Red wolf

Taxonomy

The taxonomic reference Mammal Species of the World (2005) does not recognize Canis rufus; however, NCBI/Genbank does list it.

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% coyote and only 20–24% gray wolf, suggesting that the red wolf is actually much more coyote in origin than the eastern wolf. This study analyzed 48,000 single nucleotide polymorphisms (SNPs) 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, whether loci important to red wolf genetic variation were actually identified and analyzed (for example, nuclear DNA was not compared in the SNP analysis) remains unclear. 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.

In 2013, an experiment which produced hybrids of coyotes and northwestern gray wolves in captivity using artificial insemination contributed more information to the controversy surrounding the eastern wolf's taxonomy. The purpose of this project was to determine whether the female western coyotes are capable of bearing hybrid western gray wolf-coyote pups, as well as to test the hybrid theory surrounding the origin of the eastern and red wolves by comparing them to both. The resulting six hybrids produced in this captive artificial breeding were later transferred to the Wildlife Science Center of Forest Lake in Minnesota, where their behaviors are now being studied. However, by 1999, introgression of coyote genes was recognized as the single greatest threat to wild red wolf recovery and an adaptive management plan which included coyote sterilization has been successful, with coyote genes being reduced by 2015 to < 4% of the wild red wolf population. A 2016 genetic study of canid scats found that despite high coyote density inside the Red Wolf Experimental Population Area (RWEPA), hybridization occurs rarely (4% are hybrids) as a result of the management plan and red wolf mate choice/assortative mating. High wolf mortality related to anthropogenic causes appeared to be the main factor limiting wolf dispersal westward from the RWEPA. High anthropogenic wolf mortality similarly limits expansion of eastern wolves outside of protected areas in south-eastern Canada.

In 2014, the review of Chambers et al. (2012) which suggested the eastern wolf should be listed either as a distinct species closely related to the red wolves or conspecific with the latter became controversial, forcing the USFWS to commission a peer review of it, known as NCAES (2014), which took issue with the review. However, more recent reviews suggest the evidence has "tilted towards a North American canid assemblage composed of the eastern wolf, red wolf and coyote as distinct taxa...that descended from a common ancestral canid of North American origin" before arrival of the gray wolf from Eurasia.

Whole-genome analysis

In early 2016, an mDNA analysis of 3 ancient (300–1900 years old) wolf-like samples from the south-eastern United States found that they grouped with the coyote clade, although their teeth were wolf-like. The study proposed that the specimens were either coyotes and this would mean that coyotes had occupied this region continuously rather than intermittently, a North American evolved red wolf lineage related to coyotes, or an ancient coyote–wolf hybrid. Ancient hybridization between wolves and coyotes would likely have been due to natural events or early human activities, not landscape changes associated with European colonization because of the age of these samples. Coyote–wolf hybrids may have occupied the southeastern United States for a long time, filling an important niche as a large predator.

In July 2016, a whole-genome DNA study proposed, based on the assumptions made, that all of the North American wolves and coyotes diverged from a common ancestor less than 6,000–117,000 years ago. The study also indicated that all North America wolves have a significant amount of coyote ancestry and all coyotes some degree of wolf ancestry, and that the red wolf and Great Lakes region wolf are highly admixed with different proportions of gray wolf and coyote ancestry. One test indicated a wolf/coyote divergence time of 51,000 years before present that matched other studies indicating that the extant wolf came into being around this time. Another test indicated that the red wolf diverged from the coyote between 55,000–117,000 years before present and the Great Lakes region wolf 32,000 years before present. Other tests and modelling showed various divergence ranges and the conclusion was a range of less than 6,000 and 117,000 years before present. The study found that coyote ancestry was highest in red wolves from the southeast of the United States and lowest among the Great Lakes region wolves. The theory proposed was that this pattern matched the south to north disappearance of the wolf due to European colonization and its resulting loss of habitat. Bounties led to the extirpation of wolves initially in the south east, and as the wolf population declined wolf-coyote admixture increased. Later, this process occurred in the Great Lakes region with the influx of coyotes replacing wolves, followed by the expansion of coyotes and their hybrids across the wider region. The red wolf may possess some genomic elements that were unique to gray wolf and coyote lineages from the American South. The proposed timing of the wolf/coyote divergence conflicts with the finding of a coyote-like specimen in strata dated to 1 million years before present, and red wolf fossil specimens dating back 10,000 years ago.

