Falklands 'wolf' that baffled Darwin was actually more like a jackal – new study Falklands 'wolf' that baffled Darwin was actually more like a jackal – new study BY EARTH TOUCH NEWS JANUARY 11 2017        

Carlo Meloro, Liverpool John Moores University

When Charles Darwin stopped briefly at the Falkland Islands on the famous voyage of the Beagle, he ran into one of the great mysteries in animal evolution. The islands had just one native terrestrial mammal, which he confusingly described as a “wolf-like fox”. It wasn’t clear what the species was descended from, or how it had ended up in such a remote place, hundreds of kilometres from the nearest mainland.

The Falkland Islands wolf, known also as the warrah or Dusicyon australis, was hunted to extinction in the latter half of the 19th century. As such it was little studied. Darwin’s visit, in the species’ final decades, remains one of the only scientific observations of this poor animal.

Scientists long thought that the extinct Falklands wolf was, as its name suggests, similar to a wolf. However, new research by colleagues and me published in the journal Mammal Review reveals that, in terms of skull shape and feeding habits, this mysterious “wolf” was more like a jackal.

Where it came from

The Falklands wolf had previously been linked to wolves, coyotes and domestic dogs, and scientists even named it Canis antarticus. It wasn’t until 2009 that DNA analysis was used to prove its closest living relative is the maned wolf of South America, which is actually neither a wolf nor a fox. Nevertheless, this species of wild canid (the wider dog family) is characterised by unusually tall limbs, which make it very different from the rather sturdy Falklands wolf.

The "Antarctic wolf", 1890. JG Keulemans / BHL, CC BY-NC-SA

So where did the Falklands wolf come from? By looking through the South American fossil record, scientists identified its direct ancestor as an extinct fox known as Dusicyon avus which was once found as far south as Patagonia. A 2013 study found Falklands wolf DNA split from its mainland ancestors about 16,000 years ago – during the last ice age.

At that point, when sea levels were much lower, Patagonia was only separated from the Falklands by a small passage of shallow sea which would have frozen over at times. This meant Dusicyon avus probably walked across an ice bridge to the Falklands, before evolving in complete isolation into the warrah.

From wolf to jackal

Mystery solved. So we now know where the warrah came from, but what was it actually like? I wanted to figure out its ecology, and that meant looking at its bones and comparing them to other canids and what we know about their behaviour.

To do this, I worked with a team of LJMU colleagues, a paleontologist from Argentina, and curators at the Natural History Museum (NHM) in London. We dug through the cupboards at the NHM and World Museum Liverpool to build a database of more than 120 digital images of representative skulls of living wild canid species, including rare specimens of Falklands wolf and its ancestor Dusicyon avus.

We then mapped out various anatomical landmarks that would be present in each (the tip of the upper and lower jaw, say, or the relative position of upper and lower canines and molar teeth) and used this information to quantify the shape of all the wild canid skulls we investigated. This gave us directly comparable data which helps reveal similarities and differences between species.

Geometric morphology: anatomical landmarks (on the left) are turned into easily-comparable digital images. Meloro et al, Author provided

We realised the Falklands wolf and Dusicyon avus most closely resembled the jackal species found in Africa and Eurasia. Shared features such as wide elongated muzzles, narrow cheekbones, large first lower molars and thick lower jaws, are typical of medium-sized opportunistic predators.

As with jackals alive today, the Falklands wolf would have been an unfussy eater, capable of scavenging or killing everything from small ground-nesting birds to marine mammals like seal pups. Jackal-like feeding habits may even have determined the fate of these "wolves", as they would also have targeted sheep which were imported to the Falklands from the 1850s onwards.

As with jackals alive today, the Falklands wolf would have been an unfussy eater. Image: Pim Stouten, Flickr

The Falkland Islands wolf is one of many species that, after colonising South America, quickly evolved features similar to distantly-related counterparts in the Old World. The bush dog of South America is another. With its short muzzle and wide cheekbones, this small canid resembles in skull morphology the much larger African hunting dog and the Asiatic dhole. All three species hunt in packs and independently converged on the same head shape, which gives them an unusually strong bite and means they can grab hold of fleeing large prey like deer or capybara.

