Platypus

From Wikipedia, the free encyclopedia

For other uses, see Platypus (disambiguation).

iPlatypus
Conservation status
Image:Status iucn2.3 LC.svg Least concern (LR/lc)<ref name="IUCN">Australasian Marsupial & Monotreme Specialist Group (1996). Ornithorhynchus anatinus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 09 May 2006. Database entry includes a brief justification of why this species is of least concern </ref> </div>
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Monotremata Family: Ornithorhynchidae Genus: Ornithorhynchus Blumenbach, 1800 Species: O. anatinus
Binomial name
Ornithorhynchus anatinus (Shaw, 1799)
Image:Platypus Distribution.png Platypus range (indicated by darker shading)<ref name="APC">Platypus facts file. Australian Platypus Conservancy. Retrieved on 13 September, 2006.</ref>

The platypus (Ornithorhynchus anatinus) is a semi-aquatic mammal endemic to eastern Australia and Tasmania. Together with the four species of echidna, it is one of the five species of monotremes, the only mammals that lay eggs instead of giving birth to live young. It is the sole living representative of its family (Ornithorhynchidae) and genus (Ornithorhynchus), though a number of related species have been found in the fossil record.

The bizarre appearance of this egg-laying, duck-billed mammal baffled naturalists when it was first discovered, with some considering it an elaborate fraud. It is one of the few venomous mammals; male platypuses have a spur on the hind foot which delivers a poison capable of causing severe pain to humans. 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 is featured on the reverse of the Australian 20-cent coin.

Until the early 20th century it was hunted 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.

[edit] Taxonomy and etymology

When the platypus was first discovered by Europeans in the late 1700s, a pelt and sketch were sent back to the United Kingdom by Captain John Hunter, the second Governor of New South Wales.<ref name="Paradox">Brian K. Hall (1999-03). "The Paradoxical Platypus". BioScience 49 (3): 211-218.</ref> The British scientists were at first convinced that the odd collection of physical attributes must have been a hoax.<ref name="APC" /> George Shaw, who produced the first description of the animal in the Naturalist's Miscellany in 1799 stated that it was impossible not to entertain doubts as to its genuine nature, and Robert Knox believed it may have been produced by some Asian taxidermist.<ref name="hoax">Duck-billed Platypus. Museum of hoaxes. Retrieved on 14 September, 2006.</ref> 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.<ref name="APC" />

The common name, platypus, is Latin derived from the Greek words πλατύς ("platys", flat, broad) and πους ("pous", foot), meaning "flat foot".<ref> Liddell & Scott (1980). Greek-English Lexicon, Abridged Edition. Oxford University Press, Oxford, UK. ISBN 0-19-910207-4.</ref> Shaw assigned it as a Linnaean genus name when he initially described it, but the term was quickly discovered to already belong to the wood-boring ambrosia beetle (genus Platypus).<ref name="ABRS">J.R.Grant. Fauna of Australia chap.16 vol.1b. Australian Biological Resources Study (ABRS). Retrieved on 13 September, 2006.</ref> It was independently described as Ornithorhynchus paradoxus by Johann Blumenbach in 1800 (from a specimen given to him by Sir Joseph Banks)<ref name="NLA">Platypus Paradoxes. National Library of Australia (2001-08). Retrieved on 14 September, 2006.</ref> and following the rules of priority of nomenclature it was later officially recognised as Ornithorhynchus anatinus.<ref name="ABRS"/> The scientific name Ornithorhynchus is derived from ορνιθόρυγχος ("ornithorhynkhos"), which literally means "bird snout" in Greek, and anatinus which means "duck-like" in Latin.

There is no universally agreed upon plural of "platypus" in the English language. Scientists generally use "platypuses", "platypoda", or simply "platypus". Colloquially, "platypi" is also used for the plural, although this is pseudo-Latin.<ref name="APC" /> Early British settlers called it by many names, such as watermole, duckbill, and duckmole.<ref name="APC" /> The name platypus is often prefixed with the adjective "duck-billed" to form duck-billed platypus, despite there being only one species of platypus.

