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{{other uses}}{{pp-vandalism|small=yes}}{{pp-move-indef}}{{short description|A semi-aquatic egg-laying mammal from eastern Australia }}{{Use Australian English|date=February 2012}}{{Use dmy dates|date=March 2015}}{{speciesbox
id = 10300020 | page = 2}}9|0}} Miocene to Recent| image = Wild Platypus 4.jpg| image_upright = 1.1| status = NT| status_system = IUCN3.1ORNITHORHYNCHUS ANATINUS > JOURNAL = IUCN RED LIST OF THREATENED SPECIES PAGE = E.T40488A21964009 DOI = 10.2305/IUCN.UK.2016-1.RLTS.T40488A21964009.EN, | taxon = Ornithorhynchus anatinusJohann Friedrich Blumenbach>Blumenbach, 1800George Shaw>Shaw, 1799)| range_map = Distribution of the Platypus (Ornithorhynchus anatinus).png| range_map_caption = Platypus range(red — native, yellow — introduced)}}The platypus (Ornithorhynchus anatinus), sometimes referred to as the duck-billed platypus, is a semiaquatic egg-laying mammalJOURNAL, MacFarlane, P. M., Baudinette, R. V., Frappell, P. B., Fish, F. E., 2001-02-15, Energetics of terrestrial locomotion of the platypus Ornithorhynchus anatinus,weblink Journal of Experimental Biology, en, 204, 4, 797–803, 0022-0949, 11171362, endemic to eastern Australia, including Tasmania. The platypus is the sole living representative of its family (Ornithorhynchidae) and genus (Ornithorhynchus), though a number of related species appear in the fossil record.Together with the four species of echidna, it is one of the five (wikt:extant|extant) species of monotremes, the only mammals that lay eggs instead of giving birth to live young. Like other monotremes it senses prey through electrolocation. It is one of the few species of venomous mammals, as the male platypus has a spur on the hind foot that delivers a venom capable of causing severe pain to humans.The unusual appearance of this egg-laying, duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, and the first scientists to examine a preserved platypus body (in 1799)WEB,weblink November 29, 2016, Discovery and naming, Australian Platypus Conservancy, judged it a fake, made of several animals sewn together. BOOK, Encyclopedia of Animals, Walters, Martin, Johnson, Jinny, Marks and Spencer p.l.c, 2003, 978-1-84273-964-8, 192, The unique features of the platypus make it an important subject in the study of evolutionary biology, and a recognizable and iconic symbol of Australia. It has appeared as a mascot at national events and features on the reverse of the Australian twenty-cent coin, and the platypus is the animal emblem of the state of New South Wales. WEB,weblink Government of New South Wales, Symbols & Emblems of NSW, 2008, 29 December 2008,weblink" title="">weblink 23 July 2008, yes, Government of New South Wales, Until the early 20th century humans hunted the platypus for its fur, but it is now protected throughout its range. Although captive-breeding programs have had only limited success, and the platypus is vulnerable to the effects of pollution, it is not under any immediate threat.

Taxonomy and etymology

(File:Platypus (Ornithorhynchus anatinus). First Description 1799.jpg|thumb|Platypus (Ornithorhynchus anatinus). First Description 1799)When the platypus was first encountered by Europeans in 1798, a pelt and sketch were sent back to Great Britain by Captain John Hunter, the second Governor of New South Wales.JOURNAL, BioScience, 1313511, The Paradoxical Platypus, Brian K., Hall, 49, 3, 211–8, March 1999, 10.2307/1313511, British scientists' initial hunch was that the attributes were a hoax.WEB,weblink Duck-billed Platypus, Museum of hoaxes, 21 July 2010, George Shaw, who produced the first description of the animal in the Naturalist's Miscellany in 1799, stated it was impossible not to entertain doubts as to its genuine nature,BOOK, Shaw, George, Naturalist's Miscellany, vol.10, 1799, 227–232,weblink
publisher=London : Printed for Nodder & co, and Robert Knox believed it might have been produced by some Asian Taxidermy. It was thought that somebody had sewn a duck's beak onto the body of a beaver-like animal. Shaw even took a pair of scissors to the dried skin to check for stitches.HTTP://WWW.PLATYPUS.ASN.AU/PUBLISHER=AUSTRALIAN PLATYPUS CONSERVANCY, 13 September 2006, The common name "platypus" is the latinisation of the Greek word ({{transl|grc|platupous}}), "flat-footed",πλατύπους, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus from ({{transl|grc|platus}}), "broad, wide, flat"πλατύς, A Greek-English Lexicon, on Perseus and ({{transl|grc|pous}}), "foot".πούς, A Greek-English Lexicon, on PerseusBOOK, Liddell, Henry George, Scott, Robert, yes, 1980, Greek-English Lexicon, Abridged Edition, Oxford University Press, Oxford, UK, 978-0-19-910207-5, Shaw assigned the species the Linnaean name Platypus anatinus when he initially described it, but the genus term was quickly discovered to already be in use as the name of the wood-boring ambrosia beetle genus Platypus.BOOK,weblink Fauna of Australia, 16, 1b, J.R., Grant, Australian Biological Resources Study (ABRS), 13 September 2006, bot: unknown,weblink" title="">weblink 19 May 2005, It was independently described as Ornithorhynchus paradoxus by Johann Blumenbach in 1800 (from a specimen given to him by Sir Joseph Banks)WEB,weblink Platypus Paradoxes, National Library of Australia, August 2001, 14 September 2006, and following the rules of priority of nomenclature, it was later officially recognised as Ornithorhynchus anatinus.The scientific name Ornithorhynchus anatinus is derived from ({{transl|grc|ornithorhynkhos}}), which literally means "bird snout" in Greek; and anatinus, which means "duck-like" in Latin.There is no universally-agreed plural form of "platypus" in the English language. Scientists generally use "platypuses" or simply "platypus". Colloquially, the term "platypi" is also used for the plural, although this is technically incorrect and a form of pseudo-Latin; the correct Greek plural would be "platypodes". Early British settlers called it by many names, such as "watermole", "duckbill", and "duckmole". The name platypus is occasionally prefixed with the adjective "duck-billed" to form duck-billed platypus.


