Black Rhino
The black rhinoceros, or Diceros bicornis, is a mammalian herbivorous browser. The International Union for Conservation of Nature recognizes 5 subspecies of black rhino, 2 of which are extinct. The remaining species are the South-central black rhinoceros, the Eastern black rhinoceros, and the Southern black rhinoceros. All three of the remaining subspecies are considered critically endangered, and all three are found in southern and eastern Africa. 1
Diet and Habitat
The habitat of the black rhino includes the semi-desert savannah, woodlands, forests, and wetlands. 1 Generally speaking, the most suitable habitat will have high densities of woody species. In South Africa, two of the primary locations in which black rhinos are found are Kruger National Park, and Hluhluwe iMfolozi Game Reserve. Kruger National Park spans over 7,523 square miles and contains 13 distinct habitat types, many of which support black rhino populations.2Hluhluwe iMfolozi Game Reserve supports an even larger population of rhinos than Kruger, and has been nationally recognized for their rhino breeding initiatives in the 1950's and 1960's.3 There are many other parks and reserve that support black rhino populations throughout South Africa, and provide much needed habitat.
Rhinos are considered herbivorous browsers, meaning they primary eat woody plant species. Black rhinos have showed a preference for Acacia species, as well as Phyllanthus fisheri. However, there are at least 103 different plant species rhino have been known to consume .4 Competition with both elephants and giraffes can cause rhinos to adjust their diet preferences. Of course, rhinos need water to survive, but due to their thick skin (which prevents desiccation), they can go up to 5 days without drinking.4
Life History
Female rhinos reach sexual maturity at age seven, have a 15-month gestation period, and a calving period (the time between births) of 2-5 years .5 The average age of final parturition was 30, indicating that a female can birth between 5-10 calves in her lifetime.6 In almost all cases, only one calf is produced during pregnancy. Females also undergo estrous cycles, which primarily differ from menstrual cycles in that they reabsorb the endometrium, instead of shedding it.7 The average lifespan for both females and male is 40-50 years. Male rhinos begin reproducing at age 7 in the wild, and at age 4.5 in captivity. Males are polygynous and mate with multiple females. They have little to no parental involvement with their offspring.5
Cultural Significance
The black rhino has shown to have cultural significance in regions across the world. There have been recovered artifacts which date back to around the 10th century, which depict rhinos. This indicates a deep relationship between human culture and rhinos. (Figure 2) In Bantu speaking regions, the black rhino was traditionally viewed as a symbol of leadership. The strength and fortitude needed in a tribal leader is reflected in the physical power and solitary nature of the black rhino. The horn of the rhino represented these traits best, demonstrating aggression, authority, and protection. There was also utilization of the horn of the rhino in traditional practices, including using it as a vessel for rainmaking medicine. Both the Venda and Shona peoples have traditional “rhinoceros dances”, which most likely are inspired by the stomping behaviors of the rhino. The dance for the Venda people was done to suppress sexual activity, when a new chief was chosen, as a way to prevent the new chief from having illegitimate children. For the Shona people, the rhinoceros dance was done as a way to bring rain, and to thank the ancestors. 8
In Eastern culture, the rhino takes on a slightly different cultural role. The horn is the rhinoceros is valued for its traditional medicinal uses. The use of rhino horn for medicine is seen most often in China, Taiwan, and Vietnam. It is believed that the rhino horn has a superior connection to heaven – a belief which drives the idea that powder derived from the horn of a rhino can cure disease. This is compounded by the belief that the horn can be used as a “detoxification” method. This belief most likely came about as people observed the rhino’s ability to eat plants that were considered poisonous, but survive. These beliefs drive a market for rhino horn, with the idea that used to cure anything from a fever, to sexual dissatisfaction. The Chinese also utilized the hide of the rhino for armor, as well as for creating imperial belts as a sign of power and authority. 9
Threats
Habitat loss
Habitat loss as a result of anthropogenic disturbances is one of the main factors affecting black rhino populations .10 As human populations in southern Africa grow, habitat loss and fragmentation increase. The current population of South Africa is approximately 57 million, and the country has a population growth rate of 1.2%.11 Thus, the effects of anthropogenic habitat loss will most likely increase in the upcoming years. Rhinos are solitary animals that have a large range (often referred to as a “house”) that they frequently re-visit, potentially due to an abundance of resources. This “house” size can span from 3 km2 – 130 km2.12 Habitat loss can severely constrain the range of the rhino, which effects their access to resources, may increase intraspecific competition, and potentially decrease overall fitness.
