Rhino Husbandry Manual
The Cause of the Crisis
Rhino species have faced many different challenges over the past few decades. As with many endangered species, fragmentation and loss of habitat is an important factor, but not the major cause of the rhino’s decline. The greater global problem is overexploitation through poaching for rhino horn. Rhino horn has been used for centuries in traditional Chinese medicine as a fever reducer. China has been the primary consumer country until recently. Now, the burgeoning market is in Vietnam, where the economy has rapidly grown and purchasing power is increasing. In addition to traditional use, rhino horn also has been touted as a cancer cure and a purported hangover preventative in Vietnam. It also is given as a high-value gift item. In the Middle East, horn has been used to make dagger handles that confer social status, but this threat has paled in comparison to the growing consumption in Asia.
In the middle of the last century, all five rhino species were widely distributed and most abundant throughout Asia and Africa. As of mid-2025 only about 27,000 rhinos of all kinds survive in the wild.
Crisis For Rhinos
In the middle of the last century, all five rhino species were widely distributed and most abundant throughout Asia and Africa. As of mid-2013 only about 29,000 rhinos of all kinds survive in the wild. As of 2025, approximately 27,000 rhinos survive in the wild. Another 865 exist in captivity (Table 1.1). However, more than 80% 60% of these rhinos, both in the wild and in captivity, are of a single species, the white rhino (Ceratotherium simum).
The other four species combined comprise fewer than 8,500 individuals. Populations have been growing for the past several years for all but the Sumatran rhino (Dicerorhinus sumatrensis), which has rapidly decreased, and the Javan white rhino (Rhinoceros sondaicus), which we believe has remained relatively stable (Fig. 1.1). In addition, the Javan rhino Although there has long been a debate among conservationists as to whether subspecies are different enough that they should be conserved as separate units, in some cases, such as the Sumatran and Javan rhinos, subspecies issues are superseded by the species’ severely limited numbers. This provides only a small number of management options—the least of which may be genetic in nature.
The Sumatran rhino, in 2024, is the rarest of the species with a total population estimated to be between 44-57 animals, including 10 in captive management. Though the Sumatran Rhino Sanctuary has had three births since 2022, poaching and fragmented populations continue to be looming threats. Though slightly more stable, Javan rhinos also remain on the cusp of extinction. The last individual of the Javan rhino
subspecies Rhinoceros sondaicus annamiticus was declared extinct in Vietnam in 2010 by World
Wildlife Fund and the International Rhino Foundation; now only one population remains in
Indonesia’s Ujung Kulon National Park (Brook et al., 2012). However, while the Javan rhino is fewer
in number, the Sumatran rhino’s rapid decline (roughly 75% over the last 20 yr) makes it the most
critically endangered of all the rhino species and perhaps of any large mammal. The IUCN officially
declared the northwestern black rhino (Diceros bicornis longipes) extinct in the wild in 2013, and
the northern white rhino (Ceratotherium simum cottoni) became extinct in the wild in 2008.
There are, however, success stories in rhino conservation. With concerted government
commitment and efforts by dedicated conservationists, including protection and consolidation
of populations, three of the five rhinoceros species have slowly recovered from the brink of
extinction. Southern white (Ceratotherium simum simum) and greater one-horned or Indian rhinos
(Rhinoceros unicornis) have both come back from fewer than 100 animals in the early 1900s, now
numbering more than 16,000 and 4,000 respectively. Black rhinos (Diceros bicornis) faced a serious
poaching crisis in the early 1990s, which led to the loss of 97% of the population. Management
measures, including consolidation of populations through targeted translocations, strategic
dehorning, and active protection have helped the species recover to more than 6,000 animals,
most living in fragmented populations. Significant black rhino populations now survive in only
twelve countries. Unfortunately, rhino poaching is now
rampant again, with poaching losses threatening to overshadow previous conservation progress in
population growth.
How Can We Help?
