Red wolf: Difference between revisions

{{Short description|Canid native to the southeastern United States}}

{{About|the wild canine}}

{{Speciesbox

| status = CR

| status_system = IUCN3.1

By fall of 2021, a total of six red wolves had been killed, including the four adults that had been released in the spring. Three of the released adults had been killed in vehicle collisions, two had died from unknown cases, and the fourth released adult had been shot by a landowner who feared the wolf was attempting to get his chickens. These losses dropped the number of wolves in the wild down to about 20 wild individuals. In the winter of 2021–2022, the Fish and Wildlife Services selected nine captive adult red wolves to be released into the wild. A family of five red wolves were released into the Pocosin Lakes National Wildlife Refuge, while two new breeding pairs of adult wolves were released into the Alligator River National Wildlife Refuge. The release of these new wolves brought the number of wild red wolves in eastern North Carolina up to less than 30 wild individuals.{{citation needed|date=March 2022}}

 

 

===Current population===

In 2021, the [[American Society of Mammalogists]] considered the red wolf as its own species (''Canis rufus'').<ref>{{cite web |title=''Canis rufus'' Audubon & Bachman, 1851 |work=ASM Mammal Diversity Database: Explore the Database |url=https://www.mammaldiversity.org/explore.html#genus=Canis&species=rufus&id=1005945 |access-date=2023-05-25}}</ref><ref name=vonholdt2016/>

 

When European settlers first arrived to North America, the coyote's range was limited to the western half of the continent. They existed in the arid areas and across the open plains, including the prairie regions of the midwestern states. Early explorers found some in Indiana and Wisconsin. From the mid-1800s onward, coyotes began expanding beyond their original range.<ref name=nowak1979/>

 

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The [[paleontologist]] Ronald M. Nowak notes that the oldest fossil remains of the red wolf are 10,000&nbsp;years old and were found in Florida near [[Melbourne, Florida|Melbourne]], [[Brevard County, Florida|Brevard County]], Withlacoochee River, [[Citrus County, Florida|Citrus County]], and [[Devil's Den Cave]], [[Levy County, Florida|Levy County]]. He notes that there are only a few, but questionable, fossil remains of the gray wolf found in the southeastern states. He proposes that following the extinction of the [[dire wolf]], the coyote appears to have been displaced from the southeastern US by the red wolf until the last century, when the extirpation of wolves allowed the coyote to expand its range. He also proposes that the ancestor of all North American and Eurasian wolves was ''[[Canis variabilis#Canis mosbachensis|C.&nbsp;mosbachensis]]'', which lived in the [[Middle Pleistocene]] 700,000–300,000&nbsp;years ago.<ref name=nowak2002/>

 

The [[paleontologist]] and expert on the genus ''Canis''{{'}} natural history, [[Xiaoming Wang (paleontologist)|Xiaoming Wang]], looked at red wolf fossil material but could not state if it was, or was not, a separate species. He said that Nowak had put together more [[morphometric]] data on red wolves than anybody else, but Nowak's statistical analysis of the data revealed a red wolf that is difficult to deal with. Wang proposes that studies of [[ancient DNA]] taken from fossils might help settle the debate.<ref name=beeland2013/>

 

[[File:John Woodhouse Audubon - Red Texas Wolf (Canis Lupus) - Google Art Project.jpg|thumb|Audubon's depiction of the red wolf (1851)]]

[[File:The Wolves of North America (1944) C. lupus, rufus & latrans.jpg|thumb|Skulls of North American canines, with the red wolf in the center]]

In the late 19th century, sheep farmers in [[Kerr County, Texas]], stated that the coyotes in the region were larger than normal coyotes, and they believed that they were a gray wolf and coyote cross.<ref name=nowak1979/> In 1970, the wolf mammalogist [[L. David Mech]] proposed that the red wolf was a hybrid of the gray wolf and coyote.<ref name=mech1970/> However, a 1971 study compared the [[cerebellum]] within the brain of six ''Canis'' species and found that the cerebellum of the red wolf indicated a distinct species, was closest to that of the gray wolf, but in contrast indicated some characteristics that were more primitive than those found in any of the other ''Canis'' species.<ref name=atkins1971/> In 2014, a three-dimensional [[Morphometrics#Landmark-based geometric morphometrics|morphometrics]] study of ''Canis'' species accepted only six red wolf specimens for analysis from those on offer, due to the impact of hybridization on the others.<ref name=schmitt2014/>

 

Different DNA studies may give conflicting results because of the specimens selected, the technology used, and the assumptions made by the researchers.<ref name=boyko2009/>{{efn| Any one from a panel of [[genetic marker]]s can be chosen for use in a study. The techniques used to [[DNA extraction|extract]], [[DNA sequencing|locate]] and [[DNA analysis|compare]] genetic sequences can be applied using advances in technology, which allows researchers to observe longer lengths of [[Base pair#Length measurements|base pairs]] that provide more data to give better [[phylogenetic]] resolution.<ref name=pang2009/>}}

