Black Rhinos, Horns Cut Off, Lose Some of Their Gusto


Black rhinos, a critically endangered species with a remaining population of only 5,500 to 6,000 individuals, face a more precarious situation than their larger counterparts, the white rhinos. In South Africa, which is home to 36 percent of the black rhino population, researchers led by Ms. Duthé examined 15 years of data tracking 368 of these animals across 10 wildlife reserves. While none of the black rhinos in the study had been dehorned prior to 2013, by 2020, 63 percent had undergone the procedure.

The study revealed that dehorning did not increase the risk of non-poaching-related deaths among the rhinos. However, dehorned individuals experienced a significant reduction in their home ranges, averaging a 45.5 percent decrease, although the extent varied among different rhinos. For instance, Hamba Njalo, a male, lost 27 percent of his territory, leaving him with 9.25 square miles, while Xosha, another male, saw an 82 percent reduction, leaving him with just under 3 square miles.

Additionally, dehorned rhinos were 37 percent less likely to engage in social interactions, particularly among male individuals. These findings shed light on the consequences of dehorning on black rhinos’ behavior and habitat utilization.

“The study is robust and good science, with long-term data and a large set of observations,” said Sam Ferreira, a large-mammal ecologist at the International Union for Conservation of Nature’s African Rhino Specialist Group, who was not involved in the research. “The results highlight important unintended consequences when seeking to deal with indirect approaches such as dehorning to address societal pressures on rhinos,” including poaching.

Rhino poaching has subsided from its peak in 2015, when 1,349 animals were killed out of a total African white and black rhino population of around 22,100. But the situation today remains “really critical and urgent,” Ms. Duthé said, with more than 548 rhinos poached across Africa last year.


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