When I think about it, the results of this study are pretty much common sense. If you remove a vital part of an animals defensive anatomy you are going to alter the mentality of that animal negatively. It is the same with declawing cats about which I know a hell of a lot! It changes the cat’s character. They bite more.
Scientists at the Université of Neuchâte in Switzerland working with institutions in South Africa conducted a study on rhino behavior before and after their horns were removed to protect them from poaching, a massive conservation problem in Africa.
Horns are made of keratin, the same material that our nails and hair is made of and yet millions of Asians believe it has some sort of magical medicinal benefit if consumed. It is 100% distilled mumbo-jumbo. Strong words but necessary words. My polite message to these Asians: Eating keratin does not improve your health!
The scientists collated 24,000 sightings of 368 rhinos over 15 years; a big undertaking, to watch out for altered behaviour. They used GPS tracking after gluing a GPS transmitter to the stump of their removed horn. This provided continuous data over several months.
It should be said that as the horn regrows in less than 2 years, the risky process of removing it has to be repeated so this is a far from ideal MO.
Dehorning does improve conservation. Black rhino poaching decreased. More rhinos survived. And dehorning does not, it seems, harm the rhino’s survivability prospects.
However, dehorning did not impair survival and natural mortality did not increase with the percentage of dehorned rhinos going up. – the study
On the downside, the study found that dehorned black rhinos reduced their home range on average by 11.7 square kilometers. This is a huge 45.5 percent reduction in the area that they call home – their home range.
And they were 37 percent less likely to engage socially. The scientists concluded that dehorning made them feel more vulnerable and less social.
We conclude that dehorning black rhinos as an anti-poaching measure alters their behavioural ecology – study
Comment: it seems to have made them feel more anxious and less confident. Apparently male-to-male interactions fell off the most. This indicates a shift in the dominance/submission hierarchical social structure. The long-term effect is unknown at this time but it could affect population management and translocations according to the report in the Telegraph newspaper (the source of this article – thanks).
We think that rhinos avoid each other more and therefore are less likely to fight (in particular, male-male interactions) because they feel vulnerable without their main armament. But this remains to be evidenced.” – study author: Ms Duthe.
Comment: clearly removing the horn as a conservation MO has substantial downsides. I suspect that there will be a review of it.
Final comment: there is also an aesthetic aspect to dehorning. You lose the magnificent and unique appearance of this iconic species when you remove their defining piece of anatomy.
The study is published in the journal PNAS.
Also, rhino horn size is shrinking because of poaching: