The northern white rhino (Ceratotherium simum cottoni) is a subspecies of white rhino, which used to range over parts of Uganda, Chad, Sudan, the Central African Republic, and the Democratic Republic of the Congo. Years of widespread poaching and civil war in their home range have devastated northern white rhino populations, and they are now considered to be extinct in the wild.
As of 10 November 2018, there are only two rhinos of this subspecies left, both of which are female; barring the existence of unknown or misclassified male northern white rhinos elsewhere in Africa, this makes the subspecies functionally extinct. The two female rhinos belong to the Dvůr Králové Zoo in the Czech Republic but live in the Ol Pejeta Conservancy in Kenya and are protected round-the-clock by armed guards.
Najin (left), a female, was born in captivity in 1989. She is the mother of Fatu. Her father was Sudan (the last known male of this species).
Fatu (right), also a female, was born in captivity in 2000.
According to Save the Rhino, the best outcome will be to put the efforts and funding – including research into IVF – into saving the species which do still have a chance.
Scientists may hold key to saving northern white rhinoceros from extinction
Researchers from the U.K.’s University of Cardiff and the University of Venda in South Africa believe that genes from the less endangered southern white rhino could be used to save its critically endangered northern cousin.
In contrast, as many as 21,000 southern white rhinos exist in protected areas and private game reserves in Africa, according to the WWF. Most of these rhinos are found in South Africa, Namibia, Kenya, and Zimbabwe, it says.
University of Cardiff and University of Venda scientists analyzed genetic samples from 232 rhinos and discovered that, despite the populations of northern and southern white rhinos splitting over a million years ago, they have sometimes shared genes. Researchers say that genes have typically been shared during cold and arid periods, as recently as 14,000 years ago, when African grasslands expanded.
According to Dr. Isa-Rita Russo of Cardiff University: “By looking at the white rhino’s population history we’ve been able to establish that there was contact between northern and southern rhino populations throughout history”.
Genetic proof of contact between the populations suggests it may be possible to successfully rescue the northern white rhinoceros using southern white rhinoceros genes to create embryos, although further data would need to be collected to confirm this.
The team also found that population decline was very different in the north and south, with the northern white rhinoceros declining about 1,370 years ago, coincident with the Bantu migration, and the southern white rhinoceros declining during colonialism, starting 400 years ago.
This is one of the few large animals to survive the last ice age, and it seems that the additional human pressure on an already genetically compromised species has pushed the white rhinoceros further along the road to extinction.
Effect of poaching on the white rhino’s population
The current severe poaching epidemic is threatening and it is predicted that if present trends continue, the overall white rhino (both northern and southern) population will start to decline again in 2018. Efforts to curb recent losses are ineffective with only marginal decreases in poaching rates in 2015 and 2016, with more than 1000 African rhinoceros killed every year since 2013. Such a population contraction, in the absence of gene flow from other sources, could negatively affect the genetic diversity and evolutionary potential of the rhinos through genetic drift.
BRENT STIRTON: Special Investigation: Inside the Deadly Rhino Horn Trade, National Geographic
The contrasting histories of the northern and southern white rhinoceros have substantial implications for their conservation. Low diversity at both mtDNA and microsatellite loci implies that maintenance of genetic diversity should be a core conservation action for the species.
With most endangered species intensive genetic management of populations would be prohibitively expensive and/or logistically challenging.
The situation for the Northern White Rhinos is very different, and this population is the endpoint of a long period of both prehistoric and anthropogenic decline. With only two female individuals remaining, the role of genetics is presently confined to an evaluation of the potential outcomes of hybrid rescue involving the use of Southern White Rhinos genomes.