File:Schnabeltier 1.jpg|thumb|Platypus in Broken River, Queensland ]]In David Collins's account of the new colony 1788–1801, he describes coming across "an amphibious animal, of the mole species". His account includes a drawing of the animal.BOOK,weblink An Account of the English Colony in New South Wales, Volume 2, David, Collins, 5 July 2017, Internet Archive, The body and the broad, flat tail of the platypus are covered with dense, brown fur that traps a layer of insulating air to keep the animal warm. The fur is waterproof, and the texture is akin to that of a mole.WEB,weblink Platypus : Facts, Pictures : Animal Planet,, 16 November 2011, 8 September 2012, The platypus uses its tail for storage of fat reserves (an adaptation also found in animals such as the Tasmanian devilBOOK, Guiler, E.R., 1983, Tasmanian Devil, R. Strahan, The Australian Museum Complete Book of Australian Mammals, 27–28, Angus & Robertson, 978-0-207-14454-7, ). The webbing on the feet is more significant on the front feet and is folded back when walking on land. The elongated snout and lower jaw are covered in soft skin, forming the bill. The nostrils are located on the dorsal surface of the snout, while the eyes and ears are located in a groove set just back from it; this groove is closed when swimming. Platypuses have been heard to emit a low growl when disturbed and a range of other vocalisations have been reported in captive specimens.(File:platypus-sketch.jpg|left|thumb|A colour print of platypuses from 1863)Weight varies considerably from {{convert|0.7|to|2.4|kg|lb|abbr=on}}, with males being larger than females; males average {{convert|50|cm|in|abbr=on}} in total length, while females average {{convert|43|cm|in|abbr=on}}, with substantial variation in average size from one region to another, and this pattern does not seem to follow any particular climatic rule and may be due to other environmental factors, such as predation and human encroachment.WEB,weblink Current research on the platypus, Ornithorhynchus anatinus in Tasmania: Abstracts from the 1999 'Tasmanian Platypus WORKSHOP', Munks, Sarah, Nicol, Stewart, yes, University of Tasmania, May 1999, 23 October 2006,weblink" title="">weblink 30 August 2006, yes, The platypus has an average body temperature of about {{convert|32|C|F}} rather than the {{convert|37|C|F}} typical of placental mammals.WEB,weblink Thermal Biology of the Platypus, Davidson College, 1999, 14 September 2006, yes,weblink" title="">weblink 6 March 2012, Research suggests this has been a gradual adaptation to harsh environmental conditions on the part of the small number of surviving monotreme species rather than a historical characteristic of monotremes.JOURNAL, Australian Journal of Zoology, Monotreme Cell-Cycles and the Evolution of Homeothermy, Watson, J.M., Graves, J.A.M., 36, 5, 573–584, 1988, 10.1071/ZO9880573, JOURNAL, Australian Journal of Zoology, Standard Metabolism of Monotremes and the Evolution of Homeothermy, Dawson, T.J., Grant, T.R., Fanning, D., 27, 4, 511–5, 1979, 10.1071/ZO9790511, Modern platypus young have three teeth in each of the maxillae (one premolar and two molars) and dentaries (three molars), which they lose before or just after leaving the breeding burrow; adults have heavily keratinised pads in their place. The first upper and third lower cheek teeth of platypus nestlings are small, each having one principal cusp, while the other teeth have two main cusps.BOOK, Peter S., Ungar, Mammal Teeth: Origin, Evolution, and Diversity, Monotremata and Marsupialia, The Johns Hopkins University Press, 130, 2010, 978-0-801-89668-2, The platypus jaw is constructed differently from that of other mammals, and the jaw-opening muscle is different. As in all true mammals, the tiny bones that conduct sound in the middle ear are fully incorporated into the skull, rather than lying in the jaw as in cynodonts and other premammalian synapsids. However, the external opening of the ear still lies at the base of the jaw. The platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammals. As in many other aquatic and semiaquatic vertebrates, the bones show osteosclerosis, increasing their density to provide ballast.JOURNAL, 10.1371/journal.pone.0059146, 23565143, 3615000, Bone Inner Structure Suggests Increasing Aquatic Adaptations in Desmostylia (Mammalia, Afrotheria), PLoS ONE, 8, 4, e59146, 2013, Hayashi, S., Houssaye, A., Nakajima, Y., Chiba, K., Ando, T., Sawamura, H., Inuzuka, N., Kaneko, N., Osaki, T., 2013PLoSO...859146H, It has a reptilian gait, with the legs on the sides of the body, rather than underneath. When on land, it engages in knuckle-walking on its front feet, to protect the webbing between the toes.JOURNAL, Fish FE, Frappell PB, Baudinette RV, MacFarlane PM, Energetics of terrestrial locomotion of the platypus Ornithorhynchus anatinus, J. Exp. Biol., 204, Pt 4, 797–803, February 2001, 11171362,weblink


