The red wolf (Canis rufus, formerly Canis lupus rufus), also known as the Florida wolf or Mississipi Valley wolf is a canid native to the Southeastern United States. It is generally morphologically intermediate between the coyote and gray wolf, and is of a reddish, tawny color.
Originally distributed throughout the Southeastern US, the red wolf was nearly driven to extinction by the mid-1900s due to aggressive predator control programs, habitat destruction and extensive hybridization with coyotes. By the late 1960s, it occurred in small numbers in the Gulf Coast of western Louisiana and eastern Texas. 14 of these survivors were selected to be the founders of a captively bred population, which was established in the Point Defiance Zoo & Aquarium between 1974-1980. After a successful experimental relocation to Bulls Island off the coast of South Carolina in 1978, the red wolf was declared Extinct in the Wild in 1980 in order to proceed with restoration efforts. In 1987, the captive animals were released into North Carolina's Alligator River National Wildlife Refuge, with a second release taking place two years later in the Great Smoky Mountains National Park.
The red wolf's taxonomic status has been a subject of controversy. A 2011 genetic study indicated that it may be a hybrid species between gray wolves and coyotes. Re-analysis of this study coupled with a broader contextual analysis including behavioral, morphological and additional genetic information led to arguments that the red wolf is an independent species but has suffered from significant introgression of coyote genes likely due to decimation of red wolf packs with fragmentation of their social structure from hunting. A comprehensive review in October 2012 concluded that the red wolf is a distinct species which diverged from the coyote alongside the closely related eastern wolf 150,000-300,000 years ago.
The taxonomy of the red wolf has been debated since before efforts began in 1973 to save it from extinction. In 1971, Atkins and Dillon conducted a study on the brains of canids and confirmed the basal characteristics of the red wolf. Many studies throughout the 1970s focused on the morphology of the red wolf came to the conclusion that the red wolf is a distinct species. In 1980, a unique allele was found in Canis specimens from within the red wolf range, supporting the conclusion that the red wolf is a distinct species. Nevertheless, some in the scientific community considered it a subspecies of the gray wolf or a hybrid of the gray wolf and the coyote.
In 1992, the USFWS conducted an exhaustive review of the literature, including their own, and concluded that the red wolf is either a separate species unto itself or a subspecies of the gray wolf. Many agency reports, books and web pages list the red wolf as Canis rufus but genetic research re-opened the debate about the taxonomy of both the red wolf and Canada's eastern wolf (Canis lupus lycaon). Wilson et al. (2000) concluded that the eastern wolf and red wolf should be considered as sister taxa due to a shared common ancestor going back 150,000–300,000 years. In addition, Wilson et al. further stated that they should be recognized as distinct species from other North American canids, and not as subspecies of the gray wolf (Canis lupus). However, these conclusions were disputed, and MSW3 listed them both in 2005 as subspecies of the gray wolf.
In May 2011, an analysis of red wolf, Eastern wolf, gray wolf, and dog genomes suggested that the red wolf was 76–80 percent coyote and only 20–24 percent gray wolf, suggesting that the red wolf is actually much more coyote in origin than the Eastern wolf. This study analyzed 48,000 SNP and found no evidence for a unique Eastern wolf or red wolf species. However, X-Ray analysis of the 16 red wolf specimens used in the SNP study were later shown to be wolf-coyote hybrids via cranial morphometric analysis, rendering the finding that the red wolf was a gray wolf-coyote hybrid inaccurate. The U.S. Fish and Wildlife Service (USFWS) still considers the red wolf a valid species (Canis rufus) and plans to make no changes to its recovery program. In 2012, re-analysis of the 2011 SNP study argued that the original SNP study suffered from insufficient sampling and noted that gray wolves do not mate with coyotes. Another Y-chromosome genetic study in 2012 also argued that the eastern wolf and red wolf are not hybrids but rather are a distinct species from the gray wolf, although eastern and red wolves do intermix with coyotes. The same authors have argued that the 2011 SNP study finding that red wolves are not an independent species is flawed and that historical hunting and culling of wolves, leading to invasion of coyotes into eastern North America, has led to introgression of coyote mitochondrial and nuclear DNA into fragmented, decimated eastern wolf packs. They and other authors have postulated that large populations of eastern and red wolves with intact social/pack structures are less likely to interbreed with coyotes. The controversy over the red wolf's species status was the subject of a comprehensive review of the 2011 and 2012 genetics studies, which concluded that there are three separate species of wolf in North America, the red wolf, eastern wolf and gray wolf.