South America represented an important “laboratory” for the natural selection of modern canid species. The continent now has the world’s richest diversity of dogs, wolves and their relatives. The historical loss of the Falkland Islands wolf highlights, again, that humans are their greatest threat.

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Top header image: Charles Darwin's Zoology of the Voyage of the Beagle, 1838 / The Trustees of the Natural History Museum, London, CC BY-NC-SA

Carlo Meloro, Lecturer in Vertebrate Palaeoecology, Liverpool John Moores University

This article was originally published on The Conversation. Read the original article.

Dusicyon australisFalkland Island wolf  

Ge­o­graphic Range

Falk­land Is­lands wolves, Du­si­cyon aus­tralis, also known as war­rah, are found only on the Falk­land Is­lands, an arch­i­pel­ago off the coast of south­ern South Amer­ica. Their clos­est liv­ing rel­a­tive, Chryso­cyon brachyu­rus, is found on the main­land of South Amer­ica. (Dar­win, 1839; IUCN SSC Canid Spe­cial­ist Group 2008, 2008; Slater, et al., 2009a)

• Biogeographic Regions
• neotropical 
   
  • native 

• Other Geographic Terms
• island endemic

Habi­tat

Falk­land Is­lands wolves lived on both the east and west sides of the is­lands. They in­habit rocky moun­tain­ous ter­rain or boggy plains and beaches. They were re­port­edly seen swim­ming while for­ag­ing along the beaches. These wolves ap­par­ently oc­cu­pied bur­rows in the sand-hills. A find­ing in 2010 seems to con­firm this: teeth and skulls of D. aus­tralis were found in a col­lapsed bur­row in the Falk­land Is­lands. Re­searchers spec­u­late that D. aus­tralis did not dig the bur­rows but rather lived in bur­rows made by pen­guins or other an­i­mals. (CIA, 2012; Dar­win, 1839; Falk­land Is­lands Mu­seum and Na­tional Trust, 2012; Hamil­ton Smith, 1843; Ren­shaw, 1905)

• Habitat Regions
• temperate 
• terrestrial

• Terrestrial Biomes
• savanna or grassland

• Aquatic Biomes
• coastal

• Wetlands
• bog

• Range elevation

  705 (high) m

  2312.99 (high) ft

Phys­i­cal De­scrip­tion

Falk­land Is­lands wolves were medium-sized, bulky, and fox-like. The legs were short, as was their tails. When they were stand­ing, the tail typ­i­cally did not reach the ground. The coat was thick, with mix­tures of tawny, tan, and black hairs dor­sally; the coat be­came paler ven­trally. The neck and inner legs were white. They had rel­a­tively small pin­nae. The bushy tail was brown in the mid­dle and had a dis­tinc­tively white tip. Falk­land Is­lands wolves had a mix­ture of fox and wolf traits that caused them to re­sem­ble no other liv­ing canid: ac­cord­ing to Dar­win, "all main­tain that no such an­i­mal is found in any part of South Amer­ica" (Dar­win, 1839). ("Falk­land Is­land Wolf Photo", 2012; Dar­win, 1839; Hamil­ton Smith, 1839)

The den­ti­tion in­cluded very large car­nas­sials, no­table since their clos­est liv­ing rel­a­tive, Chryso­cyon brachyu­rus, has greatly re­duced car­nas­sials. The car­nas­sials had a pro­to­cone that pointed nearly back­wards (Os­good, 1934). The skull con­tained a high arch­ing, ex­panded frontal bone and no in­ter­pari­etal crest (Clut­ton-Brock, 1977). ("Falk­land Is­land Wolf Photo", 2012; Os­good, 1934; "Falk­land Is­land Wolf Photo", 2012; Os­good, 1934)

Falk­land Is­lands wolves were the size of large foxes, with an av­er­age head-body length of 97 cm. Height at the shoul­der was 38.1 cm. The tail was be­tween 28.5 and 33 cm long. Mass is un­known. ("Falk­land Is­land Wolf Photo", 2012; Hamil­ton Smith, 1839)

