Koala
Koala Temporal range:Pleistocene– Recent
Middle | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Infraclass: | Marsupialia |
Order: | Diprotodontia |
Family: | Phascolarctidae |
Genus: | Phascolarctos |
Species: | P. cinereus
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Binomial name | |
Phascolarctos cinereus (Goldfuss,1817)
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Koala range
Native
Introduced
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Synonyms[2]: 45 [3] | |
Thekoala(Phascolarctos cinereus), sometimes called thekoala bear,is anarborealherbivorousmarsupialnative to Australia. It is the onlyextantrepresentative of thefamilyPhascolarctidae.Its closest living relatives are thewombats.The koala is found in coastal areas of the island's eastern and southern regions, inhabitingQueensland,New South Wales,Victoria,andSouth Australia.It is easily recognisable by its stout, tailless body and large head with round, fluffy ears and large, dark nose. The koala has a body length of 60–85 cm (24–33 in) and weighs 4–15 kg (9–33 lb).Furcolour ranges from silver grey to chocolate brown. Koalas from the northern populations are typically smaller and lighter in colour than their counterparts further south. These populations possibly are separatesubspecies,but this is disputed.
Koalas typically inhabit openEucalyptuswoodland, as the leaves of these trees make up most of their diet. This eucalypt diet has low nutritional and caloric content and contains toxic compounds that deter most other mammals from feeding on it. Koalas are largelysedentaryand sleep up to twenty hours a day. They are asocial, only mothersbondto dependent offspring. Adult malescommunicatewith bellows that intimidate rivals and attract mates. Males mark their presence with secretions fromscent glandslocated on their chests. Like other marsupials, koalas give birth to young known asjoeysat a very early stage of development. They crawl into their mothers'pouches,where they live for their first six to seven months. They are fullyweanedaround a year old. Koalas have few natural predators and parasites, but are threatened bypathogenssuch asChlamydiaceaebacteria andkoala retrovirus.
Because of their distinctive appearance, koalas, along withkangaroosandemus,are recognised worldwide assymbols of Australia.They were hunted byIndigenous Australiansand depicted inmythsandcave artfor millennia. The first recorded encounter between a European and a koala was in 1798, and an image of the animal was published in 1810 by naturalistGeorge Perry.BotanistRobert Brownwrote the first detailed scientificdescriptionin 1814, although his work remained unpublished for 180 years. ArtistJohn Gouldillustrated and described the koala, introducing the species to the British public. Further details about the animal's biology were revealed in the 19th century by English scientists. Koalas are listed as avulnerable speciesby theInternational Union for Conservation of Nature.Among the many threats to their existence arehabitat destructioncaused by agriculture, urbanisation, droughts, and associatedbushfires,some related to climate change. In February 2022, the koala was officially listed asendangeredin theAustralian Capital Territory,New South Wales, and Queensland.
Etymology
The word "koala" comes from theDharuggula,meaning'no water'.Although the vowel "u" was originally written in theEnglish orthographyas "oo" (in spellings such ascoolaorkoolah— two syllables), the spelling later became "oa" and the word is now pronounced in three syllables, possibly in error.[4]
Adopted by white settlers, "koala" became one of hundreds ofAboriginal loan words in Australian English,where it was also commonly referred to as "native bear",[5]later "koala bear", for its resemblance to a bear.[6]It is one of several Aboriginal words that made it intoInternational Englishalongside words like "didgeridoo"and"kangaroo".[6]Thegenericname,Phascolarctos,is derived from theGreekwordsφάσκωλος(phaskolos)'pouch'andἄρκτος(arktos)'bear'.Thespecific name,cinereus,isLatinfor'ash coloured'.[7]
Taxonomy
The koala was given its generic namePhascolarctosin 1816 by French zoologistHenri Marie Ducrotay de Blainville,[8]who did not give it a specific name until further review. In 1819, German zoologistGeorg August Goldfussgave it thebinomialLipurus cinereus.BecausePhascolarctoswas published first, according to theInternational Code of Zoological Nomenclature,it haspriorityas the official genus name.[9]: 58–59 French naturalistAnselme Gaëtan Desmarestcoined the namePhascolarctos fuscusin 1820, suggesting that the brown-coloured versions were a different species than the grey ones. Other names suggested by European authors includedMarodactylus cinereusby Goldfuss in 1820,P. flindersiibyRené Primevère Lessonin 1827, andP. koalabyJohn Edward Grayin 1827.[2]: 45
Evolution