 

[[Phylogenetic trees]] compiled using different [[genetic markers]] have given conflicting results on the relationship between the wolf, dog and coyote. One study based on [[Single-nucleotide polymorphism|SNPs]]<ref name=cronin2014/> (a single [[mutation]]), and another based on [[nuclear gene]] sequences<ref name=bardeleben2005/> (taken from the [[cell nucleus]]), showed dogs clustering with coyotes and separate from wolves. Another study based on SNPS showed wolves clustering with coyotes and separate from dogs.<ref name=gray2010/> Other studies based on a number of markers show the more widely accepted result of wolves clustering with dogs separate from coyotes.<ref name=vila1997/><ref name=wayne2012/> These results demonstrate that caution is needed when interpreting the results provided by genetic markers.<ref name=cronin2014/>

 

In 1980, a study used [[gel electrophoresis]] to look at fragments of DNA taken from dogs, coyotes, and wolves from the red wolf's core range. The study found that a unique [[allele]] (expression of a [[gene]]) associated with [[Lactate dehydrogenase]] could be found in red wolves, but not dogs and coyotes. The study suggests that this allele survives in the red wolf. The study did not compare gray wolves for the existence of this allele.<ref name=ferrell1980/>

 

Brzeski ''et al''. (2016)<ref name=brzeski2016/> conducted an mDNA analysis of three ancient (300–1,900&nbsp;years old) wolf-like samples from the southeastern 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.<ref name=brzeski2016/> Coyote–wolf hybrids may have occupied the southeastern United States for a long time, filling an important niche as a medium-large predator.<ref name=roy1996/><ref name=brzeski2016/>

 

[[File:Red Wolf (1980).png|right|thumb|A red wolf in the forest]]

In July 2016, a [[Whole genome sequencing|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 [[Genetic admixture|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 and 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.

In 2019, a [[literature review]] of the previous studies was undertaken by the [[National Academies of Sciences, Engineering, and Medicine]]. The position of the National Academies is that the historical red wolf forms a valid taxonomic species, the modern red wolf is distinct from wolves and coyotes, and modern red wolves trace some of their ancestry to historic red wolves. The species ''Canis rufus'' is supported for the modern red wolf, unless genomic evidence from historical red wolf specimens changes this assessment, due to a lack of continuity between the historic and the modern red wolves.<ref>{{cite book |doi=10.17226/25351 |pmid=31211533 |title=Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf |year=2019 |isbn=978-0-309-48824-2 |department=Board on Life Sciences |publisher=National Academies of Sciences and Engineering|last1=National Academies Of Sciences |first1=Engineering |s2cid=134662152 }}</ref>

 

Genetic studies relating to wolves or dogs have inferred phylogenetic relationships based on the only reference genome available, that of the [[Boxer (dog)|Boxer dog]]. In 2017, the first reference genome of the wolf ''Canis lupus lupus'' was mapped to aid future research.<ref name=gopalakrishnan2017/> In 2018, a study looked at the genomic structure and admixture of North American wolves, wolf-like canids, and coyotes using specimens from across their entire range that mapped the largest dataset of nuclear genome sequences against the wolf reference genome. The study supports the findings of previous studies that North American gray wolves and wolf-like canids were the result of complex gray wolf and coyote mixing. A [[Greenland wolf|polar wolf from Greenland]] and a coyote from Mexico represented the purest specimens. The coyotes from Alaska, California, Alabama, and Quebec show almost no wolf ancestry. Coyotes from Missouri, Illinois, and Florida exhibit 5–10% wolf ancestry. There was 40%:60% wolf to coyote ancestry in red wolves, 60%:40% in Eastern timber wolves, and 75%:25% in the Great Lakes wolves. There was 10% coyote ancestry in Mexican wolves and Atlantic Coast wolves, 5% in Pacific Coast and [[History of wolves in Yellowstone|Yellowstone wolves]], and less than 3% in Canadian archipelago wolves.<ref name=sinding2018/>

 

The Endangered Species Act provides protection to endangered species, but does not provide protection for endangered admixed individuals, even if these serve as reservoirs for extinct genetic variation. Researchers on both sides of the red wolf debate argue that admixed canids warrant full protection under this Act.<ref name=heppenheimer2018/><ref name=vonholdt2016/>

 

In 2020, a study conducted DNA sequencing of [[Canis|canines]] across southeastern US to detect those with any red wolf ancestry. The study found that red wolf ancestry exists in the coyote populations of southwestern Louisiana and southeastern Texas, but also newly detected in North Carolina. The red wolf ancestry of these populations possess unique red wolf alleles not found in the current captive red wolf population. The study proposes that the expanding coyotes admixed with red wolves to gain genetic material that was suited to the southeastern environment and would aid their adaptation to it, and that surviving red wolves admixed with coyotes because the red wolves were suffering from inbreeding.<ref name=Heppenheimer2020/>