[edit] Description

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.<ref name="APC" /><ref name="ABRS" /> The platypus uses its tail for storage of fat reserves, an adaptation it shares with the Tasmanian Devil.<ref name="Guiler">Guiler, E.R. (1983). “Tasmanian Devil”, R. Strahan Ed.: The Australian Museum Complete Book of Australian Mammals. Angus & Robertson, 27-28. ISBN 0-207-14454-0.</ref> It has webbed feet and a large, rubbery snout; these are features that appear closer to those of a duck than to those of any known mammal. The webbing is more significant on the front feet and is folded back when walking on land.<ref name="ABRS" /> Unlike a bird's beak (in which both the upper and lower parts of the beak separate to reveal its mouth), the snout of the platypus is a sensory organ with the mouth on the underside. 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.<ref name="ABRS" /> Platypuses have been heard to emit a low growl when disturbed and a range of other vocalisations have been reported in captive specimens.<ref name="APC" />

Weight varies considerably from 700 g (1.54 lb) to 2.4 kg (5.3 lb) with males being larger than females: males average 50 cm (20 in) total length while females average 43 cm (17 in).<ref name="ABRS" /> There is 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.<ref name="Workshop">Sarah Munks and Stewart Nicol (1999-05). Current research on the platypus, Ornithorhynchus anatinus in Tasmania: Abstracts from the 1999 ‘Tasmanian Platypus WORKSHOP’. University of Tasmania. Retrieved on 23 October, 2006.</ref>

The platypus has an average body temperature of 31–32 °C (88–90 °F) rather than the 38 °C (100 °F) typical of placental mammals.<ref name="DC">Thermal Biology of the Platypus. Davidson College (1999). Retrieved on 14 September, 2006.</ref> 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.<ref name="temp">J.M. Watson and J.A.M. Graves (1988). "Monotreme Cell-Cycles and the Evolution of Homeothermy". Australian Journal of Zoology 36 (5): 573-584.</ref><ref name="temp2">T.J. Dawson, T.R. Grant and D. Fanning (1979). "Standard Metabolism of Monotremes and the Evolution of Homeothermy". Australian Journal of Zoology 27 (4): 511-515.</ref>

Modern platypus young have three-cusped molars which they lose before or just after leaving the breeding burrow;<ref name="MS">Pascual, R., Goin, F.J., Balarino, L., and Udrizar Sauthier, D.E. (2002). "New data on the Paleocene monotreme Monotrematum sudamericanum, and the convergent evolution of triangulate molars". Acta Palaeontologica Polonica 47 (3): 487-492.</ref><ref name="geowords">Hugh Race. Living mammals are placentals (eutheria), marsupials, and monotremes. Geowords. Retrieved on 19 September, 2006.</ref> adults have heavily keratinised pads in their place.<ref name="ABRS" /> The platypus jaw is constructed differently from that of other mammals, and the jaw opening muscle is different.<ref name="ABRS" /> 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 pre-mammalian synapsids. However, the external opening of the ear still lies at the base of the jaw.<ref name="ABRS" /> The platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammals.<ref name="ABRS" /> It has a reptilian gait, with legs that are on the sides of the body, rather than underneath.<ref name="ABRS" />

[edit] Venom

The male platypus has venomous ankle spurs which produce a cocktail of venom, composed largely of defensin-like proteins (DLPs), which is unique to the platypus.<ref name="PS">Gerritsen, Vivienne Baillie (2002-12). "Platypus poison". Protein Spotlight (29). Retrieved on 14 September.</ref> Although powerful enough to kill smaller animals,<ref name="PS" /> the venom is not lethal to humans, but does produce excruciating pain; so intense that the victim may be incapacitated. Oedema rapidly develops around the wound and gradually spreads throughout the affected limb. Information obtained from case histories and anecdotal evidence indicates that the pain develops into a long-lasting hyperalgesia that persists for days or even months.<ref name="JN">G. M. de Plater, P. J. Milburn and R. L. Martin (2001-3). "Venom From the Platypus, Ornithorhynchus anatinus, Induces a Calcium-Dependent Current in Cultured Dorsal Root Ganglion Cells". Journal of Neurophysiology 85 (3): 1340-1345.</ref><ref name="venom">The venom of the platypus (Ornithorhynchus anatinus). Retrieved on 13 September, 2006.</ref> Venom is produced in the crural glands of the male, which are kidney-shaped alveolar glands connected by a thin-walled duct to a calcaneous spur on each hind limb. Female platypuses, in common with echidnas, have rudimentary spur buds which do not develop (dropping off before the end of their first year) and lack functional crural glands.<ref name="ABRS" />