The koala is classified withwombats(familyVombatidae) and several extinct families (includingmarsupial tapirs,marsupial lionsandgiant wombats) in the suborderVombatiformeswithin the orderDiprotodontia.[10]The Vombatiformes are asister groupto acladethat includesmacropods(kangaroosandwallabies) andpossums.[11]The koala'slineagepossibly branched off around 40 million years ago during theEocene.[12]
The modern koala is the onlyextantmember ofPhascolarctidae,a family that includes several extinct genera and species. During theOligoceneandMiocene,koalas lived inrainforestsand had broader diets.[13]Some species, such asNimiokoala greystanesiand some species ofPerikoala,were around the same size as the modern koala, while others, such as species ofLitokoala,were one-half to two-thirds its size.[14]Like the modern species, prehistoric koalas had well developed ear structures, which suggests that they also made long-distance vocalisations and had a relatively inactive lifestyle.[13]During the Miocene, the Australian continent began drying out, leading to the decline of rainforests and the spread of openEucalyptuswoodlands. The genusPhascolarctossplit fromLitokoalain the late Miocene,[13][15]and had several adaptations that allowed it to live on a eucalyptus diet: thepalateshifted towards the front of the skull; the upper teeth were lined by thicker bone,molarsbecame relatively low compared to the jaw joint and with more chewing surface; thepterygoid fossashrank;[13]and a largergapseparated theincisorteeth and the molars.[16]: 226
P. cinereusmay have emerged as a dwarf form of thegiant koala(P. stirtoni), following the disappearance of several giant animals in the latePleistocene.A 2008 study questioned this hypothesis, noting thatP. cinereusandP. stirtoniweresympatricduring the mid-late Pleistocene, and that their teeth morphology displayed the major differences.[17]The fossil record of the modern koala extends back at least to the middle Pleistocene.[18]
Molecular relationship between living Diprotodontia families based on Phillips and collages (2023)[19] | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Morphology tree of Phascolarctidae based on Beck and collages (2020)[20] | ||||||||||||||||||||||||||||||||||||||||||||||||
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Genetics and variations
Threesubspeciesare recognised: the Queensland koala (Phascolarctos cinereus adustus,Thomas1923), the New South Wales koala (Phascolarctos cinereus cinereus,Goldfuss 1817), and the Victorian koala (Phascolarctos cinereus victor,Troughton1935). These forms are distinguished bypelagecolour and thickness, body size, and skull shape. The Queensland koala is the smallest, with silver or grey short hairs and a shorter skull. The Victorian koala is the largest, with shaggier, brown fur and a wider skull.[21]: 7 [22]The geographic limits of these variations are based onstate borders,and their status as subspecies is disputed. A 1999 genetic study suggests koalas exist as aclinewithin a singleevolutionarily significant unitwith limitedgene flowbetween local populations.[22]
Other studies have found that koala populations are highlyinbredwith lowgenetic variation.[23][24]Such lowgenetic diversitymay have been caused by population declines during the late Pleistocene.[25]Rivers and roads limit gene flow and contribute to the isolation of southeast Queensland populations.[26]In April 2013, scientists from theAustralian MuseumandQueensland University of Technologyannounced they hadfully sequencedthe koalagenome.[27]
Characteristics
The koala is a robust animal with a large head andvestigialor non-existent tail.[9]: 1 [28]It has a body length of 60–85 cm (24–33 in) and a weight of 4–15 kg (9–33 lb),[28]making it among the largest arboreal marsupials.[29]Koalas from Victoria are twice as heavy as those from Queensland.[21]: 7 The species issexually dimorphic:males are 50% larger than females. Males' noses are more curved[29]and sport chest glands, which are visible as bald patches.[21]: 55 The female'spouch openingis secured by asphincterwhich holds the young in.[30]
The pelage of the koala is denser on the back.[29]Back fur colour varies from light grey to chocolate brown.[9]: 1–2 The belly fur is whitish; on the rump it is mottled whitish and dark.[28]The koala has the most effective insulating back fur of any marsupial and is resilient to wind and rain, while the belly fur can reflect solar radiation.[31]The koala has curved, sharp claws well adapted for climbing trees. The large forepaws have twoopposable digits(the first and second, which are opposable to the other three) that allow them to grip small branches. On the hind paws, the second and third digits arefused,a typical condition for members of theDiprotodontia,and the attached claws (which are still separate) function like a comb.[21]: 5 The animal has a robust skeleton and a short, muscular upper body with relatively long upper limbs that contribute to its ability to climb. The thigh muscles are anchored further down theshinbone,increasing its climbing power.[2]: 183
