By Sara Gilane
Melanistic coyotes, also called black coyotes, are unique animals that only make up 5.7% of the coyote population. Their dark coloring comes from a number of factors. One factor is the overproduction of eumelanin, the type of melanin that controls brown and black pigments. Interestingly, this genetic mutation did not arise in coyotes until the 20th century, whereas melanism in North American gray wolves arose roughly 12,000 years ago, when they first migrated into North America from Asia.
Environmental Influences
Genetics are not the only cause of dark coloring in coyotes. Environmental influences can also affect gene expression. Researchers have tried for years to to explain why certain habitats produce specific coloring in wolves and coyotes that differ from other parts of their range. One of the most well-known theories is Gloger’s Rule, which states that in warm-blooded animals, heavily pigmented forms tend to be found in warm, humid environments, typically closer to the equator. This is because these climates promote dense vegetation, resulting in shadier environments.
The First Black Coyotes
Before their colonization of eastern North America, melanism in coyotes did not exist. Research indicates that eastern coyotes picked up the trait from interbreeding with red wolves which commonly exhibited the melanistic trait.
The eradication of the red wolf was key to the coyote’s colonization of eastern North America. Government-sponsored eradication campaigns wiped out red wolves in central and eastern areas of Oklahoma and Texas, southern Missouri and Arkansas by the 1940s, and most of Louisiana by the 1950s. Red wolves along the Tensas and Atchafalaya rivers of eastern Louisiana were snuffed out during the 1960s, leaving the last populations of wolves in southeastern Texas and southwestern Louisiana. The loss of the red wolf along the Mississippi River Basin and Gulf Coast regions opened a path into eastern North America for the coyote. It was also along this route that black coyotes were first documented by Arthur Halloran of the U.S. Fish and Wildlife Service (USFWS) in the ’50s in Oklahoma as coyotes replaced the red wolf.
By the 1970s, the remaining 100 to 200 red wolves left were spread out along the coastal region of southeast Texas and southwest Louisiana. The USFWS created the Red Wolf Recovery Program in 1973, following the passage of the Endangered Species Act, to prevent their complete extinction. The USFWS captured 17 red wolves to re-establish the population in a captive breeding program. Only russet-colored wolves were captured, and the melanistic red wolf had been eradicated. However, the melanistic wolves had already passed on their trait to coyotes. Coyotes spread the melanistic genes as they expanded their range.
Melanism in Coyotes Today
Today, melanism is predominately found in coyote populations that replaced red wolves in the Southeast. The more common “gray” coyotes have coats made up of brown, gray, black and white hair. The black coyote, on the other hand, has a smokey black or striking black coat with white patches on its chest and feet. Other than their coloration, black and gray coyotes exhibit no other physical differences, but do differ in habitat preferences and behavior.
In a radio-collared study led by Jazmin “Sunny” Murphy and Dr. Joey Hinton, they found the black coyote’s home range was 1.6 times larger than that of a gray coyote. Black coyotes also showed a preference for areas with canopy, shade and wetland. Furthermore, melanistic coyotes have an 83% survival rate versus 64% for gray coyotes. Their higher survival rate is most likely due to their ability to hide from hunters thanks to their black coats and preference for dark environments. This is one reason why researchers believe melanistic ‘yotes keep this trait. Their coloration does not seem to help them with killing prey, however.