Mammal Monday – Wait … There’s Only One Kind of Wolf?

Throughout the world, there are two main species of wolves: the red wolf, Canis lupus, and the gray wolf, Canis rufus. There is also a smaller species that lives in the Ethiopian highlands know as the Canis simensis. Wolves are a part of the Canis genus, a family that has thirty-five species. Until recently, it was thought that in North America there were eight species of the canid family, including gray wolves, red wolves, eastern wolves, coyotes, red foxes, gray foxes, kit foxes, and arctic foxes.  However, recent studies in the DNA of wolves throughout North America argue that the gray wolf is the only canid of wolf present on the continent.

Now, how could there only be one species of wolf on the vast continent of North America? While the gray wolf may be a single species, it has many subspecies including the Arctic wolf, northwestern wolf, Great Plains wolf, and Mexican wolf. But still, these numbers seem small in comparison to the size of the land that the species inhabits. The reason the gray wolf is the only wolf in North America is that red wolves and eastern wolves, previously regarded as separate species, have been proven to be hybrids of gray wolves and coyotes.

The study done to procure these claims sequenced the whole genomes of 28 canids, in which gray wolves, red wolves, eastern wolves, and coyotes were involved.  The study showed that gray wolves and coyotes have genetic similarities, including a common ancestor in Eurasia 50,000 years ago.  Along with this, the DNA results revealed that red wolves and eastern wolves were genetic hybrids, mistaken as separate species because of their distinctive appearances. Red wolves bare resemblance to coyotes genetically, making an even greater distinction between the red and eastern wolf, which correlates to the misunderstanding of the differentiation between the two “species”. Interestingly, the straying of genetic variation among wolves was partly due to humans and how we pushed gray wolves out of their habitats. As they were pushed out of their land, the red wolves were forced to reproduce with hybrids and coyotes.  Over time, these wolves began to differ genetically by greater amounts until there was a common misconception as to how many species inhabited North America.

The author of the study, Robert Wayne, a professor of UCLA, states “the recently defined eastern wolf is just a gray wolf and coyote mix, with about 75% of its genome assigned to the gray wolf.” The study also showed that red wolves are about 75% coyote. This shows that the while there may be significant genetic differences between the wolves, they still fall under the category of gray wolf.

Along in the study, the genomes of certain species were analyzed in a controlled genetic environment: twelve pure gray wolves from an area with no coyotes, three coyotes from an area with no gray wolves, and six eastern wolves and three red wolves. With this insurance of no hybridization in the genes, Wayne found nothing in the species genetics that did not correlate with coyotes or gray wolves, suggesting there is no genetic variations that substantiate the previous belief that eastern or red wolves are their own species.

In Unit 1, our class began learning the basics of biology. We learned that a genome is the entire  “library” of genetic instructions that an organism inherits. This specific study shows the complexity and vastness of such genetic material, by showing how both small and large genetic alterations can define a certain species. We then studied the classification of life through broad categories such as domain and kingdom, and then narrowed the classification more in categories such as genus and species. This study shows the complexity of life on earth and how it connects to the learning we have done in class by showing how diverse life is in a single species, and how the many genes and endless genetic variations connect and can prove commonality between specific organisms.

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Biology Teacher

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