(File:Platypus spur.JPG|right|thumb|The calcaneus spur found on the male's hind limb is used to deliver venom.)While both male and female platypuses are born with ankle spurs, only the male's spurs deliver venom,WEB,weblink Australian Fauna, Australian Fauna, 14 May 2010, yes,weblink" title="">weblink 29 May 2012, dmy-all, WEB,weblink Platypus venom linked to pain relief, University of Sydney, 8 May 2008, 14 May 2010, WEB,weblink Platypus poison, Rainforest Australia, 14 May 2010, yes,weblink" title="">weblink 29 May 2010, dmy-all, composed largely of defensin-like proteins (DLPs), three of which are unique to the platypus.JOURNAL, Gerritsen, Vivienne Baillie, Platypus poison, Protein Spotlight, 29, December 2002,weblink 14 September 2006, The DLPs are produced by the immune system of the platypus. The function of defensins is to cause lysis in pathogenic bacteria and viruses, but in platypuses they also are formed into venom for defense. Although powerful enough to kill smaller animals such as dogs, the venom is not lethal to humans, but the pain is so excruciating that the victim may be incapacitated.Weimann, Anya (4 July 2007) weblink" title="">Evolution of platypus venom revealed. Cosmos. Oedema rapidly develops around the wound and gradually spreads throughout the affected limb. Information obtained from case histories and anecdotal evidence indicates the pain develops into a long-lasting hyperalgesia (a heightened sensitivity to pain) that persists for days or even months.JOURNAL, Journal of Neurophysiology, Venom From the Platypus, Ornithorhynchus anatinus, Induces a Calcium-Dependent Current in Cultured Dorsal Root Ganglion Cells, de Plater, G.M., Milburn, P.J., Martin, R.L., 85, 3, 1340–5, 2001, 11248005, 10.1152/jn.2001.85.3.1340, WEB,weblink The venom of the platypus (Ornithorhynchus anatinus), 13 September 2006, yes,weblink" title="">weblink 1 February 2012, Venom is produced in the (wikt:crural|crural) glands of the male, which are kidney-shaped alveolar glands connected by a thin-walled duct to a calcaneus spur on each hind limb. The female platypus, in common with echidnas, has rudimentary spur buds that do not develop (dropping off before the end of their first year) and lack functional crural glands.The venom appears to have a different function from those produced by nonmammalian species; its effects are not life-threatening to humans, but nevertheless powerful enough to seriously impair the victim. Since only males produce venom and production rises during the breeding season, it may be used as an offensive weapon to assert dominance during this period.Similar spurs are found on many archaic mammal groups, indicating that this is an ancient characteristic for mammals as a whole, and not exclusive to the platypus or other monotremes.Jørn H. Hurum, Zhe-Xi Luo, and Zofia Kielan-Jaworowska, Were mammals originally venomous?, Acta Palaeontologica Polonica 51 (1), 2006: 1–11


(File:Platypus in Geelong.jpg|thumb|Platypus shown to children.)Monotremes (for the other species, see Echidna) are the only mammals (apart from at least one species of dolphin)NEWS, Black, Richard, Dolphin hunts with electric sense,weblink BBC News, 26 July 2011, 26 December 2012, known to have a sense of electroreception: they locate their prey in part by detecting electric fields generated by muscular contractions. The platypus's electroreception is the most sensitive of any monotreme.JOURNAL, 10.1098/rstb.1998.0275
first1 = Uwelast2=Gregory last3=Iggo, Sensory receptors in monotremes, Philosophical Transactions of the Royal Society of London, 1187–98, 1372, 1998 pmc = 1692308, 353, JOURNAL, Pettigrew, John D., Electroreception in Monotremes, The Journal of Experimental Biology, 1447–54, Pt 10, 1999,weblink 10210685, 202, The electroreceptors are located in rostrocaudal rows in the skin of the bill, while mechanoreceptors (which detect touch) are uniformly distributed across the bill. The electrosensory area of the cerebral cortex is contained within the tactile somatosensory area, and some cortical cells receive input from both electroreceptors and mechanoreceptors, suggesting a close association between the tactile and electric senses. Both electroreceptors and mechanoreceptors in the bill dominate the somatotopic map of the platypus brain, in the same way human hands dominate the Penfield homunculus map.JOURNAL, Pettigrew, John D.last2=Manger last3=Fine, The sensory world of the platypus, Philosophical Transactions of the Royal Society of London, 1199–1210, 1372, 1998 pmc = 1692312, 10.1098/rstb.1998.0276, 353, BOOK, Richard, Dawkins, Richard Dawkins, The Ancestor's Tale, A Pilgrimage to the Dawn of Life, The Duckbill's Tale, Houghton Mifflin, Boston MA, 2004 title-link = The Ancestor's Tale, The platypus can determine the direction of an electric source, perhaps by comparing differences in signal strength across the sheet of electroreceptors. This would explain the characteristic side-to-side motion of the animal's head while hunting, seen also in the Hammerhead shark while foraging. The cortical convergence of electrosensory and tactile inputs suggests a mechanism that determines the distance of prey that, when they move, emit both electrical signals and mechanical pressure pulses. The platypus uses the difference between arrival times of the two signals to sense distance.Feeding by neither sight nor smell, the platypus closes its eyes, ears, and nose each time it dives.JOURNAL, Gregory, J.E., Iggo, A., McIntyre, A.K., Proske, U., Receptors in the Bill of the Platypus, 1191811, Journal of Physiology, 400, 1, 349–366, June 1988, 3418529, 10.1113/jphysiol.1988.sp017124, Rather, when it digs in the bottom of streams with its bill, its electroreceptors detect tiny electric currents generated by muscular contractions of its prey, so enabling it to distinguish between animate and inanimate objects, which continuously stimulate its mechanoreceptors. Experiments have shown the platypus will even react to an "artificial shrimp" if a small electric current is passed through it.BOOK, Manning, A., Dawkins, M.S., An Introduction to Animal Behaviour, 5th, Cambridge University Press, 1998, Monotreme electrolocation probably evolved in order to allow the animals to forage in murky waters, and may be tied to their tooth loss.Masakazu Asahara; Masahiro Koizumi; Thomas E. Macrini; Suzanne J. Hand; Michael Archer (2016). "Comparative cranial morphology in living and extinct platypuses: Feeding behavior, electroreception, and loss of teeth". Science Advances. 2 (10): e1601329. doi:10.1126/sciadv.1601329. The extinct Obdurodon was electroreceptive, but unlike the modern platypus it foraged pelagically (near the ocean surface).


