Black Rhinos and White Rhinos: Counts, COVID and Conservation

As caregivers, parents and teachers of children, we try to encourage and respect every youngster’s individuality. We tell them that they are each unique and that every one of them has something separate to give, something different to learn and something distinct to create.

But when we speak of wild animals, it is often in the aggregate or group sense that we describe their worth. For example, we talk about how monarch butterfly populations are dwindling or tiger numbers are plummeting.

But Africa’s black rhinos are showing us that other individuals in the animal kingdom really do matter—especially when assessing survival chances. Poaching has effects on rhinos beyond the deaths of the targeted individuals. The loss of healthy females that would have gone on to produce lots of calves can make whole populations even more vulnerable to extinction.

White rhinos, too, are causing us to pay more attention—a result of the coronavirus pandemic—to the finer intricacies of conservation. Saving them saves habitats; countries, even; which saves us from worldwide pandemics.

Black rhinos: numbers didn’t tell the whole story

According to World Wildlife Fund, rhinos are one of the oldest groups of mammals, making them virtually living fossils. They play an important role in their habitats. In countries such as Namibia, rhinos are an important source of income from ecotourism; and their protection creates large blocks of land for conservation purposes, which benefits many other species, including elephants.

Of the two African rhino species, black rhinos are the smaller. The most notable difference between a black rhino and a white rhino is seen in their upper lips: a black rhino’s is hooked, while a white rhino’s is square. Black rhinos are browsers rather than grazers, and their pointed lips help them feed on leaves from bushes and trees. They have two horns and, occasionally, a third, small, posterior horn.

In the 20th century, populations of black rhinos declined dramatically at the hands of European hunters and settlers. Between 1960 and 1995, black rhino numbers dropped by 98 percent, to less than 2,500. Since then, however—thanks to persistent conservation efforts across Africa—the species has made a tremendous comeback. Black rhino numbers have doubled from their historic low 20 years ago to around 5,500 today.

Black rhinos, unfortunately, are still considered critically endangered. Wildlife crime—in this case, poaching and black-market trafficking of rhino horns—continues to plague the species and threaten its recovery.

But numbers alone don’t tell the whole rhino story. Recently, Kenyan conservationists and scientists and researchers from England’s University of Manchester examined data from black rhino populations in Kenya, which suggest that individuals really matter when assessing the impact of poaching on the animal’s survival chances. Their results, published in the science journal Proceedings of the Royal Society B in April 2022, demonstrate that poaching—combined with individual rhino’s reproductive variance, or how successful moms are at raising young—leads to an increased extinction risk by as much as 70 percent, much more than first thought.

Within black rhino populations (and probably in most animal populations), some individuals have more babies than others. This variation increases existing estimates of extinction risk, especially when there is poaching. Indiscriminate killing can lead to some of these important animals, which contribute a greater number of offspring, being removed.

This research is important because it shows that we may underestimate risk (or overestimate viability) if we do not recognize that some individuals contribute a lot more to the population than others and that their particular loss will have a much bigger impact.

Estimating extinction risk can be affected by differences in breeding success between individual females (called reproductive skew), but reproductive skew is not often included in predictions of future population growth because it requires detailed individual breeding histories. Luckily, that information was available for eastern black rhinos because of intensive monitoring to protect them from poaching. Kenyan rhino managers, scientists and security teams have meticulously recorded births and deaths for decades. Across three Kenyan populations of black rhinos on the Lewa Wildlife Conservancy, the Ol Jogi Wildlife Conservancy and the Ol Pejeta Conservancy, the researchers found that there is significant variation in breeding success between females, with many females not breeding or doing so very slowly.

This study highlights a deadly combination of individual differences, small numbers and poaching for vulnerable populations. When working in combination, these factors can completely reshape the fate of an endangered species. Crucially, variation in female breeding success can exacerbate the effects of poaching, especially on small populations.

It may be possible to even out the variation in breeding success by creating new rhino reserves, moving rhinos between current reserves or even creating more valuable habitat; but if key individuals, ones that breed very well, are still killed, the whole population will remain more vulnerable to extinction. Such differences between individuals in their contribution of young to at-risk populations is likely an issue across many more species and should be evaluated when assessing their risk of extinction.