• Other Physical Features
• endothermic 
• homoiothermic 
• bilateral symmetry

• Average length

  97 cm

  38.19 in

Re­pro­duc­tion

There is no in­for­ma­tion avail­able about the mat­ing sys­tems of Falk­land Is­lands wolves. It is pos­si­ble that its mat­ing sys­tem was sim­i­lar to that of its clos­est rel­a­tive, Chryso­cyon brachyu­rus, which is monog­a­mous. The two species, how­ever, dif­fer greatly in ap­pear­ance and be­hav­ior, as they di­verged 6.7 mil­lion years ago, and mat­ing sys­tems may not be alike at all (Slater et al, 2009). ("Falk­land Is­land Wolf Photo", 2012; Slater, et al., 2009b; Slater, et al., 2009a)

There is no in­for­ma­tion avail­able about re­pro­duc­tion of Falk­land Is­lands wolves. (Slater, et al., 2009b; Slater, et al., 2009a)

• Key Reproductive Features
• iteroparous 
• gonochoric/gonochoristic/dioecious (sexes separate) 
• sexual 
• viviparous

Lit­tle is known of the parental in­vest­ment of D. aus­tralis. One con­tem­po­rary ac­count re­lates the cap­ture of three wolves from a bur­row: two cubs with an older male (Falk­land Is­lands Mu­seum and Na­tional Trust, 2012). Ad­di­tion­ally, in 2010 a bur­row with four Falk­land Is­lands wolf skulls, in­clud­ing a ju­ve­nile, was dis­cov­ered. These ob­ser­va­tions and find­ings sug­gest that D. aus­tralis might have had parental habits sim­i­lar to those of other canids who raise young in bur­rows, such as Vulpes vulpes and Ly­caon pic­tus (Ren­shaw, 1905). (Falk­land Is­lands Mu­seum and Na­tional Trust, 2012; Ren­shaw, 1905)

• Parental Investment
• altricial 
• female parental care 
• pre-fertilization 
   
  • provisioning 
  • protecting 
    • female 
   
• pre-hatching/birth 
   
  • provisioning 
    • female 
  • protecting 
    • female 
   
• pre-weaning/fledging 
   
  • provisioning 
    • female 

Lifes­pan/Longevity

There is no in­for­ma­tion avail­able on the lifes­pan of Falk­land Is­lands wolves. (Slater, et al., 2009b; Slater, et al., 2009a)

Be­hav­ior

Some in­ter­ac­tions be­tween Falk­land Is­lands wolves and hu­mans were doc­u­mented. Dar­win noted their par­tic­u­larly gen­tle na­ture, they did not seem to fear hu­mans. The only mam­mal na­tive to the Falk­land Is­lands, these wolves showed traits of "tame­ness and cu­rios­ity" (Dar­win) to­ward human vis­i­tors to the is­lands. Some wolves were re­port­edly do­mes­ti­cated by in­hab­i­tants of the is­lands in the 1800s (Clut­ton-Brock, 1977). Un­for­tu­nately, this un­usual tame­ness was used to their dis­ad­van­tage: as Dar­win notes, men "fre­quently killed them in the evening, by hold­ing out a piece of meat in one hand, and in the other a knife ready to stick them." (Clut­ton-Brock, 1977; Clut­ton-Brock, 1977; Dar­win, 1839)

Lit­tle else is known about Falk­land Is­lands wolf be­hav­ior. This species is ex­tinct; the only ob­ser­va­tions of liv­ing in­di­vid­u­als come from 19th cen­tury pri­mary ac­counts, of which there are few. Nine­teenth cen­tury nat­u­ral­ist Hamil­ton Smith re­ported that D. aus­tralis had a "fee­ble bark" and was ac­tive dur­ing the day. They hunted alone, not in packs (Ren­shaw, 1905). The bur­rows in which the wolves likely slept and raised young were some­times in­ter­con­nected (Ren­shaw, 1905), im­ply­ing in­traspe­cific so­cial in­ter­ac­tions. Hamil­ton Smith noted that the wolves were "so­cial" de­spite their hunt­ing habits. (Falk­land Is­lands Mu­seum and Na­tional Trust, 2012; Hamil­ton Smith, 1839; Hamil­ton Smith, 1843; Ren­shaw, 1905)

• Key Behaviors
• terricolous 
• diurnal 
• motile 
• sedentary 
• social

Home Range

There is no in­for­ma­tion about home range be­hav­ior, al­though it was con­fined to ei­ther the west­ern or east­ern half of the Falk­land Is­lands.

