of southwestern Louisiana and southeastern Texas. The study found red wolf ancestry in the coyote genomes which increases up to 60% in a westward gradient. This was due to introgression from the remnant red wolf population over the past 100 years. The study proposes that coyotes expanded into the gulf region and admixed with red wolves prior to the red wolf going extinct in the wild due to loss of habitat and persecution. In the past two decades the hybrid region has expanded. The study presented the genetic evidence that the red wolf is a separate species, based on the structure of one of the loci of its X-chromosome which is accepted as a marker for distinct species. As such, the study suggested that the introgressed red wolf ancestry could be de-introgressed back as a basis for breeding further red wolves from the hybrids. Pre-dates the coyote in North America In 2021, a study of mitochondrial genomes sourced from specimens dated before the 20th century revealed that red wolves could be found across North America. With the arrival of the gray wolf between 80,000–60,000 years ago, the red wolf's range shrank to the eastern forests and California, and the coyote replaced the red wolf mid-continent between 60,000–30,000 years ago. The coyote expanded into California at the beginning of the Holocene era 12,000–10,000 years ago and admixed with the red wolf, phenotypically replacing them. The study proposes that the red wolf may pre-date the coyote in North America. Explanatory footnotes References Further reading External links Red wolf, U.S. Fish and Wildlife Service Mammals described in 1851 Mammals of the United States Canid hybrids Controversial mammal taxa Wolves Wolves in the United States ESA endangered species Taxa named by John James Audubon Taxa named by John Bachman Critically endangered fauna of the United States