In recent studies it has been suggested that the eyes of the platypus are more similar to those of Pacific hagfish or Northern Hemisphere lampreys than to those of most tetrapods. The eyes also contain double cones, which most mammals do not have.JOURNAL, Zeiss, Caroline, Comparative retinal morphology of the platypus, 10.1002/jmor.10959, 2011, Ivan R., Murphy, Christopher J., Dubielzig, Richard W., Journal of Morphology, 272, 8, 949–57, 21567446, Schwab, Although the platypus's eyes are small and not used under water, several features indicate that vision played an important role in its ancestors. The corneal surface and the adjacent surface of the lens is flat while the posterior surface of the lens is steeply curved, similar to the eyes of other aquatic mammals such as otters and sea-lions. A temporal (ear side) concentration of retinal ganglion cells, important for binocular vision, indicates a role in predation, while the accompanying visual acuity is insufficient for such activities. Furthermore, this limited acuity is matched by a low cortical magnification, a small lateral geniculate nucleus and a large optic tectum, suggesting that the visual midbrain plays a more important role than the visual cortex, as in some rodents. These features suggest that the platypus has adapted to an aquatic and nocturnal lifestyle, developing its electrosensory system at the cost of its visual system; an evolutionary process paralleled by the small number of electroreceptors in the short-beaked echidna, which dwells in dry environments, whilst the long-beaked echidna, which lives in moist environments, is intermediate between the other two monotremes.

Ecology and behaviour

(File:Animaldentition ornithoryncusanatinus.png|thumb|left|Dentition, as illustrated in Knight's Sketches in Natural History)(File:Platipus-on-the-surface.jpg|thumb|The platypus is very difficult to spot even on the surface of a river.)(File:Platypus.jpg|thumb|Platypus swimming)File:Ornithorhynchus anatinus -Sydney Aquarium, Sydney, Australia -swimming-6a.ogv|thumbtime=50|right|thumb|Swimming underwater at Sydney AquariumSydney AquariumThe platypus is semiaquatic, inhabiting small streams and rivers over an extensive range from the cold highlands of Tasmania and the Australian Alps to the tropical rainforests of coastal Queensland as far north as the base of the Cape York Peninsula.WEB,weblink Platypus, Department of Primary Industries and Water, Tasmania, 31 August 2006, 12 October 2006, yes,weblink" title="">weblink 9 October 2006, Inland, its distribution is not well known; it is extinct in South Australia (apart from an introduced population on Kangaroo Island)WEB,weblinkweblink" title="">weblink yes, 6 July 2004, Research on Kangaroo Island, University of Adelaide, 4 July 2006, 23 October 2006, and is no longer found in the main part of the Murray-Darling Basin, possibly due to the declining water quality brought about by extensive land clearing and irrigation schemes.WEB,weblink
Ornithorhynchus anatinus) and the water rat (Hydromus chrysogaster)>author1=Scott, Anthony publisher=CSIRO Australia accessdate = 23 October 2006, Along the coastal river systems, its distribution is unpredictable; it appears to be absent from some relatively healthy rivers, and yet maintains a presence in others, for example, the lower Maribyrnong River, that are quite degraded.HTTP://WWW.PLATYPUS.ASN.AU/PLATYPUS_IN_COUNTRY_AREAS.HTML ARCHIVE-DATE=17 SEPTEMBER 2016 PUBLISHER=AUSTRALIAN PLATYPUS CONSERVANCY DEADURL=YES, In captivity, platypuses have survived to 17 years of age, and wild specimens have been recaptured when 11 years old. Mortality rates for adults in the wild appear to be low. Natural predators include snakes, water rats, goannas, hawks, owls, and eagles. Low platypus numbers in northern Australia are possibly due to predation by crocodiles.WEB,weblink Platypus, Environmental Protection Agency/Queensland Parks and Wildlife Service, 2006, 24 July 2009, yes,weblink" title="">weblink 21 October 2009, The introduction of red foxes in 1845 for hunting may have had some impact on its numbers on the mainland. The platypus is generally regarded as nocturnal and crepuscular, but individuals are also active during the day, particularly when the sky is overcast.WEB,weblink Monotreme Reproductive Biology and Behavior, Iowa State University, Cromer, Erica, 14 April 2004, 18 June 2009, yes,weblink" title="">weblink 13 March 2009, JOURNAL, Philosophical Transactions: Biological Sciences, Field biology of the platypus (Ornithorhynchus anatinus): historical and current perspectives, 353, 1372, Grant, T.G., Temple-Smith, P.D., 1998, 9720106, 1081–91, 1692311, 10.1098/rstb.1998.0267, Its habitat bridges rivers and the riparian zone for both a food supply of prey species, and banks where it can dig resting and nesting burrows. It may have a range of up to {{convert|7|km|mi|abbr=on}}, with a male's home range overlapping those of three or four females.JOURNAL, Australian Journal of Zoology, Spatial-Organization and Movement Patterns of Adult Male Platypus, Ornithorhynchus-Anatinus (Monotremata, Ornithorhynchidae)issue=1author2=Serena, M. pages=91–103, 10.1071/ZO9950091, The platypus is an excellent swimmer and spends much of its time in the water foraging for food. When swimming, it can be distinguished from other Australian mammals by the absence of visible ears.WEB,weblink Platypus, Parks and Wildlife Service Tasmania, February 2008, 18 June 2009, PDF, Uniquely among mammals, it propels itself when swimming by an alternate rowing motion of the front feet; although all four feet of the platypus are webbed, the hind feet (which are held against the body) do not assist in propulsion, but are used for steering in combination with the tail.JOURNAL, The Journal of Experimental Biology, 200, 20, 2647–52, Energetics of Swimming by the Platypus Ornithorhynchus Anatinus: Metabolic Effort Associated with Rowing, Fish, F.E., Baudinette, R.V., Frappell, P.B., Sarre, M.P., 1997,weblink 9359371, The species is endothermic, maintaining its body temperature at about 32 Â°C (90 Â°F), lower than most mammals, even while foraging for hours in water below 5 Â°C (41 Â°F).Dives normally last around 30 seconds, but can last longer, although few exceed the estimated aerobic limit of 40 seconds. Recovery at the surface between dives commonly takes from 10 to 20 seconds.WEB,weblink Energetics and foraging behaviour of the platypus, University of Tasmania, Philip Bethge, April 2002, 21 June 2009, PDF, JOURNAL, The Journal of Applied Ecology, 2404239, The Diving Behaviour of the Platypus (Ornithorhynchus anatinus) in Waters with Different Trophic Status, Kruuk, H., 30, 4, 1993, 592–8, 10.2307/2404239, When not in the water, the platypus retires to a short, straight resting burrow of oval cross-section, nearly always in the riverbank not far above water level, and often hidden under a protective tangle of roots.The average sleep time of a platypus is said to be as long as 14 hours per day, possibly because it eats crustaceans, which provide a high level of calories.JOURNAL, Holland, Jennifer S., 40 Winks?, National Geographic, 220, 1, July 2011,