Poaching
The biggest threat black rhino face is illegal poaching - and if the current rates of poaching continue, the wild black rhino population may be extinct by 2040. 1 A financial boom in Asia in the mid-2000’s allowed for a larger demand for rhino horn. This drastic increase in money within the market lead to the creation of crime syndicates that have the funds for better weapons and transportation.14 These poaching crime syndicates pose an enormous threat to the black rhino population. Also, there is a lack of training and financial support to the rangers in national parks and private game reserves (largely as an aftereffect of the Apartheid). This combination of the strength of the crime syndicates and the lack of support for the rangers contributes to a vast increase in the amount of poaching. In 2017, 1,028 rhinos were poached in South Africa alone. This is a drastic increase from the 13 that were poached a decade ago in 2007.13 The primary cause for this poaching is to supply rhino horn to the traditional Chinese medicine market. Rhino horn is so valuable that is it worth more per weight than either diamonds or cocaine.14 There is only one case of rhino horn being sold in the United States, which occurred in Oregon in June 2007.15
Conservation
In the early 1900’s there was most likely hundreds of thousands of black rhino in the wild. However, by 1933, there were only 110 black rhinos left in the world, with only 2 viable breeding populations. This was most likely due to overhunting. In the 1950’s and 1960’s, mitochondrial analyses showed little variation among the populations and demonstrated a need to diversity. So, breeding efforts began through a program called Operation Rhino. This was largely done out of Hluhluwe iMfolozi Game Reserve, under the guidance of Dr. Ian Parker. 16 The project was done by using very hands-on conservation approaches, and managing the individual rhinos very specifically. Certain rhinos would be chosen to be translocated to another population in order to increase genetic diversity. This would usually be done by a system of darting the rhinos to inject a sedative, and then transporting by helicopter.17 This project had exceptional success – by the late 1960’s there were around 100,000 black rhinos in the wild. This project had become a point of pride for many South Africans and became slowly integrated into the cultural identity. However, by the mid 2000’s those numbers had dropped significantly (primarily due to poaching), and it is now estimated that 5,042-5,455 black rhino remain in the wild. There are also many rhino protection zones, which have armed guards and fenced sanctuaries. These intensive protection areas are a way to concentrate law enforcement in one area, to prevent illegal poaching.16 Black rhino conservation is complex and is multifaceted, as there is both private and public management within South Africa, and the added complication of cooperation with neighboring countries which have rhino populations.
In October 2018, China announced that rhino horn (and tiger bone) would be legalized for mainstream medicinal use, even though there is still virtually no empirical evidence demonstrating that rhino horn has any effect on human health. Chinese officials have yet to explain the sudden decision to reverse the legalization. 18There is debate among conservationists on this decision. Some believe that this decision would have helped rhino populations overall, and that by regulating the trade, illegal poaching would decrease and that more ethical methods of de-horning would become commonplace. However, many were outraged, and believed that this decision would only hurt black rhino populations, and would give poachers a larger market, as well as a “legal cover” to hide beneath. This outrage most likely contributed to the decision (one month later in November 2018) to postpone enacting the legalization until “further research” could be done. A statement was given by Secretary General Ding Xuedong to the media, saying that “the issuance of the detailed regulations for implementation has been postponed after study”.19 It is unknown if and when the legalization will be enacted, and what effect it will have on black rhino conservation.
References
(1) Emslie, R. 2012. Diceros bicornis. The IUCN Red List of Threatened Species.
(2) Retrieved from https://hluhluwegamereserve.com/about-us/</font>
(3) Retrieved from http://www.krugerpark.co.za</font>
(4) Oloo, T.R., R. Brett, and T.P. Young. 1993. Seasonal variation in the feeding ecology of black rhinoceros (Diceros bicornis L.) in Laikipia, Kenya. African Journal of Ecology 33: 142-157.
(5) Freeman, E.W., J.M. Meyer, J. Bird, J. Adendorff, B.A. Schulte, and R.M. Santymire. 2014. Impacts of environmental pressures on the reproductive physiology of subpopulations of black rhinoceros (Diceros bicornis bicornis) in Addo Elephant National Park, South Africa. Conservation Physiology 2: 1-13.
(6) Nhleko, Z.N., D.M. Parker, and D.J. Bruce. 2017. The reproductive success of black rhinoceroses in the Hluhluwe–iMfolozi Park, KwaZulu-Natal, South Africa. Koedoe 59: 1-10.
(7) Lombardi, J. 1998. Comparative vertebrate reproduction. Boston, MA: Kluwer Academic Publishers.
(8) Boeyens, J.C.A, and M.M. Van der Ryst. 2014. The cultural and symbolic significance of the African rhinoceros: a review of the traditional beliefs, perceptions, and practices of agropastoralist societies in southern Africa. Southern African Humanities 26: 21-55.
(9) Zhang, G., and M. Harris. 2013. China and the Rhino. Nikela: 1-14.
(10) Rhinoceros. African Wildlife Foundation. Retrieved from https://www.awf.org
(12) Kurnit, Jennifer (2009). Diceros bicornis/black rhinoceros .Animal Diversity Web. Retrieved from https://animaldiversity.org
(13) Bale, Rachael. 2018. More Than 1,000 Rhinos Poached in South Africa Last Year. National Geographic. Retrieved fromhttps://news.nationalgeographic.com
(14) Biggs, D., F. Courchamp, R. Martin, H.P. Possingham. 2013. Legal Trade of Africa's Rhino Horns. Science 340: 1168-1169.
(15) Patte, David. 2007. Portland Man Pleads Guilty to Selling Black Rhino Horn. U.S. Fish & Wildlife Service. Retrieved fromhttps://web.archive.org
(17)Hofmeyr, J.R., J.M. Ebedes, H. Fryer, R.E.M. and D. Bruine. 1975. The capture and translocation of the black rhinoceros Diceros bicornis Linn. in South West Africa. Madoqua 2: 35-44.
(18) China to control trade in rhino and tiger products. 2018. The State Council. Retrieved fromhttp://english.gov.cn
(19) Full transcript: State Council Executive Deputy Secretary-General Ding Xuedong Answers Media Questions. 2018. Retrieved from China.org.cn
