The eastern wolf, also known as Eastern Canadian wolf or Eastern Canadian red wolf, may be a subspecies of gray wolf (Canis lupus lycaon), a distinct species of canid (Canis lycaon) or a hybrid species (Canis lupus X Canis latrans) native to the eastern part of North America since the Pleistocene era. It seems to be closely related to the red wolf. Some populations may contain instances of hybridization with coyotes, known as coywolves.
Eastern wolf was recently recognized as a potentially distinct species, but closely related to red wolf. Some authors disagree and the status as a distinct species is not official. Now, many international and government organizations carry out scientific research for their taxonomy and genetics to answer this question, as well as researching their ecology and influence on the ecosystem.
The eastern wolf is smaller than the gray wolf and has a gray-reddish coat with black hairs covering the back and sides of the thorax. The mtDNA analysis confirms that eastern wolf belonged to an ancient form of primitive wolf (with red wolf) originating some 750,000 years ago in the eastern part of North America (Nowak 1979, 1992). This distribution of haplotypes shows elements similar to the red wolf and probably is a part of this species. Red wolf populations were extirpated from the wild in the southeastern United States, were reintroduced to the wild in recent decades and are now critically endangered.
On March 31, 2010, a presentation by Ontario Ministry of Natural Resources research scientist Brent Patterson outlined key findings about the eastern wolf (and coyotes): Most coyotes in Eastern Ontario are wolf-coyote hybrids; wolves in Algonquin Park are, in general, not inter-breeding with coyotes; and the buffer zone around Algonquin Park is a great success with mortality rates down and populations remaining stable.
Proponents of distinct species designation believe that the Eastern Canadian wolf is just the remnant northern range of a once continuous range of a native canid – the eastern wolf (Eastern Canadian wolf and red wolf). The pre-Columbian range was thought to include U.S. states east of the Mississippi and south of the Canadian Shield-St. Lawrence corridor.
Unlike the gray wolf, the eastern wolf in Algonquin Park has never been recorded with an all-black or all-white coat (wolf research in Al. P. cited 2008). Eastern wolf mainly exist in Algonquin Park in Canada-USA border. Type Algonquin is a largely pure genetic population of Eastern wolf while type-Ontario is hybrid with gray wolf (possible with C. l. nubilus or C. l. griseoalbus ad etc.) (Wilson et al. 2000). Mech and Frenzel (1971) suggest that the northeastern Minnesota timber wolves are assigned to C. l. lycaon but are found in an area within 150 km of the range of C. l nubilus as described by Goldman (1944).
The eastern wolf is smaller than the gray wolf. It has a pale grayish-brown pelt. The back and the sides are covered with long, black hairs. Behind the ears, there is a slight reddish color. These differences in attributes are thought to be a result of their red wolf ancestry. The eastern wolf is also skinnier than the gray wolf and has a more coyote-like appearance. This is because wolves and coyotes often mate and breed wolf/coyote hybrid pups in the park. The Canadian Parks and Wilderness Society states: "Hybridization with coyotes has historically been a precursor to the decline of Eastern wolf populations. The Committee on the Status of Wildlife in Canada (COSEWIC) has identified hybridization with coyotes as one of the major threats facing the Eastern wolf, and hybridization continues to pose a serious challenge to red wolf recovery efforts in North Carolina." Because the two animals looks so much alike, a ban on the hunting of Algonquin wolves and coyotes has been in place to make sure no accidental deaths occur.
Gray wolves will attack, kill or drive out coyotes if they find them, but recent studies by John and Mary Theberge suggest that males wolves possibly mate with and accept coyote females. John Theberge states that, because coyotes are smaller than wolves, that female wolves would be less likely to accept a smaller mate.
In May 2011, an analysis of red wolf, Eastern wolf, gray wolf, and dog genomes revealed that the red wolf was 76–80 percent coyote and only 20–24 percent gray wolf while the Eastern wolf is 58% gray wolf and 42% coyote, suggesting that the red wolf is actually much more coyote in origin than the Eastern wolf.  This study analyzed 48,000 SNP concluded that both the Eastern wolves and red wolves are hybrids between gray wolves and coyotes and found no evidence for a unique Eastern wolf or red wolf species. 
The eastern wolf mainly occupies the area in and around Algonquin Provincial Park in Ontario, and also ventures into adjacent parts of Quebec, Canada. It is present in New York state. It also may be present in Minnesota and Manitoba. In the past, this species might have ranged south into the United States, but after the arrival of Europeans, these wolves were heavily persecuted and became extirpated from the United States. In Canada, exact numbers of Eastern Canadian wolves are unknown.
In Algonquin wolves often travel outside the park boundaries, and enter farm country where some are killed. "Of all the wolf deaths recorded from 1988 to 1999, a minimum of 66% was caused by humans. Shooting and snaring outside park boundaries were the leading causes of death for wolves radio-collared in Algonquin Park". One wolf that was radio-collared in July 1992 was located in October in Gatineau Park (north of Ottawa), which is 170 km from Algonquin Park. By mid-December it had made its way back to Algonquin and then, in March 1993, this wolf's severed head was found nailed to a telephone pole in Round Lake.
The eastern wolf preys on white-tailed deer, moose, lagomorphs, and rodents including beaver, muskrat, and mice. Studies in Algonquin Provincial Park showed that three species accounted for 99% of the wolves' diet: moose (some of which is scavenged), white-tailed deer, and beaver (ca. 33% each). The wolves tend to prey more frequently on beaver in the summer, and on white-tailed deer in the winter.
- Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Eastern Wolf. Canadian Parks and Wilderness Society
- Grewal, Sonya K.; Wilson, Paul.J.; Kung, Tabitha K.; Shami, Karmi; Theberge, Mary T.; Theberge, John B.; White, Bradley N. (2004). "A Genetic Assessment of the Eastern Wolf (Canis Lycaon) in Algonquin Provincial Park". Journal of Mammalogy 85 (4): 625. doi:10.1644/1545-1542(2004)085<0625:AGAOTE>2.0.CO;2.
- Kyle, C.J.; Johnson, A.R.; Patterson, B.R.; Wilson, P.J.; Shami, K.; Grewal, S.K.; White, B.N. (2006). "Genetic nature of eastern wolves: Past, present and future". Conservation Genetics 7 (2): 273. doi:10.1007/s10592-006-9130-0.
- Bradley White, Paul Wilson, Aria Johnson, Sonya Grewal and Karmi Shami: Status of the eastern wolf (Canis lycaon). Natural Resources DNA Profiling and Forensic Centre, Trent University, Peterborough, Ontario (2001)
- Lehman, Niles; Eisenhawer, Andrew; Hansen, Kimberly; Mech, L. David; Peterson, Rolf O.; Gogan, Peter J. P.; Wayne, Robert K. (1991). "Introgression of coyote mitochondrial DNA into sympatric North American gray wolf populations". Evolution 45 (1): 104–119. doi:10.2307/2409486. JSTOR 2409486.
- Aria Johnson & Brad N. White, 2003
- Theberge 1998, CBSG 2000
- Banfield, A.W.F. 1974. The Mammals of Canada. University of Toronto Press.
- Reid, F.A. 2006. Field Guide to the Mammals of North America north of Mexico. Fourth Edition. Houghton Mifflin. New York.