The platypus is a carnivore: it feeds on annelid worms, insect larvae, freshwater shrimp, and freshwater yabby (crayfish) that it digs out of the riverbed with its snout or catches while swimming. It uses cheek-pouches to carry prey to the surface, where it is eaten. The platypus needs to eat about 20% of its own weight each day, which requires it to spend an average of 12 hours daily looking for food.


(File:Ornithorhynchus anatinus - nest with eggs - MUSE.JPG|thumb|Platypus' nest with eggs replica)When the platypus was first encountered by European naturalists, they were divided over whether the female laid eggs. This was not confirmed until 1884, when William Hay Caldwell was sent to Australia, where, after extensive searching assisted by a team of 150 Aborigines, he managed to discover a few eggs. Mindful of the high cost per word, Caldwell tersely wired London, "Monotremes oviparous, ovum meroblastic." That is, monotremes lay eggs, and the eggs are similar to those of reptiles in that only part of the egg divides as it develops. The species exhibits a single breeding season; mating occurs between June and October, with some local variation taking place between different populations across its range. Historical observation, mark-and-recapture studies, and preliminary investigations of population genetics indicate the possibility of both resident and transient members of populations, and suggest a polygynous mating system.JOURNAL, Australian Journal of Zoology, Aspects of Lactation in the Platypus, Ornithorhynchus anatinus (Monotremata), in Waters of Eastern New South Wales, Grant, T. R., Griffiths, M., Leckie, R.M.C., 31, 6, 881–9, 10.1071/ZO9830881, 1983, Females are thought likely to become sexually mature in their second year, with breeding confirmed still to take place in animals over nine years old.Outside the mating season, the platypus lives in a simple ground burrow, the entrance of which is about {{convert|30|cm|in|abbr=on}} above the water level. After mating, the female constructs a deeper, more elaborate burrow up to {{convert|20|m|ft|abbr=on}} long and blocked at intervals with plugs (which may act as a safeguard against rising waters or predators, or as a method of regulating humidity and temperature).WEB,weblink Family Ornithorhynchidae (platypus), Anna Bess Sorin, Phil Myers, yes, University of Michigan Museum of Zoology, 2001, 24 October 2006, The male takes no part in caring for its young, and retreats to his year-long burrow. The female softens the ground in the burrow with dead, folded, wet leaves, and she fills the nest at the end of the tunnel with fallen leaves and reeds for bedding material. This material is dragged to the nest by tucking it underneath her curled tail.The female platypus has a pair of ovaries, but only the left one is functional. The platypus's genes are a possible evolutionary link between the mammalian XY and bird/reptile ZW sex-determination systems because one of the platypus's five X chromosomes contains the DMRT1 gene, which birds possess on their Z chromosome.JOURNAL, Jennifer, Graves, Sex Chromosome Specialization and Degeneration in Mammals, Cell, 124, 5, 901–914, 10 March 2006, 16530039, 10.1016/j.cell.2006.02.024, It lays one to three (usually two) small, leathery eggs (similar to those of reptiles), about {{convert|11|mm|in|abbr=on}} in diameter and slightly rounder than bird eggs.JOURNAL, Philosophical Transactions of the Royal Society B: Biological Sciences, Early development and embryology of the platypus, Hughes, R. L., Hall, L. S., 353, 1372, 1101–14, 28 July 1998, 9720108, 1692305, 10.1098/rstb.1998.0269, The eggs develop in utero for about 28 days, with only about 10 days of external incubation (in contrast to a chicken egg, which spends about one day in tract and 21 days externally). After laying her eggs, the female curls around them. The incubation period is divided into three phases. In the first phase, the embryo has no functional organs and relies on the yolk sac for sustenance. The yolk is absorbed by the developing young.WEB, Ockhams Razor, The Puzzling Platypus,weblink 2 December 2006, 2001-07-20, During the second phase, the digits develop, and in the last phase, the egg tooth appears.JOURNAL, Philosophical Transactions: Biological Sciences, The development of the external features of the platypus (Ornithorhynchus anatinus), Manger, Paul R., Hall, Leslie S., Pettigrew, John D., 353, 1372, 1115–25, 29 July 1998, 9720109, 1692310, 10.1098/rstb.1998.0270, Most mammal zygotes go through holoblastic cleavage, meaning that following fertilization the ovum is split due to cell divisions into multiple, divisible daughter cells. This is in comparison to the more ancestral process of meroblastic division in non-mammals (including platypuses), which causes the ovum to split but not completely. This causes the cells at the edge of the yolk to be cytoplasmically continuous with the egg’s cytoplasm. This allows the yolk, which contains the embryo, to exchange waste and nutrients with the cytoplasm.JOURNAL, Myers, P. Z.,weblink Interpreting Shared Characteristics: The Platypus Genome, Nature Education, 1, 1, 462008, 2008, The newly hatched young are vulnerable, blind, and hairless, and are fed by the mother's milk. Although possessing mammary glands, the platypus lacks teats. Instead, milk is released through pores in the skin. The milk pools in grooves on her abdomen, allowing the young to lap it up. After they hatch, the offspring are suckled for three to four months. During incubation and weaning, the mother initially leaves the burrow only for short periods, to forage. When doing so, she creates a number of thin soil plugs along the length of the burrow, possibly to protect the young from predators; pushing past these on her return forces water from her fur and allows the burrow to remain dry.WEB,weblink Egg-laying mammals, Queensland Museum, November 2000, 19 June 2009,weblink" title="">weblink 22 July 2008, yes, After about five weeks, the mother begins to spend more time away from her young and, at around four months, the young emerge from the burrow. A platypus is born with teeth, but these drop out at a very early age, leaving the horny plates it uses to grind food.BOOK, Ross Piper, Ross, Piper, Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press (publisher), Greenwood Press, 2007, 978-0-313-33922-6,


