By Sicily Fiennes, Science Writer.
The Passing of Sudan
Last month brought the death of Sudan, the last male northern white rhino. Sudan passed away at the Ol Pejeta Conservancy in Kenya, East Africa at the ripe old age of 45. Sudan was put to sleep by veterinarians following age-related illnesses on March 20.
Sudan was one of the last northern white rhinos, a subspecies of the white rhino. Sudan’s daughter, Naijin and granddaughter, Fatu survive him as the only remaining members of their subspecies.
Even before Sudan’s death, the northern white rhino was termed ‘functionally extinct’, meaning this subspecies no longer fulfilled the ecological role they once had within the their ecosystem.
Rhinos are important grazers, and they’re critical for maintaining grassland communities in the savanna ecosystems. This was a role once filled by the northern white rhino. Their absence could have consequences as excess grass buildup leads to more intense and dangerous fires.
While we have lost a subspecies, we have not lost an entire species. The white rhino itself is recovering after historic decline, a recovery that stems from an increase in protected areas and sanctuaries across its range.
Saving the Subspecies
Although Sudan has passed, there is potential to revitalize the species using in vitro fertilization (IVF). Sperm and egg cells from 10 other northern white rhinos have been frozen, a necessary step since neither Naijin nor Fatu (Sudan’s descendants) can bear calves. Due to leg injuries, Naijin cannot bear the weight of a mounting male or of the calf, and Fatu has a uterine disorder that prevents her from getting pregnant.
Rhino reproduction is fundamentally complicated because they have corkscrew-shaped reproductive tracts, reaching 1.5 metres into the animal. Impregnation has proved difficult in captivity. Furthermore, it would take many cycles of this costly fertilization process to recreate a genetically healthy population before reintroduction to their native range is even considered.
As rhino populations continue to be threatened, solutions to the crisis span across a wide variety of methods. Dehorning has been proposed by many as a quick fix solution to the poaching crisis in Africa. Dehorning is a painless practice designed to limit the killing of wild rhinos by safely removing the keratinised horn. Beyond protection, these horns could potentially be used to flood the market, lowering the price and decreasing the appeal of ‘blood horns’ to poachers.
However, this has a negative effect on the fitness of mother and calf, and it’s been found that without her primary defense mechanism, mother rhinos were unable to defend their calves who suffered high infant mortality rates from spotted hyenas. Due to these factors, sustainable harvest is not a sustainable solution for wild populations of rhinos.
However, this could benefit rhino farms and enclosed sanctuaries such as the Private Rhino Owner’s Association. The association accounts for more than 6,500 rhinos, some of whom are dehorned. Many have questioned whether this is a façade for the illegal trafficking of rhino horn to Asia, where demand is highest. Rhino horn can fetch as much as $100,000 per kilo--a fortune to farmers. The difficulty in distinguishing between sustainably harvested horns and poached ‘blood horn’ could lead to a legal market flooded with both.
Sudan highlights the biodiversity loss we are currently witnessing and the ability of poaching to decimate entire populations of animals. However, while we can no longer protect the northern white rhino, we must not forget the fate of other threatened rhino species. In Indonesia, there are an estimated 67 Javan rhinos left and fewer than 80 Sumatran rhinos, low numbers that leave them critically endangered. The pressures of poaching and habitat loss that northern white rhinos faced are the same ones that confront these species.
We cannot rely on costly IVF technology to resurrect lost species. We must refocus critical funds towards conserving both recovering rhino populations and those that are critically endangered. The tremendous recovery of the white rhino reminds us that there is space for optimism in the rhino conservation story.
Now, it is up to us to see which strategy works best to ensure their survival.
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