In a pair of 2012 reports, scientists critical of the May 2011 paper outlined three main points of criticism. First, the 2011 paper relied on mtDNA SNPs derived from boxer and poodle genomes and used these to extrapolate inference about genetic variation within wild canids across the globe. While it is true that many SNPs were examined, it remains unclear whether loci important to red wolf genetic variation were actually identified and analyzed (for example, nuclear DNA was not compared in the SNP analysis). Second, the study sampled modern red wolf specimens, and not historic red wolf specimens from prior to 1900 (when extensive hybridization with coyotes is known to have taken place), which obfuscates the reliability of the study's findings. This is important because using historic red wolf genetic material would have created a baseline genetic profile for the species against which to test the modern captive-bred specimens. (It is common knowledge that the captive-bred red wolves are likely slightly hybridized, but this is a separate issue from interpreting their species origin as due to hybridization.) Third, the authors lumped Eastern wolf specimens (which critics from Trent University warn are of unverified origin) with other Great Lakes wolf specimens, and did not test them separately, which again obfuscated any genetic differences that may have been present. The controversy over the eastern wolf's origins is not considered by the scientific community to be laid to rest, although it may be synonymous with the red wolf.
When considered as a full species, three subspecies of red wolf were originally recognized by Goldman; two of these subspecies are extinct. The Florida black wolf (Canis rufus floridanus) (Maine to Florida) has been extinct since 1930 and Gregory's wolf (Canis rufus gregoryi) (south-central United States) was declared functionally extinct in the wild by 1980. The Texas red wolf (Canis rufus rufus), the third surviving subspecies, was also functionally extinct in the wild by 1980, although that status was changed to "critically endangered" when captive-bred red wolves from Texas were reintroduced in eastern North Carolina in 1987. The current status of the "non-essential/experimental" population in North Carolina is "endangered" and the population numbers around 100 wild animals. The subspecies designations are essentially moot since two are extinct but the genetic evidence for the three subspecies appears to have been unconvincing anyway.
Fossil and historic record
Paleontological evidence has suggested an origin of the red wolf line 1–2 Ma, branching from a wolf-coyote ancestor, which itself appeared about 4.9 Ma. Between 150,000–300,000 years ago, the North American branch evolved into the red wolf, eastern wolf and the coyote. Another wolf-like branch migrated to Eurasia and evolved into the gray wolf, which later migrated to North America. It is thought that its original distribution included much of eastern North America, where red wolves were found from Maine south to Florida and in south central US westward to Texas. Records of bounty payments to Wappinger Indians in New York in the middle 18th century confirm its range at least that far north; it's possible that it could have extended as far as extreme eastern Canada.
Physical description and behavior
The red wolf's appearance is typical of the genus Canis, and is generally intermediate in size between the coyote and gray wolf, though some specimens may overlap in size with small gray wolves. Adults measure 136-160 cm in length, and weigh 40-90 lbs. Its pelage is typically more reddish and sparsely furred than the coyote's and gray wolf's, though melanistic individuals do occur. Its fur is generally tawny to grayish in color, with light markings around the lips and eyes. Like the eastern wolf, the red wolf has been compared by some authors to the greyhound in general form, owing to its relatively long and slender limbs. The ears are also proportionately larger than the coyote's and gray wolf's. The skull is typically narrow, with a long and slender rostrum, a small braincase and a well developed sagittal crest. Its cerebellum is unlike that of other Canis species, being closer in form to that of canids of the Vulpes and Urocyon genera, thus indicating that the red wolf is one of the more basal members of its genus.
