kenya to join this founder population. When the Congolese government changed its mind, this plan also failed. Realistically, this was the last chance to create a breeding population.
Garamba National Park, situated in eastern Congo, was the epicentre of violence during the Congolese Civil War, and suffered from multitudes of rebel and Janjaweed militia groups crossing its porous border. Harvesting ivory and rhino horn was one method these groups apparently used to raise funds for their operations. The last rhino conservation programme in Garamba National Park effectively closed in 2006, when fighting flared up again due to safety fears and the fact that the rhino population had declined to four, and was no longer a viable population with enough animals from which to breed. At the time, the Lord’s Resistance Army and Janjaweed raiders were operating in the Park, and are often blamed for poaching the last Northern white rhinos.
Surveys on the ground and by air in 2008 did not find any live animals or carcasses and, with no verifiable sightings subsequently recorded, it is assumed that the wild population is likely extinct.
What is the present situation?
In 2009, four Northern white rhinos were relocated to Kenya’s Ol Pejeta Conservancy from Dvur Kralove Zoo in the hope that their new surroundings, and other rhino companions, would stimulate natural breeding efforts. Unfortunately the animals failed to naturally reproduce.
Now, there are just two individuals left, a mother and daughter, and some conservationists are hoping to use Advanced Reproductive Technologies, like in vitro fertilisation (IVF), to help the animals breed. So far, 12 viable Northern white rhino embyros have been created using reproductive cells recovered from the current female and previous male rhinos.
Can Advanced Reproductive Technologies save the Northern white rhino?
IVF in rhinos is incredibly complex and it is unlikely that the methods required for its success will be put in place before the last Northern white rhino dies. Fewer than 10 rhino births have resulted from Artificial Insemination in the last 15 years, and only a handful of embryos have been successfully created. IVF has never been used successfully in rhino conservation and research has a long way to go until it becomes a proven method.
Furthermore, each rhino species has a unique physiology. For IVF to work successfully, it needs to mimic the uterine environment of the animal. As the last remaining Northern white rhinos are unable to carry a calf due to reproductive issues, scientists plan to use a Southern white rhino as a surrogate, which may bring challenges of its own.
Save the Rhino has an enormous amount of respect for the hugely talented scientists working on this project from San Diego Zoo and Leibniz Institute for Zoo and Wildlife Research in Berlin. The project has stimulated debate around the ethics of recreating extinct species, and whether this is the best use of funding available for conservation. Whilst it is unlikely that funding for the project has detracted from money available for in situ conservation, it is clear that anti-poaching work in African and Asia is increasingly expensive as the poaching threat has escalated, whilst demand reduction in consumer markets receives a fraction of all spending on wildlife conservation.
A practical concern for any future Northern white rhinos successfully bred through IVF is the question of where they would live. Much of the sub-species’ former range has lost rhinos in its entirety, with limited conservation programmes or expertise for managing a rhino population, and large-scale habitat loss. In any case, for the rhino population to be genetically viable, a minimum of 20, unrelated “founder individuals” are needed. Otherwise, a population becomes inbred and prone to genetic abnormalities – and fertility problems.
Advanced Reproductive Techniques might not save, or resurrect Northern white rhinos but, that said, there are other rhino species that are in peril, and technological advancements could help these species in the future. For example, Sumatran and Javan rhinos (Dicerorhinus sumatrensis and Rhinoceros sondaicus), both number fewer than 100 individuals.
What lessons can we learn from the sad demise of the Northern white rhino?
Lessons learned are being put into practice with other Critically Endangered species, making sure they don’t dip below 20 individuals, that habitat is secured, governments, zoos and international actors cooperate, and breeding is intensively managed.
The Indonesian island of Java is home to an estimated 74 Critically Endangered Javan rhinos. Their habitat is being expanded with strong backing from the authorities, and due to the proximity of an active volcano and the potential for natural disaster or disease to wipe them out, efforts are focused on allowing the population to diversify their range. Future plans include the creation of a second population to mitigate any stochastic threats, but that will take significant political will and funding.
On the neighbouring island of Sumatra, the Sumatran Rhino Sanctuary in Way Kambas National Park is home to seven of the remaining Sumatran rhinos. The intensive breeding programme, within a heavily protected natural habitat, has seen two new calves born, one in 2012 and another in 2016.
The team at the International Rhino Foundation are cryopreserving fibroblasts for Sumatran rhinos to preserve options for the future, and Dr Oliver Ryder’s lab in San Diego has kindly provided training in the methods to extract and preserve the cells. But the technology, which could help to increase numbers very slightly in the big scheme of things, may not be in place in time for Sumatran rhinos either. For these species, stringent protection in Intensive Protection Zones inside national parks, consolidation of fragmented populations, expanded captive breeding and creating a sense of ownership in local people offer the most hope.
With continued strict protection of both the remaining rhinos and their habitat, over the next century, the populations will hopefully be able to recover to at least 2,000 to 2,500 individuals, as this number is estimated by population biologists as a minimum requirement for the long-term survival of a species such as the Sumatran rhino.
Efforts to save the Northern white rhinos only received buy-in from the right people and organisations when the sub-species was already in a terminal decline. Now we’re better prepared – and taking action to make sure other Critically Endangered rhinos don’t suffer the same fate.
With thanks to Dr Kees Rookmaker, Chief Editor of the Rhino Resource Centre, for help with this article.