Platypus[1]
Conservation status
Least Concern (IUCN 2.3)[2]
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Monotremata Family: Ornithorhynchidae Genus: Ornithorhynchus Blumenbach, 1800 Species: O. The conservation status of a Species is an indicator of the likelihood of that species remaining extant either in the present day or the near future Least Concern ( LC) is an IUCN category assigned to extant species or lower taxa which have been evaluated but do not qualify for any other category The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List) created in 1963 is the world's most comprehensive inventory of the global Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Monotremes (from the Greek monos 'single' + trema 'hole' referring to the Cloaca) are Mammals that lay eggs ( Prototheria) instead Ornithorhynchidae is one of the two extant families in the order Monotremata, and contains the Platypus and its extinct relatives Johann Friedrich Blumenbach ( May 11, 1752 – January 22, 1840) was a German doctor and Physiologist, anatinus
Binomial name
Ornithorhynchus anatinus (Shaw, 1799)
Platypus range (indicated by darker shading)[3]

The Platypus (Ornithorhynchus anatinus) is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. George Shaw ( December 10, 1751 - July 22, 1813) was an English Botanist and Zoologist. An aquatic animal is an Animal which lives in water for most or all of the time Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Endemism is the Ecological state of being unique to a place Endemic species are not naturally found elsewhere The Eastern states of Australia refers to the states adjoining the east coast of Australia. Tasmania is an Australian island and state of the same name It is located south of the eastern side of the Continent, being separated from it by Bass Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young. Echidnas (ɨˈkɪdnə also known as spiny anteaters, are four extant Mammal species belonging to the Tachyglossidae family of the Monotremes (from the Greek monos 'single' + trema 'hole' referring to the Cloaca) are Mammals that lay eggs ( Prototheria) instead In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum. 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. In Biological classification, family ( Latin Ornithorhynchidae is one of the two extant families in the order Monotremata, and contains the Platypus and its extinct relatives A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic Monotremes (from the Greek monos 'single' + trema 'hole' referring to the Cloaca) are Mammals that lay eggs ( Prototheria) instead

The bizarre appearance of this egg-laying, venomous, duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, with some considering it an elaborate fraud. This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. For duck as a food see Duck (food; for other meanings see Duck (disambiguation. Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe Otters are semi- aquatic (or in one case aquatic) fish-eating Mammals The otter subfamily Lutrinae forms part of the family It is one of the few venomous mammals; the male Platypus has a spur on the hind foot that delivers a venom capable of causing severe pain to humans. Venomous mammals are animals of the class Mammalia that produce Venom, which they use to kill or disable prey or to defend themselves from predators 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. For a topic outline on this subject see List of basic Australia topics. The 20 cent coin of the Australian decimal currency system was issued with conversion to Decimal currency on 14 February 1966, replacing the florin

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.

Taxonomy and etymology

When the Platypus was first discovered by Europeans in 1798, a pelt and sketch were sent back to the United Kingdom by Captain John Hunter, the second Governor of New South Wales. In Mammals pelage is the Hair, Fur, or Wool that covers the Animal. The Kingdom of Great Britain, also known as the United Kingdom of Great Britain, was a State in northwest Europe, in existence from 1707 to 1800 Vice-Admiral John Hunter, RN ( 29 August 1737 &ndash 13 March 1821) was a British naval officer and colonial ^[4] The British scientists were at first convinced that the attributes must have been a hoax. ^[3] 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. George Shaw ( December 10, 1751 - July 22, 1813) was an English Botanist and Zoologist. Robert Knox MD FRCSEd FRSEd ( 4 September, 1791 &ndash 20 December, 1862) was a Scottish surgeon Taxidermy ( Greek for "skin arrangement" is the art of mounting or reproducing Animals for display (e ^[5] 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. ^[3]

The common name, Platypus, is Latin derived from the Greek words πλατύς ("platys", flat, broad) and πους ("pous", foot), meaning "flat foot". ^[6] 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). Linnaean taxonomy is a method of classifying living things originally devised by (and named for Carolus Linnaeus, although it has changed considerably since his time Ambrosia beetles are beetles of the Weevil subfamilies Scolytinae and Platypodinae ( Coleoptera, Curculionidae) which live in ^[7] It was independently described as Ornithorhynchus paradoxus by Johann Blumenbach in 1800 (from a specimen given to him by Sir Joseph Banks)^[8] and following the rules of priority of nomenclature it was later officially recognised as Ornithorhynchus anatinus. Johann Friedrich Blumenbach ( May 11, 1752 – January 22, 1840) was a German doctor and Physiologist, Sir Joseph Banks 1st Baronet, GCB, PRS (13 February 1743 &ndash 19 June 1820 was an English naturalist, botanist and patron of ^[7] The scientific name Ornithorhynchus is derived from ορνιθόρυνχος ("ornithorhynkhos"), which literally means "bird snout" in Greek, and anatinus which means "duck-like" in Latin. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome.

