Dehorned Black Rhinos Have Much Smaller Home Ranges

20 Jun 2023

In South Africa and Namibia, rhinos often have their horns removed so that poachers do not find it worthwhile to hunt them. But many conservationists and researchers criticise the measure as harmful to the animals concerned. A study published this week provides them with new ammunition.

It states that dehorned rhinos have significantly smaller home ranges and less social interactions than their horned counterparts. The study was conducted by 14 researchers and experts from Switzerland and South Africa. They had studied the effects of dehorning on the behaviour and ecology of African black rhinos (Diceros bicornis).

According to their own information, they took into account data from more than 15 years of black rhino monitoring in ten game reserves in South Africa - with more than 24,000 sightings of 368 animals (see article in the scientific journal Proceedings of the National Academy of Sciences (PNAS) by Vanessa Duthé et al: "Reductions in home-range size and social interactions among dehorned black rhinoceroses (Diceros bicornis)").

The research team came to the conclusion that the habitat of dehorned animals is reduced by an average of 11.7 square kilometres compared to horned animals. This

corresponds to 45.5%. The dehorned rhinos were also 37% less likely to participate in social contact. So the horn seems to play an important role in interactions of rhinos.

Namibia has removed the horn from more than 900 rhinos since 2018. However, this is not a hundred percent protection against poaching. It happens that poachers kill dehorned rhinos because even the stump of the horn seems valuable enough to them. Critics also point to the stress for the animals and the high costs. Since the horn grows back, dehorning has to be repeated every two years.

More background on the pros and cons of dehorning rhinos can be found in an article by the organisation Save The Rhino International and a detailed Facebook post by Wildlife Vets Namibia.

 

 

Sven-Eric Stender