Horn Rot in Chamois: Hunters Joining the Fight through Citizens Science

The first time I heard about ‘horn rot’, I was sitting in a lecture hall in France back in 2018, attending a mandatory course to get my chamois hunting authorisation. What struck me most was when the lecturer admitted that nobody really knew what caused this strange condition affecting these magnificent alpine animals. 

It wasn't until my first hunting trip to New Zealand that I actually saw horn rot with my own eyes. Local hunters shared photos of chamois they'd harvested, showing obvious, sometimes severe damage to their horns. What I initially thought was a European curiosity had found its way to the other side of the world. 

A hunter's obsession becomes science 

My fascination with mountain game, particularly Himalayan tahr, led me to spend two full years hunting and studying these creatures in their adopted New Zealand habitat. I wanted to understand everything about these animals, from their daily habits to their health challenges. 

This passion caught the attention of professors at the University of Torino's Veterinary Medicine department. Together, we launched a citizen science project studying ‘pink eye’ disease in both tahr and chamois populations across New Zealand. Working with the NZ Tahr Foundation, we asked hunters to report sightings or harvests of animals showing signs of pink eye infection. 

Between January 2022 and May 2023, we received 50 reports through our online system - 37 for tahr and 13 for chamois. Something unexpected emerged from these submissions - many of the chamois photos not only showed pink eye but also significant horn rot damage. 

West Coast mystery 

During countless conversations with Kiwi hunters, I learned that horn rot is particularly prevalent among chamois populations along New Zealand's West Coast. Two years ago, I returned to the country and joined a professional hunter on a tahr culling operation. He showed me several chamois skulls displaying clear horn rot damage, giving me my first close-up look at this mysterious condition. 

Curious for more information, I visited Christchurch Central Library and discovered D. Bruce Banwell's book ‘The Alpine Chamois’. Inside was a detailed report from 2011 describing the examination of a specimen provided by Marcus Pinney from South Westland: 

"A defect in the keratinised layer was evident grossly on the anterior aspect at the base of both horns... The keratinised layers at the base of the horn were separated in some areas by the presence of basophilic granular material with features of bacteria and larger oval structures resembling yeasts. Occasional structures resembling fungal hyphae were also present... Although there appeared to be a mixture of bacteria and fungi in the keratinised layers at the base of the horns, it was not clear from these sections whether the organisms were primary or secondary." 

Despite this analysis, the mystery remains unsolved - no definitive research has determined whether bacterial or fungal agents are causing this horn degeneration. 

From New Zealand to Europe and back 

Back in France, I shared my findings with colleagues, and we began asking hunters and wildlife managers throughout France and Italy about similar cases. Through social media, I connected with a hunter who had posted photos of European chamois with identical horn damage to what I'd observed in New Zealand. 

This revelation sparked an idea: What if we applied the same citizen science model we'd used for the pink eye study to investigate horn rot internationally? 

The International Horn Rot Project 

In January, the Italian delegation of the International Council for Game and Wildlife Conservation (CIC) launched its citizen science Horn Project. A few months later, the Association des Chasseurs de Grand Gibier in France, joined the initiative. Now, the New Zealand Deerstalkers Association (NZDA) is preparing to participate, and hunters will soon receive instructions on how to contribute to the online survey. 

This represents an extraordinary opportunity for hunters across three different countries to participate in genuine scientific research. It also highlights the critical role hunters play in monitoring and detecting changes in wildlife populations and their health status. 

What exactly Is horn rot?