For a mammal, the koala has adisproportionately small brain,[9]: 81 60% smaller than that of a typicaldiprotodont,weighing only 19.2 g (0.68 oz) on average.[32]The brain's surface is fairly smooth and "primitive".[21]: 52 It does not entirely fill thecranial cavity,unlike most mammals,[9]: 81 and is lightened by large amounts ofcerebrospinal fluid.It is possible that the fluid protects the brain should the animal fall from a tree.[21]: 52–53 The koala's small brain may be an adaptation to the energy restrictions imposed by its diet, which is insufficient to sustain a larger brain.[9]: 81 Its small brain limits its ability to perform complex behaviours. For example, it will not eat plucked eucalyptus leaves on a flat surface, which does not match its feeding routine.[16]: 234
The koala has a broad, dark nose[33]with a good sense of smell, and it is known to sniff the oils of individual branchlets to assess their edibility.[9]: 81 Its relatively small eyes are unusual among marsupials in that the pupils have vertical slits,[29]an adaptation to living on a more vertical plane. Its round ears provide it with good hearing,[33][21]: 6 and it has a well-developedmiddle ear.[13]The koala larynx is located relatively low in the vocal tract and can be pulled further down. They possess unique folds in the velum (soft palate), known as velar vocal folds, in addition to the typicalvocal foldsof the larynx. These features allow the koala to produce deeper sounds than would otherwise be possible for their size.[34][35]
The koala has several adaptations for its low nutrient, toxic, and fibrous diet.[9]: 76 The animal'sdentitionconsists of incisors andcheek teeth(a single premolar and four molars on each jaw) that are separated by a large gap (a characteristic feature of herbivorous mammals). The koala bites a leaf with the incisors and clips it with the premolars at thepetiole,before chewing it to pieces with thecuspedmolars.[21]: 46 Koalas may store food in theircheek pouchesbefore it is ready to be chewed.[36]The partially worn molars of koalas in their prime are optimal for breaking leaves into small particles, resulting in more efficient stomach digestion and nutrient absorption in the small intestine,[16]: 231 which digests the eucalyptus leaves to provide most of the animal's energy.[21]: 47 A koala sometimesregurgitatesthe food into the mouth to be chewed a second time.[37]
Koalas arehindgut fermenters,and their digestive retention can last 100 hours in the wild or 200 hours in captivity.[21]: 48 This is made possible by theircaecum—200 cm (80 in) long and 10 cm (4 in) in diameter—possibly the largest for an animal of its size.[2]: 188 Koalas can retain food particles for longer fermentation if needed. They are more likely keep smaller particles as larger ones take longer to digest.[21]: 48 While the hindgut is relatively large, only 10% of the animal's energy is obtained from digestion in this chamber. The koala'smetabolic rateis only 50% of the typical mammalian rate, owing to its low energy intake,[9]: 77–78 although this can vary across seasons and sexes.[21]: 49 They can digest the toxicplant secondary metabolites,phenolic compoundsandterpenesdue to their production ofcytochrome P450,which neutralises these poisons in theliver.[38]The koala replaces lost water at a lower rate than species such as some possums.[16]: 231 It maintains water by absorbing it in the caecum, resulting in drier faecal pellets packed with undigested fibre.[16]: 231 [2]: 188
Distribution and habitat
The koala's range covers roughly 1,000,000 km2(390,000 sq mi), and 30ecoregions.[39]It ranges throughout mainland eastern and southeastern Australia, including the states of Queensland, New South Wales, Victoria, andSouth Australia.The koala wasintroducedto several nearby islands.[1]The population onMagnetic Islandrepresents the northern limit of its range.[39]
Fossil evidence shows that the koala's range stretched as far west as southwesternWestern Australiaduring the late Pleistocene. They were likely driven to extinction in these areas by environmental changes and hunting byIndigenous Australians.[21]: 12–13 Koalas were introduced to Western Australia atYanchepin 1938 but that population was reduced to 4 individuals by 2022.[40]Koalas can be found in both tropical and temperate habitats ranging from densewoodlandsto more spaced-out forests.[29]Insemi-arid climates,they preferriparian habitats,where nearby streams and creeks provide refuge during times of drought and extreme heat.[41]
Behaviour and ecology
Foraging and activities