Com­mu­ni­ca­tion and Per­cep­tion

Hamil­ton Smith re­ported that Du­si­cyon aus­tralis tended not to vo­cal­ize often but some­times its cries could be heard at night. In ad­di­tion, after set­tlers col­o­nized the is­lands, the wolves began to "learn a kind of bark­ing." Lit­tle is known about their in­traspe­cific so­cial habits. (Clut­ton-Brock, 1977)

• Communication Channels
• acoustic

• Perception Channels
• visual 
• tactile 
• acoustic 
• chemical

Food Habits

As there were no other mam­mals pre­sent on the Falk­land Is­lands, Du­si­cyon aus­tralis preyed upon birds (es­pe­cially geese and pen­guins), small in­ver­te­brates, and pin­nipeds that they would catch on the shores. In ad­di­tion, Hamil­ton Smith re­ported that these wolves would eat "fish, crabs, limpets, lizards, toads, ser­pents, and in­sects." ("Falk­land Is­land Wolf Photo", 2012; Clut­ton-Brock, 1977; Dar­win, 1839; Slater, et al., 2009a)

• Primary Diet
• carnivore 
   
  • eats terrestrial vertebrates 
  • eats non-insect arthropods 

• Animal Foods
• birds 
• mammals 
• amphibians 
• reptiles 
• insects 
• mollusks 
• aquatic crustaceans

Pre­da­tion

Du­si­cyon aus­tralis was the top preda­tor in its habi­tat and faced no nat­ural pre­da­tion until the col­o­niza­tion of the Falk­land Is­lands by hu­mans.

Ecosys­tem Roles

Du­si­cyon austalis was the dom­i­nant preda­tor in the Falk­land Is­lands.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Ac­cord­ing to Hamil­ton Smith, the set­tlers of the is­lands re­port­edly do­mes­ti­cated some Falk­land Is­lands wolves, al­though to what ex­tent the an­i­mals were tamed is un­known. In ad­di­tion, hunters killed these wolves for their fur, which was sold in the fur trade. The fur in par­tic­u­lar ended up in New York at “the fur stores of Mr G Astor" (Hamil­ton Smith, 1839), who amassed a large num­ber of Falk­land Is­land wolf pelts. (Clut­ton-Brock, 1977; Falk­land Is­lands Mu­seum and Na­tional Trust, 2012; Hamil­ton Smith, 1839; Hamil­ton Smith, 1843; Ren­shaw, 1905)

• Positive Impacts
• body parts are source of valuable material

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Al­though Du­si­cyon aus­tralis did not often rep­re­sent a threat to­ward hu­mans be­cause of its rel­a­tive tame­ness, there were scat­tered re­ports of wolf at­tacks on hu­mans. These wolves may have rep­re­sented a threat to live­stock, al­though nat­u­ral­ist Gra­ham Ren­shaw ar­gued that this fear was un­sub­stan­ti­ated (Ren­shaw, 1905). Nonethe­less, the wolf was hunted to ex­tinc­tion by set­tlers for this rea­son as well as for its fur. (Clut­ton-Brock, 1977; Dar­win, 1839; Ren­shaw, 1905)

• Negative Impacts
• injures humans 
   
  • bites or stings 

Con­ser­va­tion Sta­tus

Du­si­cyon aus­tralis is ex­tinct. Dur­ing the 1800's, the species was al­ready in de­cline due to human set­tlers, who killed these wolves for their fur and to pro­tect live­stock. By 1839 Astor's fur hunters had greatly re­duced the num­ber of wolves on the is­lands (Hamil­ton Smith, 1839). By the end of the 19th cen­tury, they were ex­tinct, with the final mem­ber of the species killed most likely in 1876. (Dar­win, 1839; Hamil­ton Smith, 1839; IUCN SSC Canid Spe­cial­ist Group 2008, 2008)

