Researchers confirm rare melanism in Brazilian marsh deer

Researchers have documented the first scientific instances of melanism in the marsh deer (Blastocerus dichotomus), a rare genetic condition that causes excessive melanin production, resulting in much darker fur. While local legends in the Pantanal region have long spoken of ‘black deer,’ these findings provide the first formal biological confirmation of the phenomenon.

The study, published in the journal ‘Notas sobre Mamíferos Sudamericanos’ by researchers from Onçafari and Embrapa Pantanal, identified two distinct populations: one in the Pantanal and another in the Cerrado. The first recorded instance occurred in February 2021, when an adult female was photographed at Caiman Pantanal in Mato Grosso do Sul.

Experts suggest the presence of melanism in the Cerrado, specifically within the Grande Sertão Veredas National Park, may serve as a conservation warning. Researchers believe that population isolation caused by habitat degradation and hunting pressure could be increasing the frequency of such genetic mutations, potentially indicating risks to the species' overall genetic health.