Koalas areherbivorous,and while most of their diet consists ofeucalyptleaves, they can be found in trees of other genera, such asAcacia,Allocasuarina,Callitris,Leptospermum,andMelaleuca.[9]: 73 Though the foliage of over 600 species ofEucalyptusis available, the koala shows a strong preference for around 30.[42]They prefer plant matter with higherproteinthan fibre andlignin.[16]: 231 The most favoured species areEucalyptus microcorys,E. tereticornis,andE. camaldulensis,which, on average, make up more than 20% of their diet.[43]Despite its reputation as a picky eater, the koala is moregeneralistthan some other marsupial species, such as thegreater glider.The koala does not need to drink often as it can get enough water from the leaves,[9]: 73–74 though larger males may additionally drink water found on the ground or in tree hollows.[16]: 231 When feeding, a koala reaches out to grab leaves with one forepaw while the other paws hang on to the branch. Depending on the size of the individual, a koala can walk to the end of a branch or must stay near the base.[9]: 96 Each day, koalas eat up to 400 grams (14 oz) of leaves, spread over four to six feeding periods.[2]: 187 Despite their adaptations to a low-energy lifestyle, they have meagrefat reserves.[2]: 189
Their low-energy diet limits their activity and they sleep 20 hours a day.[9]: 93 [44]They are predominantly active at night and spend most of their waking hours foraging. They typically eat and sleep in the same tree, possibly for as long as a day.[21]: 39 On warm days, a koala may rest with its back against a branch or lie down with its limbs dangling.[9]: 93–94 When it gets hot, the koala rests lower in the canopy and near the trunk, where the surface is cooler than the surrounding air.[45]It curls up when it gets cold and wet.[21]: 39 It resorts to a lower, thicker, branch during high winds. While it spends most of the time in the tree, the animal descends to the ground to move to another tree, with either a walking or leaping gait.[9]: 93–94 The koala usually grooms itself with its hind paws, with their double claws, but sometimes uses its forepaws or mouth.[9]: 97–98
Social life
Koalas are asocial and spend just 15 minutes a day on social behaviours. In areas of higher desnity and fewer trees,home rangesare smaller and more clumped.[9]: 98 Koala society appears to consist of "residents" and "transients": the former are mostly adult females and the latter are males. Resident males appear to beterritorialanddominant.[46]The territories of dominant males are found near breeding females, while younger males must wait until they reach full size to challenge for breeding rights.[2]: 191 Adult males occasionally venture outside their home ranges; when they do, dominant ones retain their status.[9]: 99 As a male climbs a new tree, he rubs his chest against it and sometimes dribbles urine. This scent-marking behaviour probably serves as communication, and individuals are known to sniff the bottom of a newly found tree.[21]: 54–56 [47]Chest gland secretions are complex chemical mixtures — about 40 compounds were identified in one analysis — that vary in composition and concentration across season and age.[48]
Adult males communicate with loud bellows — "a long series of deep, snoring inhalations and belching exhalations".[49]Because of their lowfrequency,these bellows can travel far through the forest.[21]: 56 Koalas may bellow at any time, particularly during thebreeding season,when it serves to attract females and possibly intimidate other males.[50]They also bellow to advertise their presence when they change trees.[21]: 57 These sounds signal and exaggerate the male's body size;[51]females pay more attention to bellows by larger males.[52]Female koalas bellow, though more softly, in addition to making snarls, wails, and screams. These calls are produced when in distress and when making defensive threats.[49]Younger animals squeak and older ones squawk when distraught. When another individual climbs over it, a koala makes a low closed-mouth grunt.[9]: 102–03 [49]Koalas also communicate with facial expressions. When snarling, wailing, or squawking, the animal curls the upper lip and points its ears forward. Screaming koalas pull their lips and ears back. Females form an oval shape with their lips when annoyed.[9]: 104–05
Agonistic behaviourtypically consists of quarrels between individuals who are trying to pass each other on a tree. This occasionally involves biting. Strangers may wrestle, chase, and bite.[9]: 102 [53]In extreme situations, a larger male may try to displace a smaller rival from a tree, chasing, cornering and biting it. Once the individual is driven away, the victor bellows and marks the tree.[9]: 101–02 Pregnant andlactatingfemales are particularly aggressive and attack individuals who come too close.[53]In general, however, koalas tend to avoid fighting due to energy costs.[2]: 191
Reproduction and development