• IUCN Red List

  Extinct

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

Du­si­cyon aus­tralis has pre­sented sci­en­tists with a mys­tery ever since its dis­cov­ery. Many zo­ol­o­gists have won­dered how only one mam­mal species man­aged to ar­rive on the Falk­land Is­lands. How­ever, be­cause they are ex­tinct, spec­i­mens are rare. Al­though Hamil­ton Smith re­ported nu­mer­ous pelts in a New York fur store, these furs have not been found. Only 11 spec­i­mens have been pre­served and very few with skins. Some sci­en­tists sug­gest that these wolves were brought by hu­mans to the is­lands in the last 10,000 years, not­ing that they share many traits with do­mes­ti­cated dogs, such as a white tail tip and a larger frontal bone (Clut­ton-Brock, 1977). A 2009 study by Slater et al. used mol­e­c­u­lar dat­ing to de­ter­mine that the Falk­land Is­lands wolf lin­eage dated to 330,000 years ago, long be­fore hu­mans ar­rived in South Amer­ica (Slater et al, 2009). In ad­di­tion, the study found that Du­si­cyon aus­tralis is most closely re­lated to maned wolves (Chryso­cyon brachyu­rus) and di­verged about 6.7 mya. They sug­gested that Du­si­cyon aus­tralis might have reached the Falk­land Is­lands "by raft­ing or dis­pers­ing over glacial ice dur­ing the late Pleis­tocene." (Clut­ton-Brock, 1977; Hamil­ton Smith, 1839; Slater, et al., 2009b; Slater, et al., 2009a)

Du­si­cyon austalis may have been sev­eral species. Dar­win re­ported that wolves liv­ing on the east­ern and west­ern sides of the arch­i­pel­ago looked slightly dif­fer­ent and were pos­si­ble sep­a­rate species. West­ern Falk­land Is­land wolves were typ­i­cally smaller, with white feet and a longer tail (Hamil­ton Smith, 1839). (Dar­win, 1839; Hamil­ton Smith, 1839)

Du­si­cyon aus­tralis was for­merly known as Antarc­tic wolves, Canis antarcti­cus. (Ren­shaw, 1905)

Con­trib­u­tors

Kather­ine Osh­man (au­thor), Yale Uni­ver­sity, Eric Sar­gis (ed­i­tor), Yale Uni­ver­sity, Rachel Raci­cot (ed­i­tor), Yale Uni­ver­sity, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

diurnal

1. active during the day, 2. lasting for one day.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

Ref­er­ences

2012. "Falk­land Is­land Wolf Photo" (On-line). ARKive. Ac­cessed Feb­ru­ary 15, 2012 at http://​www.​arkive.​org/​falkland-island-wolf/​dusicyon-australis/​image-G42426.​html.

CIA, 2012. "CIA - The World Fact­book" (On-line). Ac­cessed April 07, 2012 at https://​www.​cia.​gov/​library/​publications/​the-world-factbook/​geos/​fk.​html.

Cabr­era, A. 1931. On Some South Amer­i­can Ca­nine Gen­era. Jour­nal of Mam­mal­ogy, 12/1: 54-67. Ac­cessed Feb­ru­ary 15, 2012 at http://​www.​jstor.​org/​stable/​1373806.

Clut­ton-Brock, J. 1977. Man-Made Dogs. Sci­ence, 197: 1340-1342. Ac­cessed April 08, 2012 at http://​www.​ncbi.​nlm.​nih.​gov/​pubmed/​17746990.

Dar­win, C. 1839. Nar­ra­tive of the sur­vey­ing voy­ages of His Majesty's Ships Ad­ven­ture and Bea­gle be­tween the years 1826 and 1836, de­scrib­ing their ex­am­i­na­tion of the south­ern shores of South Amer­ica, and the Bea­gle's cir­cum­nav­i­ga­tion of the globe. Jour­nal and re­marks. 1832-1836. Lon­don: Henry Col­burn. Ac­cessed Feb­ru­ary 15, 2012 at http://​darwin-online.​org.​uk/​content/​frameset?​viewtype=text&​itemID=F10.​3&​pageseq=268.