The red wolf is more sociable than the coyote, but less so than the gray wolf. It mates in January-February, with an average of 6-7 pups being born in March, April and May. It is monogamous, with both parents participating the rearing of young. Denning sites include hollow tree trunks, along stream banks and the abandoned earths of other animals. By the age of six weeks, the pups distance themselves from the den, and reach full size at the age of one year, becoming sexually mature two years later.
Prior to its extinction in the wild, the red wolf's diet consisted of nutria, rabbits and rodents. In contrast, the red wolves from the restored population rely on white-tailed deer, raccoon, nutria and rabbits. It should be noted, however, that white-tailed deer were largely absent from the last wild refuge of red wolves on the Gulf Coast between Texas and Louisiana (where specimens were trapped from the last wild population for captive breeding), which likely accounts for the discrepancy in their dietary habits listed here. Historical accounts of wolves in the southeast by early explorers such as William Hilton, who sailed along the Cape Fear River in what is now North Carolina in 1644, also note that they ate deer.
Range and habitat
The originally-recognized red wolf range extended throughout the Southeast, from the Atlantic and Gulf Coasts, north to the Ohio River Valley and central Pennsylvania, and west to Central Texas and southeastern Missouri. But research into paleontological, archaeological and historical specimens of red wolves by Ronald Nowak expanded their known range to include land south of the Saint Lawrence River in Canada, along the eastern seaboard, and west to Missouri and mid-Illinois, terminating in the southern latitudes of Central Texas. Since 1987, red wolves have been released into northeastern North Carolina where they roam 1.7 million acres. These lands span five counties (Dare, Hyde, Tyrrell, Washington and Beaufort) and include three national wildlife refuges, a U.S. Air Force bombing range, and private land. The red wolf recovery program is unique for a large carnivore reintroduction in that more than half of the land used for reintroduction lies on private property. Approximately 680,000 acres (2,800 km2) are federal and state lands, and 1,002,000 acres (4,050 km2) are private lands. Beginning in 1991, red wolves were also released into the Great Smoky Mountains National Park in eastern Tennessee. However, due to exposure to environmental disease (parvovirus), parasites and competition (with coyotes as well as intraspecific aggression), the red wolf was unable to successfully establish a wild population in the park. Low prey density was also a problem, forcing the wolves to leave the park boundaries in pursuit of food in lower elevations. Other red wolves have been released on the coastal islands in Florida, Mississippi, and South Carolina as part of the captive breeding management plan. St. Vincent Island in Florida is currently the only active island propagation site.
Given their wide historical distribution, red wolves probably utilized a large suite of habitat types at one time. The last naturally occurring population utilized coastal prairie marshes, swamps and agricultural fields used to grow rice and cotton. However, this environment probably does not typify preferred red wolf habitat. There is evidence that the species was found in highest numbers in the once extensive bottom land river forests and swamps of the southeastern United States. Red wolves re-introduced into northeastern North Carolina have utilized habitat types ranging from agricultural lands to forest/wetland mosaics characterized by an over story of pine and an understory of evergreen shrubs. This suggests that red wolves are habitat generalists and can thrive in most settings where prey populations are adequate and persecution by humans is slight.
History and conservation
Discovery and persecution
Before the arrival of Europeans, the red wolf featured prominently in Cherokee mythology, where it is known as wa'ya (ᏩᏯ), said to be the companion of Kana'ti the hunter and father of the Aniwaya or Wolf Clan. Its reddish color was seen as symbolizing war, as well as all things sacred and beloved. Cherokees generally avoided killing red wolves, as it was believed that such an act would bring about the vengeance of the killed animals' pack-mates.