Koalas are seasonal breeders, and give birth from October to May. Females inoestruslean their heads back and shake their bodies. Despite these obvious signals, males try to copulate with any female during this period, mounting them from behind. Because of his much larger size, a male can overpower a female. A female may scream and vigorously fight off her suitors but will accede to one that is dominant or familiar. The commotion can attract other males to the scene, obliging the incumbent to delay mating and fight off the intruders. A female may learn who is more dominant during these fights.[21]: 58–60 Older males typically accumulate scratches, scars, and cuts on the exposed parts of their noses and their eyelids.[2]: 192
Koalas areinduced ovulators.[54]Thegestationperiod lasts 33–35 days,[55]and a female gives birth to onejoeyor occasionally, twins. The young are born tiny and barely formed, weighing no more than 0.5 g (0.02 oz). However, their lips, forelimbs, and shoulders are relatively advanced, and they can breathe, defecate and urinate. The joey crawls into its mother's pouch to continue its development.[21]: 61 Female koalas do not clean their pouches, an unusual trait among marsupials.[2]: 181
The joey latches on to one of the female's two teats and suckles it.[21]: 61 The femalelactatesfor as long as a year to make up for her low energy production. Unlike in other marsupials, koala milk becomes less fatty as the joey grows.[21]: 62 After seven weeks, the joey has a proportionally large head, clear edges around its face, more colouration, and a visible pouch (if female) or scrotum (male). At 13 weeks, the joey weighs around 50 g (1.8 oz) and its head doubles in size. The eyes begin to open and hair begins to appear. At 26 weeks, the fully furred animal resembles an adult and can look outside the pouch.[21]: 63
At six or seven months, the joey weighs 300–500 g (11–18 oz) and fully emerges from the pouch for the first time. It explores its new surroundings cautiously, clutching its mother for support.[21]: 65 Around this time, the mother prepares it for a eucalyptus diet by producing a faecal pap that the joey eats from her cloaca. This pap comes from the cecum, is more liquid than regular faeces, and is filled with bacteria.[56]A nine month old joey has its adult coat colour and weighs 1 kg (2.2 lb). Having permanently left the pouch, it rides on its mother's back for transportation, learning to climb by grasping branches.[21]: 65–66 Gradually, it becomes more independent. The mother becomes pregnant again after a year, when the offspring reaches around 2.5 kg (5.5 lb). She permanently severs her bond with her previous offspring and no longer allows it to suckle, but it remains nearby until it is one-and-a-half to two years old.[21]: 66–67
Females becomesexually matureat about three years of age; in comparison, males reach sexual maturity at about age four,[57]although they can experiencespermatogenesisas early as two years.[21]: 68 Males do not start marking their scent until they reach sexual maturity, though their chest glands become functional much earlier.[48]Koalas can breed every year if environmental conditions are good, though the long dependence of the young usually leads to year-long gaps in births.[16]: 236
Health and mortality
Koalas live from 13 to 18 years in the wild, although males may die sooner because of their more risky lives.[21]: 69 Koalas usually survive falls from trees, but they can get hurt and even die, particularly inexperienced young and fighting males.[21]: 72–73 Around age six, the koala's chewing teeth begin to wear down and their chewing efficiency decreases. Eventually, the cusps disappear completely and the animal dies of starvation.[58]Koalas have few predators.Dingosand largePython sand somebirds of preymay take them. Koalas are generally not subject to externalparasites,other thanticksaround the coast. ThemiteSarcoptes scabieigives koalasmange,while the bacteriumMycobacterium ulceransskin ulcers,but these are uncommon. Internal parasites are few and have little effect.[21]: 71–74 These include theBertiella obesatapeworm,commonly found in the intestine, and theMarsupostrongylus longilarvatusandDurikainema phascolarctinematodes,which are infrequently found in the lungs.[59]In a three-year study of almost 600 koalas taken to the Australia Zoo Wildlife Hospital in Queensland, 73.8% of the animals were infected with parasiticprotozoalgenusTrypanosoma,the most frequent of which wasT. irwini.[60]
Koalas can be subject topathogenssuch asChlamydiaceaebacteria,[21]: 74–75 which can causekeratoconjunctivitis,urinary tract infection,andreproductive tract infection.[9]: 229–30 Such infections are common on the mainland, but absent in some island populations.[21]: 114 Thekoala retrovirus(KoRV) may cause koala immune deficiency syndrome (KIDS) which is similar to AIDS in humans.Prevalenceof KoRV in koala populations suggests it spread from north to south, as only southern populations have virus-free individuals.[61]