Falk­land Is­lands Mu­seum and Na­tional Trust, 2012. "The Evans War­rah" (On-line). Ac­cessed April 09, 2012 at http://​www.​falklands-museum.​com/​index.​php?​option=com_​content&​view=article&​id=179&​Itemid=261.

Hamil­ton Smith, C. 1843. Mam­malia: Dogs. Lon­don: Ed­in­burgh.

Hamil­ton Smith, C. 1839. The nat­ural his­tory of dogs: Canidae or genus canis of au­thors. In­clud­ing also the gen­era hyaena and pro­te­les, Vol­ume 9. Lon­don: W.H. Lizars, ... S. High­ley, ... Lon­don; and W. Curry, jun. and Co. Dublin.. Ac­cessed April 27, 2012 at http://​books.​google.​com/​books?​id=4xAAAAAAQAAJ&​printsec=frontcover#​v=onepage&​q&​f=false.

IUCN SSC Canid Spe­cial­ist Group 2008, 2008. "IUCN Red List of Threat­ened Species" (On-line). Du­si­cyon aus­tralis. Ac­cessed Feb­ru­ary 15, 2012 at http://​www.​iucnredlist.​org/​apps/​redlist/​details/​6923/​0.

Lyras, G., A. Van der Geer. 2003. Ex­ter­nal brain anatomy in re­la­tion to the phy­logeny of Can­i­nae (Car­nivora: Canidae). Zo­o­log­i­cal Jour­nal of the Lin­nean So­ci­ety, 138: 505-522. Ac­cessed Feb­ru­ary 15, 2012 at http://​users.​uoa.​gr/​~geer­aae/pub­li­ca­tions/2003-Linnean-Caninaebrain.​pdf.

Os­good, W. 1934. The Gen­era and Sub­gen­era of South Amer­i­can Canids. Jour­nal of Mam­mal­ogy, 15/1: 45-50. Ac­cessed Feb­ru­ary 15, 2012 at http://​www.​jstor.​org/​stable/​1373896.

Ren­shaw, G. 1905. More nat­ural his­tory es­says. Lon­don: Sher­ratt & Hughes. Ac­cessed April 27, 2012 at http://​books.​google.​com/​books?​id=0OAHAQAAIAAJ&​pg=PA77&​lpg=PA77&​dq=Renshaw+%25E2%2580%259CThe+Antarctic+Wolf%25E2%2580%259D&​source=bl&​ots=A0-i5IX5dg&​sig=qo2uXQvFqzJuhxACfTRMl_​ppa6w&​hl=en&​sa=X&​ei=VYSDT7WrC7Cr0AHaw5DzBw&​ved=0CC4Q6AEwAg%23v=onepage&​q=Renshaw%2520%25E2%2580%259CThe%25#​v=onepage&​q=Renshaw%2520%25E2%2580%259CThe%25&​f=false.

Slater, G., O. Thal­mann, J. Leonard, R. Schweizer, K. Koepfli, J. Pollinger, N. Raw­lence, J. Austin, A. Cooper, R. Wayne. 2009. Evo­lu­tion­ary his­tory of the Falk­lands wolf. Cur­rent Bi­ol­ogy, 19/20: R937-R938. Ac­cessed Feb­ru­ary 15, 2012 at http://​www.​cell.​com/​current-biology/​abstract/​S0960-9822%2809%2901695-9.

Slater, G., O. Thal­mann, J. Leonard, R. Schweizer, K. Koepfli, J. Pollinger, N. Raw­lence, J. Austin, A. Cooper, R. Wayne. 2009. Sup­ple­men­tal Data for Slater et al. Cur­rent Bi­ol­ogy, 19/20: R937-R938. Ac­cessed Feb­ru­ary 15, 2012 at http://​www.​cell.​com/​current-biology/​supplemental/​S0960-9822%2809%2901695-9.