研究發現，黑色皮毛的灰狼基因具有一種免疫力，能夠更有效抵抗犬瘟熱病毒。黑狼於犬瘟熱爆發較多的地區更為常見。黑色皮毛亦可讓同類識別牠們具有這種特有基因，有助繁殖出有抗體的後代。科學家認為這種突變是在 1700 年代從馴養的狗傳到灰狼群的。
Research discovered wolves with black fur have immunity in their genes and can survive canine distemper virus (CDV) better. black wolves are more common in areas where more CDV outbreaks occur. The black coat can also allow them to identify wolves with that gene and have a better chance to produce disease-resistant offspring. This mutation is believed to be introduced to the wolves from domesticated dogs back in the 1700s.