(File:Steropodon BW.jpg|thumb|left|Reconstruction of ancient platypus relative Steropodon)The platypus and other monotremes were very poorly understood, and some of the 19th century myths that grew up around them—for example, that the monotremes were "inferior" or quasireptilian—still endure.JOURNAL, Philosophical Transactions: Biological Sciences, The platypus is not a rodent: DNA hybridization, amniote phylogeny and the palimpsest theory, Kirsch, John A. W., Mayer, Gregory C., 353, 1372, 1221–37, 29 July 1998, 9720117, 1692306, 10.1098/rstb.1998.0278, In 1947, William King Gregory theorised that placental mammals and marsupials may have diverged earlier, and a subsequent branching divided the monotremes and marsupials, but later research and fossil discoveries have suggested this is incorrect.JOURNAL, Nature, 416, 6877, 165–8, 2002, 10.1038/416165a, The first Jurassic mammal from South America, Rauhut, O.W.M., Martin, T., Ortiz-Jaureguizar, E., Puerta, P., 11894091, 2002Natur.416..165R, In fact, modern monotremes are the survivors of an early branching of the mammal tree, and a later branching is thought to have led to the marsupial and placental groups.JOURNAL, Journal of Mammalian Evolution, Evolution of the Monotremes: Phylogenetic Relationship to Marsupials and Eutherians, and Estimation of Divergence Dates Based on α-Lactalbumin Amino Acid Sequences, Messer, M., Weiss, A.S., Shaw, D.C., Westerman, M., 5, 1, 95–105, March 1998, 10.1023/A:1020523120739, Molecular clock and fossil dating suggest platypuses split from echidnas around 19–48 million years ago.JOURNAL, Phillips MJ, Bennett TH, Lee MS, 2009, Molecules, morphology, and ecology indicate a recent, amphibious ancestry for echidnas, Proc. Natl. Acad. Sci. U.S.A., 106, 40, 17089–94, 10.1073/pnas.0904649106, 19805098, 2761324, 2009PNAS..10617089P, {{cladogram
|label2= live birth 
|label2= true placenta 
}}}}The oldest discovered fossil of the modern platypus dates back to about 100,000 years ago, during the Quaternary period. The extinct monotremes Teinolophos and Steropodon were once thought to be closely related to the modern platypus, but are now considered more basal taxa.Thomas H. Rich, James A. Hopson, Pamela G. Gill, Peter Trusler, Sally Rogers-Davidson, Steve Morton, Richard L. Cifelli, David Pickering, Lesley Kool, Karen Siu, Flame A. Burgmann, Tim Senden, Alistair R. Evans, Barbara E. Wagstaff, Doris Seegets-Villiers, Ian J. Corfe, Timothy F. Flannery, Ken Walker, Anne M. Musser, Michael Archer, Rebecca Pian and Patricia Vickers-Rich (2016). "The mandible and dentition of the Early Cretaceous monotreme Teinolophos trusleri". Alcheringa: An Australasian Journal of Palaeontology. in press. doi:10.1080/03115518.2016.1180034. The fossilised Steropodon was discovered in New South Wales and is composed of an opalised lower jawbone with three molar teeth (whereas the adult contemporary platypus is toothless). The molar teeth were initially thought to be tribosphenic, which would have supported a variation of Gregory's theory, but later research has suggested, while they have three cusps, they evolved under a separate process.JOURNAL, Acta Palaeontologica Polonica,weblink New data on the Paleocene monotreme Monotrematum sudamericanum, and the convergent evolution of triangulate molars, Pascual, R., Goin, F.J., Balarino, L., Udrizar Sauthier, D.E., 47, 3, 487–492, 2002, The fossil is thought to be about 110 million years old, making it the oldest mammal fossil found in Australia. Unlike the modern platypus (and echidnas), Teinolophos lacked a beak.Monotrematum sudamericanum, another fossil relative of the platypus, has been found in Argentina, indicating monotremes were present in the supercontinent of Gondwana when the continents of South America and Australia were joined via Antarctica (up to about 167 million years ago).JOURNAL, A platypus in Patagonia (Ancient life – 1992), Folger, Tim, 1993, Discover, 14, 1, 66, A fossilized tooth of a giant platypus species, Obdurodon tharalkooschild, was dated 5–15 million years ago. Judging by the tooth, the animal measured 1.3 meters long, making it the largest platypus on record.WEB,weblink 'Platypus-zilla' fossil unearthed in Australia, ZME Science, Mihai, Andrei, 2013, (File:Platypus skeleton Pengo.jpg|left|thumb|Platypus skeleton)Because of the early divergence from the therian mammals and the low numbers of extant monotreme species, the platypus is a frequent subject of research in evolutionary biology. In 2004, researchers at the Australian National University discovered the platypus has ten sex chromosomes, compared with two (XY) in most other mammals. These ten chromosomes form five unique pairs of XY in males and XX in females, i.e. males are X{{sub|1}}Y{{sub|1}}X{{sub|2}}Y{{sub|2}}X{{sub|3}}Y{{sub|3}}X{{sub|4}}Y{{sub|4}}X{{sub|5}}Y{{sub|5}}.WEB,weblink Sex, Ys, and Platypuses, Discover, Jocelyn, Selim, 25 April 2005, 7 May 2008, One of the X chromosomes of the platypus have been found to have great homology to the bird Z chromosome.JOURNAL
, Frank Grützner, Willem Rens, Enkhjargal Tsend-Ayush, Nisrine El-Mogharbel1, Patricia C. M. O'Brien, Russell C. Jones, Malcolm A. Ferguson-Smith & Jennifer A. Marshall Graves
, In the platypus a meiotic chain of ten sex chromosomes shares genes with the bird Z and mammal X chromosomes
, Nature
, 432
, 7019, 913–7
, 16 December 2004
, 10.1038/nature03021, 15502814
, 2004Natur.432..913G
The platypus genome also has both reptilian and mammalian genes associated with egg fertilisation.JOURNAL, Nature, 453, 7192, 175–183, Genome analysis of the platypus reveals unique signatures of evolution, 8 May 2008, 10.1038/nature06936, Warren, Wesley C., 18464734, 2803040, Nature Podcast 08-05-2008,weblink etal, 2008Natur.453..175W, JOURNAL, Beyond the Platypus Genome – 2008 Boden Research Conference, Reprod Fertil Dev, 21, 8, i–ix, 935–1027, 2009,weblink Though the platypus lacks the mammalian sex-determining gene SRY, a study found that the mechanism of sex determination is the AMH gene on the oldest Y chromosome.JOURNAL, Cortez, Diego; Marin, Ray; Toledo-Flores, Deborah; Froidevaux, Laure; Liechti, Angélica; Waters, Paul D.; Grützner, Frank; Kaessmann, Henrik, 2014, Origins and functional evolution of Y chromosomes across mammals, Nature, 508, 7497, 488–493, 10.1038/nature13151, 24759410, 2014Natur.508..488C, NEWS, Salleh, Anna, Platypus Sex 'Master Switch' Identified,weblink Australian Broadcasting Corporation, 5 May 2014, A draft version of the platypus genome sequence was published in Nature on 8 May 2008, revealing both reptilian and mammalian elements, as well as two genes found previously only in birds, amphibians, and fish. More than 80% of the platypus's genes are common to the other mammals whose genomes have been sequenced.