Conservation of Rhinos
If rhinos are to survive long-term in the wild, they must be intensively managed and protected, with a spectrum of options to maximize options for the future need. These options represent a continuum with respect to intensive management required and range from management within protected areas or semi-free-ranging reserves to conservation centers to zoos. Zoos and conservation centers may increasingly provide key portions to the available options within the conservation spectrum. Animals in these facilities can play a number of important roles, serving as: (1) ambassadors for their wild counterparts; (2) instruments for education for local communities and the general public-at-large, (3) research populations that allow scientists to learn as much as possible about the basic biology of species (which may be difficult to study in nature); (4) ‘flagship species’ to protect and call attention to other threatened wildlife that share their habitat; (5) an ‘insurance’ population that can be used to re-establish or revitalize wild populations that have been severely reduced or extirpated (provided that adequate protection measures can be put in place in former ranges); and (6) a means to attract attention and support, financial and otherwise.
However, it must be emphasized that ex situ populations and programs are not a be-all and end-all in themselves; the primary purpose
should be to support applied learning that can be used to assist the survival or recovery of the species in the wild. As the rhino crisis intensifies, expertise in small population management may become more and more important. For some species, such as Sumatran, Javan and black rhinos, implementation of these principles may hold the only hope for future survival. Zoos and conservation centers are well-positioned to provide inputs using examples from highly-organized and scientific programs such as Species Survival Plans (SSPs). SSPs have traditionally been managed in the United States and Canada by Species Coordinators and Management Committees in cooperation with Taxon Advisory Groups (TAGs), which provide strategic perspectives and technical advice for SSPs and participating rhino-holding institutions. Managed breeding, however, is not all genetics and demography. Basic husbandry, how to maintain healthy individuals and induce them to breed, is fundamental. There are major challenges for rhino husbandry in zoos and conservation centers, which may present some of the most formidable captive management challenges of any species. As a consequence, all taxa of rhinos maintained in zoos and conservation centers are in some degree of demographic difficulty. These demographic problems are causing genetic difficulties because some lineages are at risk of being lost as their representatives are not reproducing. Clearly, husbandry, demography and genetics interact; and all three are crucial to the conservation of rhinos, especially in managed breeding situations. Husbandry problems can impede intensive management of rhino species. Specific problems include poor survivorship and high mortality, poor reproductive success and a fundamental lack of knowledge regarding basic rhino biology.
Species
The Status of Managed Rhino Populations within AZA
Diceros bicornis
Rhinoceros unicornis
Ceratotherium simum simum
Rhinoceros sondaicus
Dicerorhinus sumatrensis
Poor Survivorship/High Mortality
The browsing rhinos, black and Sumatran, in particular have problems with poor survivor- ship/high mortality under intensive management. The black rhino has been afflicted with many health problems (e.g., hemolytic anemia, severe ulcers on skin and mucous membranes, liver dysfunction). Both species are affected by iron storage issues, which may lead to other complications.
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Poor Reproductive Success
Reproduction in all four of the species that have been maintained in zoos and conservation centers is less than optimal. In general, greater one-horned, black and, to a lesser extent, white rhinos reproduce well in managed breeding situations if species-specific needs are met. Captive managers are still struggling to understand the spectrum of these needs. Although reproductive challenges have now been overcome for the Sumatran rhino, the learning curve was very steep before the species could be reliably maintained and bred. For no species of rhino in captivity is reproduction reliable or routine.
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Poor Understanding of Basic Biology
Compared with many other groups of organisms under intensive management, aspects of the basic biology (e.g., nutritional, reproductive, behavioral) of rhinos is poorly known. Nutritional problems are suspected to be of particular significance to the health and perhaps the reproductive difficulties of rhinos, particularly the browsing species. Behavioral issues also may interfere with successful husbandry. Various physiological and psychological challenges are believed by some researchers and managers to be underlying causal factors for many of the specific disease syndromes in rhinos. In recognition of husbandry challenges, a major goal of SSPs and the TAGs that facilitate them is the production of husbandry manuals, which can lead to successful management and propagation of species in captivity.
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The Future
In the coming decades, as rhino husbandry and small population management are refined in zoos and conservation centers, these techniques will undoubtedly have broader application to the intensive management of increasingly fragmented wild rhinoceros populations. Ex situ populations can contribute positively to the conservation of rhino species in nature, but only if we use these populations to gather as much information as possible that can be applied to proactive management in situ. Rhino-holding institutions also have the obligation to educate the public about the plight facing this magnificent taxonomic group, which grows more imperiled every day.
Photo courtesy of International Rhino Foundation (2025)