The venom appears to have a different function from those produced by non-mammalian species: its effects are non-life threatening but nevertheless powerful enough to seriously impair the victim. Since only males produce venom and production rises during the breeding season it is theorized that it is used as an offensive weapon to assert dominance during this period.<ref name="PS" />

[edit] Electrolocation

Monotremes are the only mammals known to have a sense of electroreception: they locate their prey in part by detecting electric fields generated by muscular contractions. The platypus' electroreception is the most sensitive of any monotreme.<ref name="Electro1">Pettigrew, John D. (1999). "Electroreception in Monotremes". The Journal of Experimental Biology (202): 1447–1454. Retrieved on 19 September.</ref>

The electroreceptors are located in rostro-caudal 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. 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 animal's characteristic side-to-side motion of its head while hunting. The cortical convergence of electrosensory and tactile inputs suggests a mechanism for determining the distance of prey items which, when they move, emit both electrical signals and mechanical pressure pulses, which would also allow for computation of distance from the difference in time of arrival of the two signals.<ref name="Electro1" />

The platypus feeds by digging in the bottom of streams with its bill. The electroreceptors could be used to distinguish animate and inanimate objects in this situation (in which the mechanoreceptors would be continuously stimulated).<ref name="Electro1" /> When disturbed, its prey would generate tiny electrical currents in their muscular contractions which the sensitive electroreceptors of the platypus could detect. Experiments have shown that the platypus will even react to an 'artificial shrimp' if a small electrical current is passed through it.<ref name=Manning>Manning, A & Dawkins, M.S. (1998). An Introduction to Animal Behaviour Fifth Edition. Cambridge University Press.</ref>

[edit] Ecology and behaviour

Image:Platipus-on-the-surface.jpg The platypus is semi-aquatic, 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.<ref name="DPIW">Platypus. Department of Primary Industries and Water, Tasmania (2006-08-31). Retrieved on 12 October, 2006.</ref> Inland, its distribution is not well known: it is extinct in South Australia (bar an introduced population on Kangaroo Island)<ref name="RKI">Research on Kangaroo Island. University of Adelaide (2006-07-04). Retrieved on 23 October, 2006.</ref> 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.<ref name="CSIRO">Anthony Scott and Tom Grant (1997-11). Impacts of water management in the Murray-Darling Basin on the platypus (Ornithorhynchus anatinus) and the water rat (Hydromus chrysogaster). CSIRO Australia. Retrieved on 23 October, 2006.</ref> 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 that are quite degraded (the lower Maribyrnong, for example).<ref name="APC2">Platypus in Country Areas. Australian Platypus Conservancy. Retrieved on 23 October, 2006.</ref>

In captivity platypuses have survived to seventeen years of age and wild specimens have been recaptured at eleven years old. Mortality rates for adults in the wild appear to be low.<ref name="ABRS" /> Natural predators include snakes, water rats, goannas, hawks, owls and eagles, and low platypus numbers in the northern Australia are possibly due to predation by crocodiles.<ref name="EPA">Platypus. Environmental Protection Agency/Queensland Parks and Wildlife Service (2006). Retrieved on 24 October, 2006.</ref> The introduction of red foxes as a predator for rabbits may have had some impact on its numbers on the mainland.<ref name="Workshop" /> The platypus is generally regarded as nocturnal and crepuscular, but individuals are also active during the day, particularly when the sky is overcast.<ref name="EC">Erica Cromer (2004-04-14). Monotreme Reproductive Biology and Behavior. Iowa State University. Retrieved on 23 October, 2006.</ref><ref name="HCP">T.G. Grant and P. D. Temple-Smith (1998-07-29). "Field Biology of the Platypus (Ornithorhynchus Anatinus): Historical and Current Perspectives". Philosophical Transactions: Biological Sciences 353 (1372): 1081-1091.</ref> 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.<ref name="HCP" /> It may have a range of up to 7 km (4.4 mi) with male's home ranges overlapping with those of 3 or 4 females.<ref name="AJZ4">J.L. Gardner and M. Serena (1995). "Spatial-Organization and Movement Patterns of Adult Male Platypus, Ornithorhynchus-Anatinus (Monotremata, Ornithorhynchidae)". Australian Journal of Zoology 43 (1): 91-103.</ref>