The red wolf was first described by William Bartram, who encountered it in Florida and wrote of it in his Travels (1791), noting that it was smaller and lighter in color than the gray wolves of Canada and Pennsylvania. John James Audubon was the first to describe the red wolf in detail, giving it the trinomial name of Canis lupus rufus in 1851. He described it as being more fox-like than the gray wolf, but retaining the same "sneaking, cowardly, yet ferocious disposition". Audubon also recounted that red wolves occasionally fed on the battlefield corpses of fallen soldiers during the Mexican–American War. The red wolf's full specific rank was first given by Edward Goldman in 1937, who examined a number of skulls and noted that the red wolf's skull and dentition differed from those of gray wolves, and closely approached those of coyotes. He wrote that by the time of writing, the species may have become extinct in the lower Sonoran zone, where it was heavily persecuted by ranchmen. Stanley P. Young noted in 1940 that the red wolf was still common in eastern Texas, where more than 800 had been caught in 1939, and further cast doubt over the prospect of fully exterminating them, due to their habit of living concealed in thickets. However, by 1962, red wolf sightings became increasingly rare, and few tracks or scats were found.
Captive breeding and reintroduction
Formal efforts backed by the U.S. Fish and Wildlife Service began to save the red wolf from extinction in 1973 when a captive breeding program was established at the Point Defiance Zoological Gardens, Tacoma, Washington. Four hundred animals were captured from southwestern Louisiana and southeastern Texas from 1973 to 1980 by the US Fish and Wildlife Service. Measurements, vocalization analyses, and skull X-rays were used to distinguish red wolves from coyotes and red wolf-coyote hybrids. Of the 400 animals captured, only 43 were believed to be red wolves and sent to the breeding facility. The first litters were produced in captivity in May 1977. Some of the pups were determined to be hybrids, and they and their parents were removed from the captive breeding program. Of the original 43 animals, only 17 were considered pure red wolves and since three were unable to breed, 14 became the breeding stock for the captive breeding program. These 14 were so closely related that they had the genetic effect of being only eight individuals.
In Dec. 1976, two wolves were released onto Cape Romain National Wildlife Refuge's Bulls Island in South Carolina with the intent of testing and honing reintroduction methods. They were not released with the intent of beginning a permanent population on the island. The first experimental trans location lasted for 11 days, during which a mated pair of red wolves were monitored day and night with remote telemetry. A second experimental trans location was tried in 1978 with a different mated pair, and they were allowed to remain on the island for close to nine months. After that, a larger project was executed in 1987 to reintroduce a permanent population of red wolves back to the wild in the Alligator River National Wildlife Refuge (ARNWR) on the eastern coast of North Carolina. Also in 1987, Bulls Island became the first island breeding site. Pups were raised on the island and relocated to North Carolina until 2005.
In September 1987, four male-female pairs of red wolves were released in Alligator River National Wildlife Refuge in northeastern North Carolina and designated as an experimental population. Since then, the experimental population has grown and the recovery area expanded to include four national wildlife refuges, a Department of Defense bombing range, state-owned lands, and private lands, encompassing about 1,700,000 acres (6,900 km2).
In 1989, the second island propagation project was initiated with release of a population on Horn Island off the Mississippi coast. This population was removed in 1998 because of a likelihood of encounters with humans. The third island propagation project introduced a population on St. Vincent Island, Florida offshore between Cape San Blas and Apalachicola, Florida in 1990, and in 1997 the fourth island propagation program introduced a population to Cape St. George Island, Florida south of Apalachicola, Florida.
In 1991, two pairs were reintroduced into the Great Smoky Mountains National Park, where the last known red wolf was killed in 1905. Despite some early success, the wolves were relocated to North Carolina in 1998, ending the effort to reintroduce the species to the Park.
In 2007, the US Fish and Wildlife Service estimated that there were 300 red wolves remaining in the world, with 207 of those in captivity.
