The coyote, scientifically known as Canis latrans, is one of North America’s most adaptable and widespread canids, typically displaying a coat of gray, tan, or reddish-brown fur. While the vast majority of these animals conform to this standard coloration, a far less common variation exists: the black coyote. This distinct morph is a member of the same species that exhibits an unusually dark, often completely black, coat.
The Mechanism of Black Fur
The black coloration is caused by the biological process known as melanism, which is the opposite of albinism. This condition results from an overabundance of the dark pigment called eumelanin in the fur and skin. The genetic mechanism responsible for this color change in coyotes is tied to a specific area of the genome known as the K locus.
The gene at this locus encodes a beta-defensin protein that acts as a signaling molecule to regulate pigment production. A dominant mutation in this gene causes melanocytes, the cells that produce pigment, to switch almost entirely to producing eumelanin. This genetic switch overrides the normal coloration process, resulting in the dense, dark fur of the melanistic coyote.
Prevalence and Geographic Distribution
Black coyotes are rare across North America, typically making up less than 1% to around 5.7% of the total population. The frequency of this trait varies significantly by region. In many western states, a black coyote sighting is unusual, reflecting the low frequency of the responsible gene in those populations.
The highest concentrations of melanistic coyotes are found in the southeastern United States, particularly in states like Georgia, Tennessee, and North Carolina. In these areas, the percentage of black individuals can reach up to 10% of the local population. This regional difference is often explained by Gloger’s Rule, which suggests that darker animals are more common in warm, humid environments with dense vegetation. The dark coat may offer a survival benefit in the shadier, high-canopy habitats found in the Southeast, providing better camouflage during hunts.
Origin of the Melanism Gene
The melanism gene present in the coyote population did not originate within the species itself. Scientific consensus points to the trait being acquired through historic hybridization events with other canids. The genetic marker responsible for the black coat, the K locus mutation, is believed to have first arisen in domestic dogs.
The mutation was passed to wild canids, likely through interbreeding between domestic dogs and gray wolves or red wolves. Coyotes acquired the trait through hybridization with these wolf species as they expanded their range eastward in the 20th century. For example, in the Southeast, coyotes interbred with the native red wolf, a species where melanism was common. This genetic introgression introduced the black coat color gene into the coyote gene pool, allowing the trait to persist and spread regionally.