Coywolf

A coywolf is a hybrid animal that comes from the mixing of different species. These animals are descendants of coyotes, eastern wolves, gray wolves, and domestic dogs. All of these animals belong to the genus Canis. Because they all possess 78 chromosomes, they are able to interbreed. This genetic compatibility allows different species to pass traits to their offspring. This mixing creates complex animals that help scientists study how species change over time.

The physical traits of a coywolf depend on its specific parentage. Most hybrids are larger than a coyote but smaller than a wolf. Their behaviors are often intermediate between their parent species. For example, hybrids of eastern wolves and coyotes form cooperative social groups. These groups are generally less aggressive when playing together compared to pure coyotes. Their vocalizations are also unique. A howl might begin with a deep, strong sound like a gray wolf. It then transitions into a high-pitched yip similar to a coyote.

One major type of hybrid is the eastern coyote. These animals range from New England through the eastern United States into Canadian provinces. They exist in a large mammalian hybrid zone in the Great Lakes region. This zone was created when coyotes and wolves hybridized. For 400 years, extensive hunting caused gray wolf populations to decline. This reduction in wolves meant there were fewer suitable mates for them. As a result, coyote genes began swamping into the eastern wolf population.

Scientists have used genomic studies to understand these complex gene pools. In 2014, a team led by Monzón analyzed tissue from 425 eastern coyotes. They found that many are "four-in-one" hybrids. The domestic dog allele averages about 10% of the eastern coyote's gene pool. A cluster of eastern and western gray wolves contributes about 26%. The remaining 64% of the DNA matches mostly with coyotes. This suggests multiple swarms of genetic exchange occurred between coyotes, feral dogs, and two wolf populations.

The environment plays a role in which genes become more common. Hybrids living in areas with high white-tailed deer density often have more wolf genes. In contrast, those in urban environments often have more coyote genes. The presence of domestic dog genes may help these hybrids adapt to human-developed areas. This adaptability allows them to survive in cities more easily than pure wolves. The genetic makeup of these animals shifts based on where they live.

There is significant scientific debate regarding the classification of these animals. Some researchers argue that red wolves and eastern wolves are distinct species. However, a 2011 study of 48,000 single nucleotide polymorphisms suggested they are hybrid species. That study claimed red wolves are 76% coyote and 20% gray wolf. It also suggested eastern wolves are 58% gray wolf and 42% coyote. Other scientists criticized this study for using insufficient samples. They argued the results were based on modern specimens rather than historical ones.

Recent research continues to provide new perspectives on canid history. A 2016 whole-genome DNA study suggested all North American canids diverged from a common ancestor 6,000 to 117,000 years ago. This study identified the red and eastern wolves as admixtures of coyotes and gray wolves. However, a 2017 study challenged these findings. That group argued that the red and eastern wolves show high evolutionary distinctness. They believe these animals should remain classified as distinct North American taxa. The study of these hybrids remains a central part of understanding evolutionary biology.