According to the latest Red Wolf Recovery Program First Quarter Report (October–December 2010), the US Fish and Wildlife Service estimates that there are currently 110-130 red wolves in the Red Wolf Recovery Area in North Carolina, however, since not all of the newly bred in the wild red wolves have radio collars, they can only confirm a total of 70 "known" individuals, 26 packs, 11 breeding pairs, and 9 additional individuals not associated with a pack.
Interbreeding with the coyote has been recognized as a threat affecting the restoration of red wolves. Currently, adaptive management efforts are making progress in reducing the threat of coyotes to the red wolf population in northeastern North Carolina. Other threats, such as habitat fragmentation, disease, and anthropogenic mortality, are of concern in the restoration of red wolves. Efforts to reduce the threats are presently being explored.
- Kelly BT, Beyer A & Phillips MK (2008). Canis rufus. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 2008-10-23. Database entry includes justification for why this species is critically endangered.
- Audubon, J. and J.Bachman.1851.The quadrupeds of North America, Volume 2.New York, NY.p.334.
- Chambers SM, Fain SR, Fazio B, Amaral M (2012). "An account of the taxonomy of North American wolves from morphological and genetic analyses". North American Fauna 77: 1–67. doi:10.3996/nafa.77.0001. Retrieved 2013-07-02.
- 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.
- Glover, A. (1942), Extinct and vanishing mammals of the western hemisphere, with the marine species of all the oceans, American Committee for International Wild Life Protection, pp. 229-233.
- Reich, D.E., R.K. Wayne, and D.B. Goldstein. (1999) Genetic evidence for a recent origin by hybridization of red wolves. Molecular Ecology 8:139-144.
- Paradiso, J. L., and R. M. Nowak. 1972. Canis rufus. Mammalian Species 22:1–4
- Woodward, D. W. (1980), The Red Wolf, FWS
- Hendry, D. (2007), Red Wolf Restoration: A 20-Year Journey, International Wolf Center, vol. 17, no. 4
- VonHolt, BM; et al (12 May 2011). "A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids". Genome Res 21 (8): 1294–305. doi:10.1101/gr.116301.110. PMC 3149496. PMID 21566151.
- Linda Y. Rutledge, Paul J. Wilson, Cornelya F.C. Klütsch, Brent R. Patterson, Bradley N. White (2012). "Conservation genomics in perspective: A holistic approach to understanding Canis evolution in North America". Biological Conservation 155: 186–192. doi:10.1016/j.biocon.2012.05.017. Retrieved 2013-07-01.
- Atkins, D. and L.Dillon. 1971. Evolution of the cerebellum in the genus Canis. J. Mammal. 52:96-97.
- Paradiso, J. 1968. Canids recently collected in east Texas, with comments on the taxonomy of the red wolf. Am. Midl. Nat. 80:529-34.
- Ferrell et al. 1980. Biochemical markers in species endangered by introgression: The red wolf. Biochem. Genet. 18:39-49.
- Lawrence,B. and W. Bossert. 1975. Relationships of North American Canis shown by a multiple character analysis of selected populations. P. 73-86 in M.W. Fox, ed., The wild canids: Their systematic, behavioral ecology, and evolution. Van Nostrand Reinhold, New York.
- Mech, L.1970. The wolf: The ecology and behavior of an endangered species. Natural History Press, Garden City, NY.
- Wayne, R. and S.Jenks. 1991. Mitochondrial DNA analysis supports extensive hybridization of the endangered red wolf (Canis rufus)" Nature 351:565-68.
- Phillips, M. & Henry, V. (1992). Comments on red wolf taxonomy. Conservation Biology, 6:596–599.
- Nowak, R. (1992). The red wolf is not a hybrid. Conservation Biology, 6:593–595.
- Nowak et al. (1995). Another look at wolf taxonomy. pp 375–397 In L.N. Carbyn, S.H. Fritts, and D.R. Seip, eds. Ecology and conservation of wolves in a changing world. Canadian Circumpolar Institute, Edmonton, Alberta.