 

In 2021, a study conducted DNA sequencing of canines across the remnant red wolf hybrid zone of southwestern Louisiana and southeastern Texas. The study found red wolf ancestry in the coyote genomes which increases up to 60% in a westward gradient. This was due to introgression from the remnant red wolf population over the past 100 years. The study proposes that coyotes expanded into the [[Gulf of Mexico|gulf]] region and admixed with red wolves prior to the red wolf going extinct in the wild due to loss of habitat and persecution. In the past two decades the hybrid region has expanded. The study presented the genetic evidence that the red wolf is a separate species, based on the structure of one of the [[Locus (genetics)|loci]] of its [[X-chromosome]] which is accepted as a marker for distinct species. As such, the study suggested that the introgressed red wolf ancestry could be de-introgressed back as a basis for breeding further red wolves from the hybrids.<ref name=Vonholdt2021/>

 

In 2021, a study of mitochondrial genomes sourced from specimens dated before the 20th century revealed that red wolves could be found across North America. With the arrival of the gray wolf between 80,000 and 60,000 years ago, the red wolf's range shrank to the eastern forests and California, and the coyote replaced the red wolf mid-continent between 60,000 and 30,000 years ago. The coyote expanded into California at the beginning of the [[Holocene]] era 12,000–10,000 years ago and admixed with the red wolf, phenotypically replacing them. The study proposes that the red wolf may pre-date the coyote in North America.<ref name=Sacks2021/>

 

<ref name=bailey1905>{{cite journal |author=Bailey, V. |year=1905 |title=Biological survey of Texas: Life zones, with characteristic species of mammals, birds, reptiles, and plants |quote=Reptiles, with notes of distribution. Mammals, with notes on distribution, habits and economic importance. |journal=North American Fauna |volume=25 |page=174 |doi=10.3996/nafa.25.0001 |doi-access=free |url=https://www.biodiversitylibrary.org/item/164094#page/208/mode/1up}}</ref>

 

 

<ref name=bartram1791>{{cite book |author=Bartram, W. |orig-year=1791 |year=1794 |title=Travels through North and South Carolina, Georgia, East and West Florida, the Cherokee Country, the Extensive Territories of the Muscogulges or Creek Confederacy, and the Country of the Chactaws |quote=Containing an Account of the Soil and Natural Productions of Those Regions; Together with Observations on the Manners of the Indians. |publisher=James & Johnson |place=Philadelphia, PA / London, UK |page=197 |edition=2nd |url=https://archive.org/stream/travelsthroughno00bart#page/196/mode/2up/search/wolf}}</ref>

<ref name=nowak1995a>{{cite conference |author1=Nowak, R.M. |author2=Phillips, M.K. |author3=Henry, V.G. |author4=Hunter, W.C. |author5=Smith, R. |year=1995 |article=The origin and fate of the red wolf |title=Ecology and Conservation of Wolves in a Changing World |conference=Second North American Symposium on Wolves |pages=409–415 |editor1=Carbyn, L.N. |editor2=Fritts, S.H. |editor3=Seip, D.R. |department=Canadian Circumpolar Institute |publisher=University of Alberta |place=Edmonton, AB}}</ref>

 

 

<ref name=nowak2002>{{cite journal |doi=10.1656/1528-7092(2002)001[0095:TOSOWI]2.0.CO;2 |year=2002 |volume=1 |issue=2 |pages=95–130 |title=The Original Status of Wolves in Eastern North America |journal=Southeastern Naturalist |last1=Nowak |first1=Ronald M. |s2cid=43938625 }}</ref>

<ref name=wayne1991>{{cite journal |doi=10.1038/351565a0 |title=Mitochondrial DNA analysis implying extensive hybridization of the endangered red wolf ''Canis rufus'' |journal=Nature |volume=351 |issue=6327 |page=565 |year=1991 |last1=Wayne |first1=R.K. |last2=Jenks |first2=S.M. |bibcode=1991Natur.351..565W |s2cid=4364642}}</ref>

 

 

<ref name=wayne2012>{{cite journal |doi=10.1007/s00335-011-9386-7 |pmid=22270221 |title=Evolutionary genomics of dog domestication |journal=Mammalian Genome |volume=23 |issue=1–2 |pages=3–18 |year=2012 |last1=Wayne |first1=Robert K. |last2=vonHoldt |first2=Bridgett M. |s2cid=16003335}}</ref>

{{Grey wolf subspecies}}

 

 

[[Category:Mammals described in 1851]]