Hybridization | Newenglandwolves

Are "coywolves" a real thing?

After the extirpation of wolves from New England, Western coyotes (Canis latrans) moved into the region and spread as a result of minimal competition and an abundance of prey. During their spread, they came into contact with remnant populations of Eastern wolves (Canis lupus lyacon) in Ontario, which are thought to be a separate species closely related to red wolves (Canis rufus), but could potentially be a sub-species of gray wolves as well. (9, 15, 41) From this admixture of coyotes and wolves, came the hybrid "Eastern coyote" (Canis latrans x lyacon), which is larger than its Western relative, due to its wolf ancestry or the larger prey available to it in the now apex-predator-less Northeast. (14,41) In fact, the larger Eastern coyotes have been able to partially fill the ecological niche that was left empty after they extirpation of wolves from New England, as they are able to hunt larger prey, although not quite at the same level of wolves, which are capbable of hunting moose (Alces alces). (2,14,41) A 2010 study Way et al., suggested that the Eastern coyote should be renamed a "Coywolf" to better reflect its hybrid status. (25,41) The idea of the "Coydog" (referring to a coyote-dog hybrid) is also common in New England, but the Way et al. study found no evidence of either domestic dog (Canis lupus familiaris) or gray wolf (Canis lupus) mitochondrial DNA in Eastern coyotes. (41)

CreditL Tom Koerner/ USFWS

Image of a Western coyote (Canis latrans)

Conflicting Theories of Wolf Ancestry

There is a lot of debate over whether or not the Eastern wolf (Canis lupus lyacon) is its own species, a sub-species of gray wolf, or the same species as the red wolf (Canis rufus).
The Eastern wolf is thought to be the speices that once inhabited New England, although it has recently been suggested that the historical wolves of New England were actually a seperate species altogether. (9)
A 2016 study by vonHoldt et al., suggested that the Eastern and red wolves are already highly admixed with gray wolves and coyotes. (40)
A 2001 study by Fascione, et al., hypothesized that the Eastern wolf is the same species as the red wolf, and that coyotes are more closely related to red and Eastern wolves than to gray wolves, which explains the propensity for interbreeding between the species. (9)
While there is a lot of debate over which groups of wolves are their own species versus sub-species versus hybrids, it is clear that a lot of interbreeding has occured between the candids in the Northeast, resulting in the "canis soupus" referred to in the Fascione study. (9)

Image of coyote-wolf hybrids, sometimes called "coywolves" (Canis latrans x lyacon)

Photo Credit: L. David Mech, Bruce W. Christensen, Cheryl S. Asa , Margaret Callahan, Julie K. Young / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

A Threat to Conservation

The hybridization of gray wolves, coyotes, different sub-species/species of wolves makes the goal of conserving wolf populations somewhat difficult. Hybrids are difficult to classify, and, along with the many sub-species of gray wolves, wolf hybrids make it difficult to categorize wolf species, which can create issues with policy-making and conservation plans.

Issues with the ESA

The ESA doesn't recognize hybrids, only distinct species or occasionally sub-species, which creates issues with the complicated listing and delisting process described in the ESA section on the General Information Page. The difficulties in classifying wolf species and sub-species was part of why the USFWS's first delisting proposal was shut-down, and it could cause issues for the Service in the future. (40)

Potential Issues for Recovery

If Eastern wolves return to New England, it is likely that the few individuals that recolonize will hybridize with the abundant Eastern coyote population, which could mean that any established populations would be more hybrid than "wolf". There has been discussion of reintroducing gray wolves from the west rather than Eastern wolves to New England as they may be less likely to hybridize, but they may not be the wolf species that was historically present in the New England area. (9, 45)

Credit: Bud Hamm/USFWS

Image of a Gray Wolf (Canis lupus)

Credit: Washington Department of Fish and Wildlife / Public domain