The animals are vulnerable tobushfiresdue to their slow speed and theflammability of eucalypt trees.[21]: 26 The koala instinctively seeks refuge in the higher branches, where it is vulnerable to heat and fire. Bushfires divide the animal's habitat, which isolates them, decreases their numbers and createsgenetic bottlenecks.[2]: 209–11 Dehydrationand overheating can prove fatal.[9]: 80 Consequently, the koala is vulnerable to theeffects of climate change.Modelsofclimate changepredict warmer and drier climates, suggesting that the koala's range will shrink in the east and south to moremesic habitats.[62]
Relation to humans
History
The first written reference to the koala was recorded by John Price, servant ofJohn Hunter,theGovernor of New South Wales.Price encountered the "cullawine" on 26 January 1798, during an expedition to theBlue Mountains,[63]but his remarks would first be published inHistorical Records of Australia,nearly a century later.[2]: 8 In 1802, French-born explorerFrancis Louis Barrallierencountered the animal when his two Aboriginal guides, returning from a hunt, brought back two koala feet they were intending to eat. Barrallier preserved the appendages and sent them and his notes to Hunter's successor,Philip Gidley King,who forwarded them toJoseph Banks.Similar to Price, Barrallier's notes were not published until 1897.[2]: 9–10 Reports of the "Koolah" appeared in the Sydney Gazette in late 1803, and helped provide the impetus for King to send artistJohn Lewinto create watercolours of the animal. Lewin painted three pictures, one of which wasprinted inGeorges Cuvier'sLe Règne Animal(The Animal Kingdom)(1827).[2]: 12–13
BotanistRobert Brownwas the first to write a formal scientific description in 1803, based on a female specimen captured near what is nowMount Kemblain theIllawarraregion of New South Wales. Austrian botanical illustratorFerdinand Bauerdrew the animal's skull, throat, feet, and paws. Brown's work remained unpublished and largely unnoticed, however; his field books and notes remained in his possession until his death, when they were bequeathed to theBritish Museumin London. They were not identified until 1994, while Bauer's koala watercolours were not published until 1989.[2]: 16–28 William Paterson,who had befriended Brown and Bauer during their stay in New South Wales, wrote an eyewitness report of his encounters with the animals and this would be the basis for British surgeonEverard Home's anatomical writings on them.[2]: 33–36 Home, who in 1808 published his report,[64]coined the scientific nameDidelphis coola.[2]: 36
George Perryofficially published the first image of the koala in his 1810 natural history workArcana.[2]: 37 Perry called it the "New Holland Sloth", and his dislike for the koala, evident in his description of the animal, was reflected in the contemporary British attitudes towards Australian animals as strange and primitive:[2]: 40
... the eye is placed like that of the Sloth, very close to the mouth and nose, which gives it a clumsy awkward appearance, and void of elegance in the combination... they have little either in their character or appearance to interest the Naturalist or Philosopher. As Nature however provides nothing in vain, we may suppose that even these torpid, senseless creatures are wisely intended to fill up one of the great links of the chain of animated nature...[65]
Naturalist and popular artistJohn Gouldillustrated and described the koala in his three-volume workThe Mammals of Australia(1845–1863) and introduced the species, as well as other members of Australia's little-known faunal community, to the public.[2]: 87–93 Comparative anatomistRichard Owen,in a series of publications on the physiology and anatomy of Australian mammals, presented a paper on the anatomy of the koala to theZoological Society of London.[66]In this widely cited publication, he provided an early description of its internal anatomy, and noted its general structural similarity to the wombat.[2]: 94–96 English naturalistGeorge Robert Waterhouse,curator of the Zoological Society of London, was the first to correctly classify the koala as a marsupial in the 1840s, and compared it to fossil speciesDiprotodonandNototherium,which had been discovered just recently.[2]: 46–48 Similarly,Gerard Krefft,curator of theAustralian Museumin Sydney, notedevolutionarymechanisms at work when comparing the koala to fossil marsupials in his 1871The Mammals of Australia.[2]: 103–105