- Koblmuller, S., Nord, M., Wayne, R. K. and J. Leonard. (2009). Origin and Status of the Great Lakes wolf. Molecular Ecology, 18:2313–2326.
- Nowak, R. M. (2002). The original status of Wolves in Eastern North America. Southeastern Naturalist, 1:95–130
- T. DeLene Beeland (2013). The Secret World of Red Wolves. Chapel Hill, NC: University of North Carolina Press. ISBN 9781469601991.
- "US Fish and Wildlife Species Profile". USFWS. Retrieved 2013-07-08.
- Esch, Mary. "Study: Eastern wolves are hybrids with coyotes". AP News. Retrieved 1 June 2011.
- Paul J. Wilson, Linda Y. Rutledge, Tyler J. Wheeldon, Brent R. Patterson & Bradley N. White (2012). "Y-chromosome evidence supports widespread signatures of three-species Canis hybridization in eastern North America". Ecology and Evolution 2 (9): 2325–2332. doi:10.1002/ece3.301. Retrieved 2013-07-01.
- Astrid V. Stronen, Nathalie Tessier, Hélène Jolicoeur, Paul C. Paquet, Michel Hénault, Mario Villemure, Brent R. Patterson, Tim Sallows, Gloria Goulet and François-Joseph Lapointe (2012). "Canid hybridization: contemporary evolution in human-modified landscapes". Ecology and Evolution 2 (9): 2128–2140. doi:10.1002/ece3.335. Retrieved 2013-07-01.
- E.A. Goldman. (1937). The wolves of North America. Journal of Mammology, 18:37–45.
- "Red Wolf Recovery Program". U.S. Fish and Wildlife Program. Retrieved 2013-07-02.
- W. W. Dalquest and G. E. Schultz 1992. Ice Age mammals of northwestern Texas
- B. Kurten and E. Anderson. 1980. Pleistocene mammals of North America 1-442
- Wilson, P.J., S. Grewal, I.D. Lawford, J.N.M. Heal, A.G. Granacki, D. Pennock, J.B. Theberge, M.T. Theberge, D.R. Voigt, W. Waddell, R.E.Chambers, P.C. Paquet, G. Goulet, D. Cluff, and B.N. White. 2000. DNA profiles of the eastern Canadian wolf and the red wolf provide evidence for a common evolutionary history independent of the gray wolf. Canadian Journal of Zoology 78:2156 - 2166.
- J. Michael Smith: The Highland King Nimhammaw and the Native Indian Proprietors of Land in Dutchess County, NY: 1712-1765. Hudson River Valley Review
- Wolves of Algonquin Provincial Park
- Darwin, Charles (1859), "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life", Nature (Full image view 1st ed.) (London: John Murray) 5 (121): 92, Bibcode:1872Natur...5..318B, doi:10.1038/005318a0, retrieved 2011-03-01
- Powell, W. S. (1973). Creatures of North Carolina from Roanoke Island to Purgatory Mountain. North Carolina Historical Review, 50 (2 ), 121-168.
- U.S. Fish and Wildlife Service.1997. Endangered Red Wolves. http://library.fws.gov/Pubs4/endangered_red_wolves.pdf:p7.
- Nowak, R. M. (2002). The original status of wolves in eastern North America. Southeastern Naturalist, 1(2), 95-130.
- "Current Red Wolf Facts," found on the Red Wolf Recovery web page, http://www.fws.gov/redwolf/index.html, accessed on July 5, 2011.
- Phillips et al.2003. Restoration of the Red Wolf ‘’In’’Wolves, Behavior, Ecology and Conservation. Edited by Mech, D and Boitain, L.,University of Chicago Press, University of Chicago Press.
- Camuto, C. (2000), Another Country: Journeying Toward the Cherokee Mountains, University of Georgia Press, ISBN 0820322377
- Panther-Yates, D. N. (2013), Cherokee Clans: An Informal History, Panther`s Lodge Publishers, p. 7.