(File:platypus-plate.jpg|thumb|upright|A depiction of a platypus from a book for children published in Germany in 1798)Except for its loss from the state of South Australia, the platypus occupies the same general distribution as it did prior to European settlement of Australia. However, local changes and fragmentation of distribution due to human modification of its habitat are documented. Its current and historical abundance, however, are less well-known and it has probably declined in numbers, although still being considered as common over most of its current range. The species was extensively hunted for its fur until the early years of the 20th century and, although protected throughout Australia since 1905, until about 1950 it was still at risk of drowning in the nets of inland fisheries. The platypus does not appear to be in immediate danger of extinction, because conservation measures have been successful, but it could be affected by habitat disruption caused by dams, irrigation, pollution, netting, and trapping. Reduction of watercourse flows and water levels through excessive droughts and extraction of water for industrial, agricultural, and domestic supplies are also considered a threat. The IUCN lists the platypus on its Red List as "Near Threatened".Platypuses generally suffer from few diseases in the wild; however, public concern in Tasmania is widespread about the potential impacts of a disease caused by the fungus Mucor amphibiorum. The disease (termed mucormycosis) affects only Tasmanian platypuses, and has not been observed in platypuses in mainland Australia. Affected platypuses can develop skin lesions or ulcers on various parts of their bodies, including their backs, tails, and legs. Mucormycosis can kill platypuses, death arising from secondary infection and by affecting the animals' ability to maintain body temperature and forage efficiently. The Biodiversity Conservation Branch at the Department of Primary Industries and Water are collaborating with NRM north and University of Tasmania researchers to determine the impacts of the disease on Tasmanian platypuses, as well as the mechanism of transmission and current spread of the disease.WEB,weblink Platypus Fungal Disease, Department of Primary Industries and Water, Tasmania, 29 August 2008, 29 February 2008, yes,weblink" title="">weblink 7 March 2008, Much of the world was introduced to the platypus in 1939 when National Geographic Magazine published an article on the platypus and the efforts to study and raise it in captivity. The latter is a difficult task, and only a few young have been successfully raised since, notably at Healesville Sanctuary in Victoria. The leading figure in these efforts was David Fleay, who established a platypusary—a simulated stream in a tank—at the Healesville Sanctuary, where breeding was successful in 1943.WEB,weblink Fantastic Fleay turns 20!, 4 February 2014, 31 October 2013, Zoos Victoria,
In 1972, he found a dead baby of about 50 days old, which had presumably been born in captivity, at his wildlife park at Burleigh Heads on the Gold Coast, Queensland.WEB,weblink David Fleay's achievements, Queensland Government, 23 November 2003, 13 September 2006,weblink" title="">weblink 2 October 2006, yes, Healesville repeated its success in 1998 and again in 2000 with a similar stream tank. Since 2008, platypus has bred regularly at Healesville,WEB,weblink Pitter patter - Platypus twins!, Zoo Victoria, 4 March 2013, 17 August 2017, including second-generation (captive born themselves breeding in captivity).WEB,weblink Zoos, Australian Platypus Conservancy, 17 August 2017, 2016-11-22, Taronga Zoo in Sydney bred twins in 2003, and breeding was again successful there in 2006.WEB,weblink Platypus, Catalyst, 13 November 2003, 13 September 2006,

Platypus in wildlife sanctuaries

The platypus is kept, for conservation purposes, in special aquariums at the following Australian wildlife sanctuaries:


File:Platypus house at Lone Pine Koala Sanctuary.jpg|thumb|Platypus House at Lone Pine Koala SanctuaryLone Pine Koala Sanctuary

New South Wales


  • Healesville Sanctuary, near Melbourne, Victoria, where the platypus was first bred in captivity by naturalist David Fleay in 1943. The first platypus "born" in captivity was named "Corrie" and was quite popular with the public. In 1955, three months before a new "platypussary" (after "aviary") was opened, she unfortunately escaped from her pen into the nearby Badger Creek and apparently was never recovered.