Britain received its first living koala in 1881, which was obtained by theZoological Society of London.As related by prosecutor to the society,William Alexander Forbes,the animal suffered an accidental demise when the heavy lid of awashstandfell on it and it was unable to free itself. Forbes dissected the specimen and wrote about the female reproductive system, the brain, and the liver — parts not previously described by Owen, who had access only to preserved specimens.[2]: 105–06 ScottishembryologistWilliam Caldwell— well known in scientific circles for determining the reproductive mechanism of theplatypus— described the uterine development of the koala in 1884,[67]and used this new information to convincingly map out the evolutionary timeline of the koala and themonotremes.[2]: 111
Culture
The koala is known worldwide and is a major draw for Australian zoos and wildlife parks. It has been featured in popular culture and assoft toys.[9]: ix It benefited the Australian tourism industry by over $1 billion in 1998, and subsequently grown.[2]: 201 Its international popularly rose afterWorld War II,whentourismincreased and the animals were exported to zoos overseas.[9]: 156 In 1997, about 75% of European and Japanese tourists placed the koala at the top of their list of animals to see.[2]: 216 According to biologist Stephen Jackson: "If you were to take a straw poll of the animal most closely associated with Australia, it's a fair bet that the koala would come out marginally in front of the kangaroo".[9]: ix Factors that contribute to the koala's enduring popularity include itsteddy bear-like appearance with childlike body proportions.[21]: 3
The koala features in theDreamtimestories andmythologyof Indigenous Australians. TheTharawal peoplebelieved that the animal helped them get to Australia by rowing the boat.[9]: 21 Another myth tells of a tribe that killed a koala and used its long intestines to create a bridge for people from other parts of the world.[21]: 17 How the koala lost its tail is the subject of many tales. In one, a kangaroo cuts it off to punish the koala for uncouth behaviour.[9]: 28 Tribes in Queensland and Victoria regarded the koala as a wise animal that gave valuable guidance.Bidjara-speaking people credited the koala for making trees grow in their arid lands.[9]: 41–43 The animal is depicted inrock carvings,though less so than some other species.[9]: 45–46
Early European settlers in Australia considered the koala to be a creepingsloth-like animal with a "fierce and menacing look".[9]: 143 At the turn of the 20th century, the koala's reputation took a positive turn. It appears inEthel Pedley's 1899 bookDot and the Kangaroo,as the "funny native bear".[9]: 144 ArtistNorman Lindsaydepicted a moreanthropomorphickoala inThe Bulletincartoons, starting in 1904. This character also appeared as Bunyip Bluegum in Lindsay's 1918 bookThe Magic Pudding.[9]: 147 The most well known fictional koala isBlinky Bill.Created byDorothy Wallin 1933, the character appeared in books, films, TV series, merchandise, and a 1986 environmental song byJohn Williamson.[9]: 149–52 The koala first appeared on anAustralian stampin 1930.[2]: 164
The song "Ode to a Koala Bear" appears on theB-sideof the 1983Paul McCartney/Michael Jacksonduet singleSay Say Say.[9]: 151 A koala is the main character in animated cartoons in the early 1980s:Hanna-Barbera'sThe Kwicky Koala ShowandNippon Animation'sNoozles.Food products shaped like the koala include theCaramello Koalachocolate bar and the bite-sized cookie snackKoala's March.Dadswells Bridgein Victoria features a tourist complex shaped like a giant koala[9]: 155–58 and theQueensland Redsrugby team has a koala as its icon.[9]: 160
Koala diplomacy
Political leaders and members of royal families had their pictures taken with koalas, includingQueen Elizabeth II,Prince Harry,Crown Prince Naruhito,Crown Princess Masako,Pope John Paul II,US PresidentBill Clinton,Soviet premierMikhail Gorbachevand South African PresidentNelson Mandela[9]: 156 At the2014 G20 Brisbane summit,hosted by Prime MinisterTony Abbott,many world leaders, including Russian PresidentVladimir Putinand US PresidentBarack Obama,were photographed holding koalas.[68][69]The event gave rise to the term "koala diplomacy",[70][71]which became the Oxford Word of the Month for December 2016.[72]The term also includes the loan of koalas by the Australian government to overseas zoos in countries such as Singapore and Japan, as a form of "soft power diplomacy", like the "panda diplomacy"practised by China.[73][74]
Conservation
The koala was originally classified asLeast Concernon theRed List,and reassessed asVulnerablein 2014.[1]In the Australian Capital Territory, New South Wales and Queensland, the species was listed under the EPBC Act in February 2022 as endangered by extinction.[75][76]The described population was determined in 2012 to be "a species for the purposes of the EPBC Act 1999" in Federal legislation.[77]