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.<ref name="parks">Platypus. Parks and Wildlife Service Tasmania (2003-12). Retrieved on 23 October, 2006.</ref> Uniquely among mammals it propels itself when swimming by alternate rowing motion with the front two 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.<ref name="Rowing">F.E. Fish, R.V. Baudinette, P.B. Frappell, and M.P. Sarre (1997-07-28). "Energetics of Swimming by the Platypus Ornithorhynchus Anatinus: Metabolic Effort Associated with Rowing". The Journal of Experimental Biology 200 (20): 2647–2652.</ref> The species is endothermic, maintaining its low body temperature, even while foraging for hours in water below 5 °C (41 °F).<ref name="ABRS" />

Dives normally last around 30 seconds, but can last longer although few exceed the estimated aerobic limit of 40 seconds. 10 to 20 seconds are commonly spent in recovery at the surface.<ref name="Bethge">Philip Bethge (2002-04). Energetics and foraging behaviour of the platypus. University of Tasmania. Retrieved on 23 October, 2006.</ref><ref>H. Kruuk (1993). "The Diving Behaviour of the Platypus (Ornithorhynchus anatinus) in Waters with Different Trophic Status". The Journal of Applied Ecology 30 (4): 592-598.</ref> The platypus is a carnivore: it feeds on annelid worms and insect larvae, freshwater shrimps, and yabbies (freshwater crayfish) that it digs out of the riverbed with its snout or catches while swimming. It utilizes cheek-pouches to carry prey to the surface where they are eaten.<ref name="parks" /> The platypus needs to eat about 20% of its own weight each day. This requires the platypus to spend an average of 12 hours each day looking for food.<ref name="Bethge" /> 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.<ref name="parks" />

[edit] Reproduction

When the platypus was first discovered scientists were divided over whether the female laid eggs. This was not confirmed until 1884 when W.H. Caldwell was sent to Australia where, after extensive searching assisted by a team of 150 aborigines, he managed to discover a few eggs.<ref name="ABRS"/><ref name="PS"/> Mindful of the high cost of wiring England based on the cost per word, Caldwell famously but tersely wired London,"Monotremes oviparous, ovum meroblastic." That is, monotremes lay eggs. The yolk is absorbed by the developing young.<ref>Ockhams Razor. The Puzzling Platypus. Retrieved on 2006-12-02.</ref>

The species exhibits a single breeding season, with mating occurring between June and October, with some local variation taking place in populations across the extent of its range.<ref name="EPA" /> Historical observation, mark and recapture studies and preliminary investigations of population genetics indicate the possibility of resident and transient members of populations and suggest a polygynous mating system.<ref name="AJZ2">T.R. Grant, M. Griffiths and R.M.C. Leckie. "Aspects of Lactation in the Platypus, Ornithorhynchus anatinus (Monotremata), in Waters of Eastern New South Wales". Australian Journal of Zoology 31 (6): 881-889.</ref> Females are thought likely to become sexually mature in their second year, with breeding confirmed to still take place in animals over nine years old.<ref name="AJZ2"/>

Outside the mating season, the platypus lives in a simple ground burrow whose entrance is about 30 cm (1 ft) above the water level. After mating, the female constructs a deeper, more elaborate burrow up to 20 m (66 ft) long and blocked with plugs at intervals (which may act as a safeguard against rising waters or predators, or as a method of regulating humidity and temperature).<ref name="ADW">Anna Bess Sorin and Phil Myers (2001). Family Ornithorhynchidae (platypus). University of Michigan Museum of Zoology. Retrieved on 24 October, 2006.</ref> The male takes no part in caring for its young, and retreats to its yearlong 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.<ref name="APC" />

The female platypus has a pair of ovaries but only the left one is functional.<ref name="EC" /> It lays one to three (usually two) small, leathery eggs (similar to those of reptiles), that are about 11 mm (7/16 in) in diameter and slightly rounder than bird eggs.<ref name="BSED">R. L. Hughes and L. S. Hall (1998-07-29). "Early development and embryology of the platypus". Philosophical Transactions of the Royal Society B: Biological Sciences 353 (1372): 1101-1114.</ref> 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 1 day in tract and 28 days externally).<ref name="EC" /> After laying her eggs, the female curls around them. The incubation period is separated into three parts. In the first, the embryo has no functional organs and relies on the yolk sac for sustenance. During the second, the digits develop, and in the last, the egg tooth appears.<ref name="RS2">Paul R. Manger, Leslie S. Hall, John D. Pettigrew (1998-07-29). "The Development of the External Features of the Platypus (Ornithorhynchus Anatinus)". Philosophical Transactions: Biological Sciences 353 (1372): 1115-1125.</ref>