{{as of|2017}}, there is no platypus in captivity outside of Australia. Three attempts were made to bring the animals to the Bronx Zoo, in 1922, 1947, and 1958; of these, only two of the three animals introduced in 1947 lived longer than eighteen months.BOOK, Lee S. Crandall, The Management of Wild Mammals in Captivity, University of Chicago Press, 1964,

Cultural references

(File:Latrobe BigPlatypus.jpg|thumb|right|Big Platypus at the Australian Axeman's Hall of Fame)The platypus has been a subject in the Dreamtime stories of indigenous Australians, who believed the animal was a hybrid of a duck and a water rat.BOOK, McKay, Helen F., McLeod, Pauline E., Jones, Francis F., Barber, June E., 2001, Gadi Mirrabooka: Australian Aboriginal Tales from the Dreaming, Libraries Unlimited, 978-1563089237, {{rp|57–60}} According to one story, the major animal groups, the land animals, water animals and birds, all competed for the platypus to join their respective groups, but the platypus ultimately decided to not join any of them, feeling that he did not need to be part of a group to be special.{{rp|83–85}}(File:Platypus cape unknown tasmania.jpg|thumb|A platypus fur cape. Made in 1890. Donated to the National Gallery of Victoria by Mrs F Smith in 1985)Platypuses has been used several times as a mascot: "Syd" the platypus was one of the three mascots chosen for the Sydney 2000 Olympics along with an echidna and a kookaburra,WEB,weblink A Brief History of the Olympic and Paralympic Mascots, Beijing2008, 5 August 2004, 25 October 2006, yes,weblink" title="">weblink 21 June 2008, "Expo Oz" the platypus was the mascot for World Expo 88, which was held in Brisbane in 1988,WEB,weblink About World Expo '88, Foundation Expo '88, 1988, 17 December 2007, yes,weblink" title="">weblink 19 December 2013, and Hexley the platypus is the mascot for the Darwin operating system, the BSD-based core of macOS and other operating systems from Apple Inc.WEB,weblink The Home of Hexley the Platypus, 25 October 2006, The platypus has been featured in songs, such as Green Day's "Platypus (I Hate You)" and Mr. Bungle's "Platypus". It is the subject of a children's poem by Banjo Paterson.{{multiple image
| width1 = 140
| image1 = Australianstamp 1551.jpg
| caption1 = 9d postage stamp from 1937
| width2 = 120
| image2 =
| caption2 = 20-cent coin in use since 1966
}}The platypus has frequently appeared in Australian postage stamps and coins. The earliest appearance is the 9d Australian stamp from 1937. The platypus re-appeared in the 1960–64 Australian Native Animal Series. Souvenir sheet of "from" Laos and Equatorial Guinea has also featured the animal. The platypus has appeared on a 1987 36 cent stamp and an Australian 1996 95 cent stamp. The 2006 Australian Bush Babies stamp series features a $4.65AUD stamp of a young platypus. A 5 cent stamp also produced in 2006 features the platypus also. Since the introduction of decimal currency to Australia in 1966, the embossed image of a platypus, designed and sculpted by Stuart Devlin, has appeared on the reverse (tails) side of the 20-cent coin.In the animated series Phineas and Ferb, the title characters own a pet platypus, named Perry, who unknown to them, is a secret agent. The choice of a platypus was inspired by media underuse, as well as to exploit the animal's striking appearance.NEWS,weblink Disney gives 'Ferb' pickup, major push – Q&A: Dan Povenmire, 2009-06-07, Hollywood Reporter, 2017-03-05, As a character, Perry has been well received by both fans and critics.WEB,weblink 'Phineas' star Perry makes mark on auds, Littleton, Cynthia, 2009-11-20, Variety (magazine), Variety, 2009-11-26, JOURNAL,weblink Five Reasons Why Phineas and Ferb is the Best Kids Show on TV, Paste (magazine), Paste, Jackson, John, 2009-03-31, 2009-11-25,

See also





  • ENCYCLOPEDIA, Augee, Michael L., World Book Encyclopedia, Platypus, 2001,
  • BOOK, Burrell, Harry, The Platypus, Rigby, Adelaide SA, 1974, 978-0-85179-521-8,
  • BOOK, Fleay, David H., Paradoxical Platypus: Hobnobbing with Duckbills, Jacaranda Press, 1980, 978-0-7016-1364-8,weblink
  • BOOK, Grant, Tom, The platypus: a unique mammal, University of New South Wales Press, Sydney, 1995, 978-0-86840-143-0,weblink
  • BOOK, Griffiths, Mervyn, The Biology of the Monotremes, Academic Press, 1978, 978-0-12-303850-0,weblink
  • ENCYCLOPEDIA, Hutch, Michael, McDade, Melissa C., Grzimek's Animal Life Encyclopedia, 2004, Gale, 12,
  • BOOK, Moyal, Ann Mozley, Ann Moyal, Platypus: The Extraordinary Story of How a Curious Creature Baffled the World, The Johns Hopkins University Press, Baltimore, 2004, 978-0-8018-8052-0,weblink
  • BOOK, Ronald, Strahan, Steve, Van Dyck, Mammals of Australia, 3rd,weblink April 2006, New Holland, 978-1-877069-25-3,


External links

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