There are five living species of rhinoceros: black (Diceros bicornis), white (Ceratotherium simum), Javan (Rhinoceros sondaicus), Indian (Rhinoceros unicornis), and Sumatran (Dicerorhinus sumatrensis) rhinos. And not too long ago there was a woolly rhino (Coelodonta antiquitatis) that roamed northern Eurasia until it went extinct ~14,000 years ago. The IUCN lists black, Javan, and Sumatran rhinos as critically endangered, the Indian rhino as vulnerable to extinction, and the white rhino as near threatened.
Rhino populations historically declined due to over-harvest because of high demand for rhino horn, as well as some habitat loss. In the early 1990s populations began rebounding as international trade policies pressured high consumption countries to curtail imports. Monitoring of population sizes showed that white rhino populations grew 7% annually from 1992 to 2010; similarly, black rhino populations doubled in size during this time. However, population growth has leveled off or declined due to renewed demand for rhino horn and increased poaching to fuel black market trade. Rhino horns are valued both for decoration (e.g. bracelets, cups, dagger handles) and for traditional Asian medicine. Like many black market goods, rarity and scarcity increase prices; however, in keeping with the Rhino Species Specialist Group policies, I will not publish estimated black market prices (the link is to an explanation of this policy). Since trade in horns is the overwhelming conservation threat, there have been multiple solutions suggested to curb poaching.
When a rhino is dehorned, it is anesthetized then the majority of its horn, as close to the skin as possible, is removed. Due to the way that rhino horns grow, horns can be considered a renewable resource as it will regrow in ~3 years. The goal of dehorning is to discourage poaching; however, this is not fully effective in part because the horns continue growing and/or there is horn underneath the skin. In October 2017, an entire herd of five individuals were killed despite being dehorned, with evidence that remnant bits of horn were dug out of the faces. Field reports like this are particularly discouraging because dehorning seems like such a practical solution to non-experts like myself. But this only highlights the amount of risk poachers are willing to take for very little reward. That said, the counter-factual is unclear: how many dehorned rhinos were not poached due to their dehorning.
An admittedly controversial idea is to set up a legal market for rhino horn trade. As a concept, legal trade would disincentivize poachers as rhino horn could be sourced from natural mortalities, dehorning efforts, and seizures of illegally harvested horns. Problems with this approach are numerous including: could a legal supply meet current demand, how would a legal supply change demand, and who profits from a legal market place. If income from legal sales did not reach current poachers, it is unclear if the black market would continue.
A very interesting piece of research investigated attitudes towards legal and illegal rhino horn markets using a willingness to pay survey in Vietnam. The survey found that consumers preferred illegally harvested rhino horn and would only pay 60-70% for legally harvested horn (if a market were established) compared to illegal horn. The researchers noted that the illegality was an important part of the decision to purchase because rhino horn is a status symbol in Vietnam. Cultural differences in China and Yemen may show different results for preference of legal vs illegal horn sources; however, those surveys have not been performed (or at least reported).
Decreasing the demand for rhino horns is paramount to global conservation efforts. One tactic has been to remove products from sale online using national conservation laws. This was only somewhat effective in China as sellers migrated to social media platforms where monitoring became harder. Education is a second strategy to decrease demand. Efforts include informing consumers that rhino horn is not a cancer cure (a common use) nor useful for other medical ailments or virility. Interestingly, the IUCN cautions against using conservation or anti-poaching messages in educational efforts as it is not effective in changing consumer attitudes. The survey in Vietnam revealed that education campaigns did not change consumption patterns for 97% of consumers; instead respondents noted that heavy financial penalties or jail were more likely to deter their use.
Hope for Rhinos
Talking about rhinos tends to be a sad conversation with constant reports of slaughter on the range, or natural deaths of zoo animals (decreasing captive breeding capacity), or even museum robberies because that is how desperate people are for sources of horns. But there is hope for rhinos. Population trends turned around in the 1990s and 2000s due to concentrated international cooperation to decrease trade. And these are not pandas (#worstbear), they will make cutie rhino calfs. Thus, if trade demand decreases, the future for rhinos looks bright. But international cooperation on trade policies, strong law enforcement in range and consumer states, and novel solutions to curb demand appear to all be part of the near term mix of conservation actions.
Side photo by Peter Chadwick via ARKive of a white rhino (Ceratotherium simum).