- Lopez, B. H. (1978), Of Wolves and Men, J. M. Dent and Sons Limited, p. 109, ISBN 0-7432-4936-4
- Carley,C.1975.Activities and findings of the red wolf recovery program from late 1973 to July 1, 1975. U.S. Fish and Wildlife Service, Albuquerque,NM.
- McCarley,H. and J. Carley. 1979. Recent changes in distribution and status of red wolves (Canis rufus) Endangered Species Report no.4. U.S. Fish and Wildlife Service, Albuquerque, NM.
- Carley, Curtis J. 1979. "Report on the Successful Trans location Experiment of Red Wolves (Canis rufus) to Bulls Island, S.C." Presentation at the Portland Wolf Symposium, Lewis and Clark College, Portland, Oregon, August 13–17, 1979.
- U.S. Fish and Wildlife Service Cape Romain NWR, red wolf web page
- USFWS.2010. Red Wolf Recovery Program, 1st Quarter Report, October–December 2010, Manteco, NC.
- U.S. Fish and Wildlife Service. 2007. Red Wolf (Canis rufus) 5-Year Status Review: Summary and Evaluation.
- Beeland, T. D. (2013). The Secret World of Red Wolves: The Fight to Save America's Other Wolf. 256 pages. Chapel Hill: University of North Carolina Press.
- Chambers, S. M., Fain, S. .R, Fazio, B., & Amaral, M. (2012). An account of the taxonomy of North American wolves from morphological and genetic analyses. North American Fauna, 77, 1–67.
- ^ R. Nowak, R.M. (1992). "The red wolf is not a hybrid.". Conservation Biology 6 : 593-595.
- Nowak, R. M. (1979). North American Quaternary Canis. Unpublished Monograph, University of Kansas Hays.
- Nowak, R. M. (2002). The original status of wolves in eastern North America. Southeastern Naturalist, 1(2), 95-130.
- Nowak, R. M. (2003). Chapter 9: Wolf evolution and taxonomy. In D. Mech & L. Boitani (Eds.), Wolves: Behavior, Ecology, and Conservation (pp. 239–258). Chicago: University of Chicago Press.
- Philips, M. K., Kelly, B., & Henry, G. (2003). Restoration of the red wolf In D. Mech & L. Boitani (Eds.), "Wolves: Behavior, Ecology, and Conservation (pp. 272–288). Chicago: University of Chicago Press.
- ^ Roy, M.S., Geffen, E., Smith, D., Ostrander, E.A. & Wayne, R.K. (1994). "Patterns of differentiation and hybridization in North American wolflike canids, revealed by analysis of micro satellite loci.". Molecular Biology and Evolution 11 : 553–570.
- ^ Roy, M.S., Girman, D.G., Taylor, A.C. & Wayne, R.K. (1994). "The use of museum specimens to reconstruct the genetic variability and relationships of extinct populations.". Experientia 50 : 551-557.
- ^ Silverstein, A., Silverstein, V. B. & Silverstein, R. A. (1994). "The Red wolf: endangered in America.". Brookfield: Conn. Millbrook Press.
- ^ Wayne, R.K. & Jenks, S.M. (1991). "Mitochondrial DNA analysis implying extensive hybridization of the endangered red wolf Canis rufus". Nature 351 : 565-568.
- ^ Wayne, R.K., Lehman, N., Allard, M.W. & Honeycutt, R.L. (1992). "Mitochondrial DNA variability of the grey wolf - genetic consequences of population decline and habitat fragmentation". Conservation Biology 6 : 559-569.
- Wilson, P. J., Grewal, S., Lawford, I. D., Heal, J. N. M., Granacki, A. G., Pennock, D., et al. (2000). DNA profiles of the eastern Canadian wolf and the red wolf provide evidence for a common evolutionary history independent of the gray wolf Canadian Journal of Zoology, 78, 2156–2166.
|Wikispecies has information related to: Canis rufus|
|Wikimedia Commons has media related to Canis rufus.|