The study concluded by stating that because of the extirpation of gray wolves in the American Southeast, "the reintroduced population of red wolves in eastern North Carolina is doomed to genetic swamping by coyotes without the extensive management of hybrids as is currently practiced by the USFWS."

In September 2016, the USFWS announced a program of changes to the red wolf recovery program and "will begin implementing a series of actions based on the best and latest scientific information". The service will secure the captive population which is regarded as not sustainable, determine new sites for additional experimental wild populations, revise the application of the existing experimental population rule in North Carolina, and complete a comprehensive Species Status Assessment.

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. A study of Canis morphometrics conducted in eastern North Carolina reported that red wolves are morphometrically distinct from coyotes and hybrids. Adults measure 136–160 cm (53.5–63 in) in length, and weigh 23–39 kg (50-85 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 plesiomorphic 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.

Using long-term data on red wolf individuals of known pedigree, it was found that inbreeding among first-degree relatives was rare. A likely mechanism for avoidance of inbreeding is independent dispersal trajectories from the natal pack. Many of the young wolves spend time alone or in small non-breeding packs composed of unrelated individuals. The union of two unrelated individuals in a new home range is the predominant pattern of breeding pair formation. Inbreeding is avoided because it results in progeny with reduced fitness (inbreeding depression) that is predominantly caused by the homozygous expression of recessive deleterious alleles.

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 southeastern United States from the Atlantic and Gulf Coasts, north to the Ohio River Valley and central Pennsylvania, and west to Central Texas and southeastern Missouri. 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. In 1998, the FWS removed the remaining red wolves in the Great Smoky Mountains National Park, relocating them to Alligator River National Wildlife Refuge in eastern North Carolina. 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 used a large suite of habitat types at one time. The last naturally occurring population used coastal prairie marshes, swamps, and agricultural fields used to grow rice and cotton. However, this environment probably does not typify preferred red wolf habitat. Some evidence shows the species was found in highest numbers in the once extensive bottom-land river forests and swamps of the southeastern United States. Red wolves reintroduced into northeastern North Carolina have used habitat types ranging from agricultural lands to forest/wetland mosaics characterized by an overstory 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 extirpation in the wild

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. Cherokees generally avoided killing red wolves, as such an act was believed to 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 USFWS. 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 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 December 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 translocation lasted for 11 days, during which a mated pair of red wolves was monitored day and night with remote telemetry. A second experimental translocation 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 ARNWR 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.

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 USFWS estimated that 300 red wolves remained in the world, with 207 of those in captivity.

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.

Over 30 facilities participate in the red wolf Species Survival Plan and oversee the breeding and reintroduction of over 150 wolves.

In 2012, the Southern Environmental Law Center filed a lawsuit against the North Carolina Wildlife Resources Commission for jeopardizing the existence of the wild red wolf population by allowing nighttime hunting of coyotes in the five-county restoration area in eastern North Carolina. A 2014 court-approved settlement agreement was reached that banned nighttime hunting of coyotes and requires permitting and reporting coyote hunting. In response to the settlement, the North Carolina Wildlife Resources Commission adopted a resolution requesting the USFWS to remove all wild red wolves from private lands, terminate recovery efforts, and declare red wolves extinct in the wild. This resolution came in the wake of a 2014 programmatic review of the red wolf conservation program conducted by The Wildlife Management Institute. The Wildlife Management Institute indicated the reintroduction of the red wolf was an incredible achievement. The report indicated that red wolves could be released and survive in the wild, but that illegal killing of red wolves threatens the long-term persistence of the population. The report stated that the USFWS needed to update its red wolf recovery plan, thoroughly evaluate its strategy for preventing coyote hybridization and increase its public outreach. Since the programmatic review, the USFWS ceased implementing the red wolf adaptive management plan that was responsible for preventing red wolf hybridization with coyotes and allowed the release of captive-born red wolves into the wild population. Since then, the wild population has decreased from 100–115 red wolves to 50–65.

In 2014, the USFWS issued the first take permit for a red wolf to a private landowner. Since then, the USFWS issued several other take permits to landowners in the five-county restoration area. During June 2015, a landowner shot and killed a female red wolf after being authorized a take permit, causing a public outcry. In response, the Southern Environmental Law Center filed a lawsuit against the USFWS for violating the Endangered Species Act.