White rhinos: COVID didn’t completely curtail conservation

The COVID-19 pandemic, of course, has changed the lives of people everywhere and affected cultural, economic, political and social processes. Research and conservation did not escape these negative effects. Still, some say that the “Anthropause” on the environment had some positive consequences.

Take the BioRescue project, for instance, a program aimed at saving the northern white rhinoceros from extinction. COVID-19 hampered communications and travels, prevented or delayed crucial procedures and caused losses in revenues that may have lowered the chances for the northern white rhino to survive.

On the other hand, during the pandemic—as described in detail in a scientific paper published in the Journal of Applied Animal Ethics Research in January 2021—the project was able to adjust strategies, continue with its mission and gain valuable knowledge.

There are only two northern white rhinos left on the planet, both females. To prevent this animal’s extinction, an international team of conservationists and scientists are using assisted-reproduction technologies and stem-cell-associated techniques to create northern white rhino embryos in vitro. Those embryos will then be transferred to southern white rhino surrogate mothers to create northern white rhino offspring.

Since March 2020, however, work has been severely affected by the COVID-19 pandemic. International travel restrictions have been one of the most difficult obstacles. BioRescue research partners had previously agreed upon collecting eggs from the last two northern white rhinos every three to four months. This is considered a safe interval to maintain the health of the females while maximizing the number of harvested eggs. A collection was planned for March 2020 at the Ol Pejeta Conservancy. But owing to international travel restrictions, the procedure had to be canceled and could only be conducted after the reopening of Kenya’s borders in August 2020. This not only meant that one crucial opportunity was missed and possibly several valuable embryos could not be generated, it also affected the August 2020 procedure. It’s likely that the prolonged interval since the last egg collection in December 2019 compromised quality and was the reason that out of 10 eggs collected, no embryos could be created.

This postponement of possible embryo transfers in Kenya will also decrease chances for northern white rhino calves to grow up with individuals of their kind. Ultimately, then, almost a year was lost for the program, which is a serious delay in the race against time to prevent the extinction of the northern white rhino.

In addition to the delays in conducting the procedures at Ol Pejeta Conservancy in Kenya, the not-for-profit conservancy experienced drastic reductions in revenue from international tourism owing to a ban on international travel, national curfews and the isolation of the capital Nairobi.

For BioRescue’s research partners in Germany, Italy and Japan, different levels of restrictions were put in place on laboratory work. Some vital work at laboratories in Germany and Japan could be carried on to a limited extent, but lab staff was cut back, transportation of samples and equipment was hampered, and closure of schools and childcare facilities forced parents to switch from in-lab work to work at home.

Besides the negative effects of the pandemic, though, there were also a few positive ones. The involuntary break provided researchers with valuable, new insights into the reproduction management of northern white rhinos. Closure of international borders opened new opportunities for assisted-reproduction procedures in Germany, which were important for advancing and perfecting methods and techniques. For example, a designated mating partner of a southern white rhino female in a German zoo could not be transferred and, therefore, assisted reproduction was a welcome alternative to natural mating. Secondly, social distancing regulations helped to establish a new culture of online meetings for BioRescue’s partners on a more regular basis, which proved useful and will continue. Lastly, there is a renewed public awareness for the destruction of habitat and the loss of biodiversity as key drivers for emerging zoonotic diseases.

Despite all the difficulties, the researchers state that during the pandemic, ethical monitoring was always performed and BioRescue’s procedures have uninterruptedly maintained high standards of quality and respect for the safety and welfare of both researchers and the animals involved.

In the end, BioRescue proved not only to be about saving the northern white rhino. It was also a much-needed step for the healing of disrupted habitat in Central Africa and thereby preventing global pandemics in the future.

Black rhinos and white rhinos: the individual and the collective

Preventing population declines is a crucial step for stopping biodiversity loss. But we now know that it’s more nuanced than that: losing key animals, such as those among the black rhinos, can make small populations even more vulnerable, which should help in designing more effective conservation actions.

It is somewhat ironic, however, that the mission to protect northern white rhinos from going extinct was severely affected by the very thing it ultimately intends to make more unlikely: a pandemic.

The prepandemic and pandemic lessons learned from black rhinos and white rhinos will, hopefully, teach us adults about the importance of not only our own kind as individuals but of other animals, as well—alongside their worth to world biodiversity as population groups.

Here’s to finding your true places and natural habitats,

Candy