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While Texas Parks and Wildlife (TPWD) biologists were conducting wildlife surveys in the Trans-Pecos area, they spotted something extremely unusual: a melanistic mule deer.
According to the TPWD Trans-Pecos Wildlife District Facebook, it is difficult for biologists to quantify the number of mule deer with this condition. It is estimated to be around one in several million. A melanistic muley is even rarer than an albino or piebald mule deer (with white markings).
Melanism is a recessive genetic trait caused by mutations in the melanocortin 1 receptor (MC1R) gene. A 2020 study from Germany explains that the ratio and distribution of the pigments eumelanin and pheomelanin define the basic coloration of the hair and skin coat. The MC1R mutation increases the production of eumelanin to create a uniformly black or dark coat. While this condition will affect fur-covered creatures, it most often occurs in birds, like this turkey harvested in 2020.
Just east of the Trans-Pecos area is the Edwards Plateau Ecoregion. According to the National Deer Association, this is where the largest known concentration of melanistic whitetails exists. But melanism in muleys is an even rarer phenomenon, making this sighting truly one in a million.
Featured Image and Video via TPWD District 1 Biologists J. Etchart and J. Weaver.