Black horse

Not mythological in the provided sources. The black coat color is explained genetically: the Extension (E) and Agouti genes control presence and distribution of black pigment. The functional dominant allele of Extension (E) permits production of black pigment in hair; without it (ee) the coat is some shade of red. Breeds cited with commonly occurring black individuals include Friesian, Murgese, Merens/Ariegeois, Menorquín, Fell pony, Dales pony, Ostfriesen and Alt-Oldenburger, Kladruber, and Groningen.

A true black horse has an entirely black hair coat, black skin, and dark brown eyes. White markings, when present, reveal pink skin beneath the white hair. Black foals are frequently born mousey gray and may show temporary primitive markings that typically disappear as the adult black coat develops. Sun-bleaching from exposure and sweat can cause a black coat to take a rusty or brownish tinge, often most evident in mane and tail; fine hairs around eyes, muzzle, and genitalia often retain true black pigmentation and are used by horsepeople to confirm black coloration.

The sources provide no supernatural abilities. Descriptions concern genetics, phenotype identification, and breed distribution. Practical implications include potential visual confusion with dark bay or seal brown horses due to sun-bleaching or similar shades; genetic testing of Extension and Agouti alleles is the biological method to determine underlying black pigmentation potential.