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. There are grooves on her abdomen that form pools of milk, allowing the young to lap it up.<ref name="APC" /><ref name="EPA" /> After they hatch, the offspring are suckled for three to four months. During incubation and weaning, the mother initially only leaves the burrow for short periods to forage. When doing so, she creates a number of thin soil plugs along the length of 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.<ref name="QM">Egg-laying mammals. Queensland Museum (2000-11). Retrieved on 24 October, 2006.</ref> 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.<ref name="EPA" />

[edit] In mammalian evolution

The platypus and other monotremes were very poorly understood for many years and some of the 19th century myths that grew up around them, for example, that the monotremes were "inferior" or quasi-reptilian, still endure.<ref name="Rodent">John A. W. Kirsch and Gregory C. Mayer (1998-07-29). "The Platypus is not a Rodent: DNA Hybridization, Amniote Phylogeny and the Palimpsest Theory". Philosophical Transactions: Biological Sciences 353 (1372): 1221-1237.</ref> It is now generally accepted that modern monotremes are the survivors of an early branching of the mammal tree; a later branching is thought to have led to the marsupial and placental groups.<ref name="JME">M. Messer, A.S. Weiss, D.C. Shaw and M. Westerman (1998-03). "Evolution of the Monotremes: Phylogenetic Relationship to Marsupials and Eutherians, and Estimation of Divergence Dates Based on α-Lactalbumin Amino Acid Sequences". Journal of Mammalian Evolution 5 (1): 95-105.</ref><ref name="Rodent" /> Although in 1947, William King Gregory had theorized that placental mammals and marsupials may have diverged earlier with a subsequent branching dividing the monotremes and marsupials, later research and fossil discoveries have suggested this is incorrect.<ref name="Rodent" /><ref name="JM">O. W. M. Rauhut, T. Martin, E. Ortiz-Jaureguizar and P. Puerta (2001-12-11). The first Jurassic mammal from South America. Nature. Retrieved on 24 October, 2006.</ref> Due to the unique combination of its features the platypus is also a topic in arguments over Darwinian evolution and intelligent design, with both sides claiming that its existence gives weight to their theory.<ref name="DI1">Jonathan Witt (2004-08-01). The Gods Must Be Tidy! Is the Cosmos a Work of Poor Engineering or the Gift of an Artistic Designer?. Touchstone Magazine. The Discovery Institute. Retrieved on 24 October, 2006.</ref><ref name="DI2">Josh Gilder (2001-09-24). PBS’s ‘Evolution’ series is propaganda, not science. World Net Daily. The Discovery Institute. Retrieved on 24 October, 2006.</ref>

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 closely related to the modern platypus.<ref name="JM" /> 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.<ref name="MS" /> The fossil is thought to be about 110 million years old, which means that the platypus-like animal was alive during the Cretaceous period, making it the oldest mammal fossil found in Australia. Monotrematum sudamericanum, another fossil relative of the platypus has been found in Argentina, indicating that 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).<ref name="MS" /><ref name="patagonia">Tim Folger (1993-01). A platypus in Patagonia — Ancient life. Discover. Retrieved on 17 October, 2006.</ref>

Because of the early divergence from the therian mammals and the low numbers of extant monotreme species, it 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 to two (XY) found in most other mammals (for instance, a male platypus is always XYXYXYXYXY). Furthermore, one of the platypus’s Y chromosomes shares genes with the ZZ/ZW sex chromosomes found in birds. This news further pronounced the individuality of the platypus in the animal kingdom.<ref name="discover">Jocelyn Selim (2005-04-25). Sex, Ys, and Platypuses. Discover. Retrieved on 13 September, 2006.</ref>

[edit] Conservation status

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, is less well known and it has probably declined in numbers, although still being considered as common over most of its current range.<ref name="HCP" /> The species was extensively hunted for its fur until the early years of the 20th century and, although protected throughout Australia in 1905,<ref name="QM" /> up until about 1950 it was still at risk of drowning in the nets of inland fisheries.<ref name="CSIRO" /> The platypus does not appear to be in immediate danger of extinction thanks to conservation measures, but it could be impacted by habitat disruption caused by dams, irrigation, pollution, netting and trapping.<ref name="IUCN" /> The IUCN lists the platypus on its Red List as Least Concern.<ref name="IUCN" />

