Liliana Cortés Ortiz coauthored a Consensus Study Report for the National Academies of Sciences, Engineering, and Medicine’s Division on Earth and Life Studies titled “Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf.” Cortés Ortiz is a research associate professor in the University of Michigan Department of Ecology and Evolutionary Biology.

“Taxonomy – the scientific study of biological classification – enables scientists to name and group living organisms,” states the report. “However, because species are dynamic and not fixed entities, taxonomic designations are often debated…

“This is the current case with the Mexican gray wolf (Canis lupus baileyi) and the red wolf (Canis rufus)…

Cover of the report, "Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf."

“At any given time, different populations can be in different stages in the process of species formation or dissolution. In many cases, hybridization (i.e., mating with other species and producing offspring) may be introducing genes from one species to another.

“In 2018, Congress directed the U.S. Fish and Wildlife Service to obtain an independent assessment of the taxonomic status of the red wolf and the Mexican gray wolf. Currently, FWS considers the red wolf a valid taxonomic species and the Mexican gray wolf a valid taxonomic subspecies. Both wolves are listed as endangered under the U.S. Endangered Species Act. This report assesses the taxonomic status of the Mexican gray wolf and the red wolf based on an evaluation of multiple types of data, including morphological and paleontological evidence, evidence of genetic and genomic distinctiveness, and ecological and behavioral evidence.”

The synthesis of findings and conclusion in the report states, “The most plausible option from the synthesis of findings about the taxonomic status of the red wolf is that it is a distinct species of wolf (Canis rufus). The available evidence suggests that the most appropriate taxonomic designation for red wolves is as a distinct species that possibly has historical admixture.”

In addition, “Mexican gray wolves are distinct from other North American gray wolves morphologically, paleontologically, genetically, genomically, behaviorally, and ecologically. Thus, the Mexican gray wolf is a valid taxonomic subspecies of the gray wolf, Canis lupus, with its current classification of Canis lupus baileyi.

Mexican gray wolf. Image: US Fish and Wildlife Service from flickr

“The taxonomy of North American wolves is difficult to disentangle,” said Cortés Ortiz. “On the one hand, the evolutionary history of this group includes a relatively recent radiation, and likely, several instances of genetic admixture among differentiating lineages. On the other hand, habitat modification and direct human intervention dramatically reduced the size of natural populations of both Mexican wolves and red wolves, making it challenging to interpret evidence based on currently living animals and the few historical specimens available. The committee was composed of people with a broad range of expertise, including ecology and behavior, molecular evolution, morphology, population genetics, taxonomy, and systematics, who put their best effort to synthesize and analyze the wealth of information available for North American wolves. It was a great pleasure to be part of and work alongside this outstanding and diverse group of scientists.

“The task given to the committee specifically requested not to consider conservation implications of our decisions regarding the taxonomy of Mexican wolves and red wolves, so our conclusions are only based on available scientific evidence in regards to wolf taxonomy,” explained Cortés Ortiz.  

“In my opinion, decisions about wolf conservation will require a broader range of expertise and perspectives than was represented by the committee. I hope that USFWS will take the report into consideration along with conservation-focused evidence provided by USFWS personnel and other organizations to guide their efforts on the protection of Mexican wolves and red wolves.”

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compiled by Gail Kuhnlein