Australian policymakers declined a 2009 proposal to include the koala in theEnvironment Protection and Biodiversity Conservation Act 1999.[18]A 2017WWFreport found a 53% decline per generation in Queensland, and a 26% decline in New South Wales.[78]The koala population in South Australia and Victoria appear to be abundant; however, theAustralian Koala Foundation(AKF) argued that the exclusion of Victorian populations from protective measures was based on a misconception that the total population was 200,000, whereas they believed in 2012 that it was probably less than 100,000.[79]AKF estimated in 2022 that there could be 43,000–100,000.[80]This compares with 8 to 10 million at the start of the 20th century.[81][82]The Australian Government's Threatened Species Scientific Committee estimated that the 2021 koala population was 92,000, down from 185,000 two decades prior.[83]
The koala was heavily hunted by European settlers in the early 20th century,[2]: 121–128 largely for its fur. Australia exported as many as two million pelts by 1924. Koala furs were used to make rugs, coat linings,muffs,and on women's garment trimmings.[2]: 125 The first successful efforts at conserving the species were initiated by the establishment of Brisbane'sLone Pine Koala Sanctuaryand Sydney'sKoala Park Sanctuaryin the 1920s and 1930s. Its owner Noel Burnet created the first successful breeding program.[2]: 157–159
One of the biggestanthropogenicthreats to the koala ishabitat destructionandfragmentation.Near the coast, the main cause of this is urbanisation, while in rural areas, habitat iscleared for agriculture.Its favoured trees are harvested for wood products.[21]: 104–107 In 2000, Australia had the fifth highest rate of land clearance globally, stripping 564,800 hectares (1,396,000 acres) of native plants.[9]: 222 The koalas' distribution has shrunk by more than 50% since European arrival, largely due to habitat fragmentation in Queensland.[39]Nevertheless, koalas live in manyprotected areas.[1]
While urbanisation can pose a threat to koala populations, the animals can survive in urban areas given enough trees.[84]Urban populations have distinct vulnerabilities:collisions with vehiclesand attacks by domestic dogs.[85]Cars and dogs kill about 4,000 animals every year.[86]To reduce road deaths, government agencies have been exploring variouswildlife crossingoptions,[87][88]such as the use of fencing to channel animals toward an underpass, in some cases adding a walkway to an existing culvert.[89][90]Injured koalas are often taken to wildlife hospitals andrehabilitation centres.[84]In a 30-yearretrospective studyperformed at a New South Wales koala rehabilitation centre,traumawas found to be the most frequent cause of admission, followed by symptoms ofChlamydiainfection.[91]
See also
- Drop bear– A predatory and dangerous version of the koala in popular folklore
- Fauna of Australia
- List of monotremes and marsupials of Australia
- Sam (koala),a female koala known for being rescued during theBlack Saturday bushfiresin 2009
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- ^How to keep koalas off the road - Koala Vehicle Strike Fact sheet 2(PDF).June 2020.ISBN978-1-922431-20-2.Archived(PDF)from the original on 22 April 2021.Retrieved22 April2021– via NSW Government.
- ^"Koalas and resilient habitat in the Sutherland Shire".Sutherland Shire Environment Centre.September 2021.Archivedfrom the original on 22 April 2021.Retrieved22 April2021.
- ^Moore, Tony (26 July 2016)."Koalas tunnels and bridges prove effective on busy roads".Brisbane Times.Archivedfrom the original on 22 April 2021.Retrieved22 April2021.
- ^"Clever koalas learn to cross the road safely".BBC News.27 July 2016.Archivedfrom the original on 22 April 2021.Retrieved22 April2021.
- ^Griffith, J. E.; Dhand, N. K.; Krockenberger, M. B.; Higgins, D. P. (2013)."A retrospective study of admission trends of koalas to a rehabilitation facility over 30 years"(PDF).Journal of Wildlife Diseases.49(1): 18–28.doi:10.7589/2012-05-135.hdl:2123/14628.PMID23307368.S2CID32878079.Archived(PDF)from the original on 21 July 2018.Retrieved24 September2019.
External links
- Archive –images and movies of the koalaPhascolarctos cinereus
- Animal Diversity Web –Phascolarctos cinereus
- iNaturalist crowdsourcedkoala sighting photos(mapped, graphed)
- Koala Science CommunityArchived5 May 2020 at theWayback Machine
- "Koala Crunch Time"– anABCdocumentary (2012)
- "Koalas deserve full protection"
- Cracking the Koala Code– aPBS Naturedocumentary (2012)
- The Aussie Koala Ark Conservation ProjectArchived12 May 2021 at theWayback Machine
- IUCN Red List vulnerable species
- Koalas
- Clawed herbivores
- Extant Middle Pleistocene first appearances
- Herbivorous mammals
- Mammals described in 1817
- Mammals of New South Wales
- Mammals of Queensland
- Mammals of South Australia
- Mammals of Victoria (state)
- Marsupials of Australia
- Vombatiforms
- Symbols of Queensland
- Taxa named by Georg August Goldfuss