A fungal infection poses a possible threat to platypuses in Tasmania. The fungus, Mucor amphiborum causes ulceration on the body that can lead to problems with thermoregulation and death from secondary infections. The same fungus so far causes no problems to the platypus on the Australian mainland. The Tasmania Parks and Wildlife Service and Biodiversity Conservation Branch Department of Primary Industries and Water are collaborating to monitor the effects of the infection on the platypus population in Tasmania.<ref name="DPIW2">Platypus Disease Threat. Department of Primary Industries and Water, Tasmania (2006-09-05). Retrieved on 12 October, 2006.</ref> Platypuses in Tasmania tend to be larger than those found in the mainland of Australia, possibly because of the lack of introduced predators. The failure to establish the red fox in particular is theorized to be a contributing factor to both the greater average size and abundance of the platypus in the state.<ref name="Workshop" />

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. This 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 platypussary — a simulated stream in a tank — at the Healesville Sanctuary and had a successful breeding in 1943. 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.<ref name="DF">David Fleay's achievements. Queenland Government (2003-11-23). Retrieved on 13 September, 2006.</ref> Healesville repeated its success in 1998 and again in 2000 with a similar stream tank. Taronga Zoo in Sydney bred twins in 2003, and had another birth in 2006.<ref name="catalyst">Platypus. Catalyst (2003-11-13). Retrieved on 13 September, 2006.</ref>

[edit] In popular culture

The platypus is sometimes jokingly referred to as proof that God has a sense of humor (at the beginning of the film Dogma for example). Its unusual appearance has led to it featuring in many media, particularly in its native Australia. The platypus 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,<ref>A Brief History of the Olympic and Paralympic Mascots. Bejing2008 (2004-08-05). Retrieved on 25 October, 2006.</ref> while Hexley the platypus is the mascot for Apple Computer's BSD-based Darwin operating system, Mac OS X.<ref>The Home of Hexley the Platypus. Retrieved on 25 October, 2006.</ref> A platypus named Phyl appears in several of the books written by Timothy Budd. Phyl is used to illustrate two important principles of object-oriented programming: inheritance and overriding.<ref>[http://web.engr.oregonstate.edu/~budd/Books/oopintro/ An Introduction to Object-Oriented Programming]. Retrieved on 26 October, 2006.</ref> The satirist Barry Humphries exhibited the box of a mock pesticide product called "Platytox" during his early surrealist period.<ref>Barry Humphries. Picture Australia. Retrieved on 25 October, 2006.</ref> Experimental rock band Mr. Bungle has a track named after the creature on their second major album, Disco Volante.<ref>Disco Volante Track Listing. Amazon. Retrieved on 25 October, 2006.</ref>

Platypuses are frequently seen in children's cartoons: a platypus named Ovide was the star of the cartoon Ovide and the Gang;<ref>Ovide and the Gang. IMDB. Retrieved on 25 October, 2006.</ref> two platypuses appear in the cartoon Taz-Mania; a young platypus named Flap is a regular character in each of the Blinky Bill cartoon series; and in the animated show Camp Lazlo, the character of Edward is a platypus. In 1995, United Paramount Network broadcast a short-lived television series entitled Platypus Man, starring comedian Richard Jeni. The title came from a joke, repeated at the beginning of each episode, comparing the platypus' solitary behavior with the lead character's personal life.

[edit] See also

• Australian fauna
• List of venomous mammals
• Henry Burrell

[edit] Notes

[edit] References

Books

Documentary

[edit] External links

• PBS.org
• Platypus at WikiFauna
• Platypus-Evolution and Conservation
• Photo of a platypus egg

   

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ar:خلد الماء bg:Птицечовка cs:Ptakopysk da:Næbdyr de:Schnabeltier et:Nokkloom es:Ornitorrinco eo:Ornitorinko fa:نوک‌اردکی fr:Ornithorynque hu:Kacsacsőrű emlős ko:오리너구리 io:Ornitorinko id:Platipus os:Бабызвындз is:Breiðnefur it:Ornithorhynchus anatinus he:ברווזן lt:Ančiasnapis ms:Platypus nl:Vogelbekdier ja:カモノハシ no:Nebbdyr pl:Dziobak pt:Ornitorrinco ru:Утконос simple:Platypus fi:Vesinokkaeläin sv:Näbbdjur th:ตุ่นปากเป็ด tr:Ornitorenk ur:ڈک بل vi:Thú mỏ vịt zh:鸭嘴兽