There is no universally agreed upon plural of "platypus" in the English language. Scientists generally use "platypuses" or simply "platypus". Colloquially, "platypi" is also used for the plural, although this is pseudo-Latin;^[3] the Greek plural would be "platypodes". Dog Latin or mock-Latin refers to the creation of a Phrase or Jargon in imitation of Latin, often by directly translating English Early British settlers called it by many names, such as watermole, duckbill, and duckmole. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located A settler is a person who has migrated to an area and established permanent residence there often to colonize the area ^[3] The name "Platypus" is often prefixed with the adjective "duck-billed" to form Duck-billed Platypus, despite there being only one species of Platypus. ^[9]

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. Fur is a body hair of any non-human Mammal, also known as the Pelage. ^[3][7] The Platypus uses its tail for storage of fat reserves (an adaptation also found in animals such as the Tasmanian Devil^[10] and fat-tailed sheep). The Tasmanian Devil ( Sarcophilus harrisii) also referred to simply as "the devil" is a carnivorous Marsupial now found in the wild only in The fat-tailed sheep is a category of Domestic sheep that comprise approximately 25% of the world Sheep population (Davidson 1999 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. ^[7] 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. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Anatomy Stegosaurus --> Beaks can vary significantly in size and shape from species to species 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. ^[7] Platypuses have been heard to emit a low growl when disturbed and a range of other vocalisations have been reported in captive specimens. ^[3]

A colour print of platypuses from 1863

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). ^[7] 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. ^[11]

The Platypus has an average body temperature of 31–32 °C (88–90 °F) rather than the 37 °C (100 °F) typical of placental mammals. Core temperature, also called core body temperature, is the operating Temperature of an Organism, specifically in deep structures of the body such as the See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals ^[12] 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. ^[13][14]

Modern Platypus young have three-cusped molars which they lose before or just after leaving the breeding burrow;^[15][16] adults have heavily keratinised pads in their place. Molars are the rearmost and most complicated kind of Tooth in most Mammals In many mammals they grind food hence the Latin name mola, " Millstone ^[7] The Platypus jaw is constructed differently from that of other mammals, and the jaw opening muscle is different. The jaw is either of the two opposable structures forming or near the entrance to the Mouth. ^[7] 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. The middle ear is the portion of the ear internal to the Eardrum, and external to the Oval window of the Cochlea. Cynodonts, or 'dog teeth' are a taxon of Therapsids which includes modern mammals and their extinct close relatives Synapsids ('fused arch' also known as theropsids ('beast face' are a class of Animals that includes Mammals and everything closer to mammals than However, the external opening of the ear still lies at the base of the jaw. ^[7] The Platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammals. An interclavicle is a bone which in most Tetrapods, is located between the Clavicles. ^[7] It has a reptilian gait, with legs that are on the sides of the body, rather than underneath. Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers ^[7]

Venom

Main article: Platypus venom

The calcaneus spur found on the male's hind limb is used to deliver venom. The Platypus is one of the few mammals to produce Venom. The male has a pair of spurs on the hind limbs through which it delivers a cocktail of poisons that while excruciatingly

The male Platypus has ankle spurs which produce a cocktail of venom, composed largely of defensin-like proteins (DLPs), which is unique to the Platypus. Defensins are small (15-20 residue) Cysteine -rich Cationic Proteins found in both Vertebrates and Invertebrates They are Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl ^[17] Although powerful enough to kill smaller animals,^[17] the venom is not lethal to humans, but is so excruciating that the victim may be incapacitated. Oedema rapidly develops around the wound and gradually spreads throughout the affected limb. Oedema (or Edema in American English formerly known as dropsy or hydropsy, is the increase of Interstitial fluid in any organ &mdash swelling 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. Hyperalgesia is an increased sensitivity to Pain, which may be caused by damage to Nociceptors or Peripheral nerves. ^[18][19] Venom is produced in the 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. In contrast to Tubular glands, in the second main variety of gland the secretory portion is enlarged and the lumen variously increased in size The female Platypus, in common with echidnas, has rudimentary spur buds which do not develop (dropping off before the end of their first year) and lack functional crural glands. ^[7]

The venom appears to have a different function from those produced by non-mammalian species: its effects are not 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. ^[17]

Electrolocation

Monotremes (see also echidna for the other species) 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. Echidnas (ɨˈkɪdnə also known as spiny anteaters, are four extant Mammal species belonging to the Tachyglossidae family of the Electroreception, sometimes written as electroception, is the biological ability to perceive Electrical impulses It is particularly common among aquatic creatures The Platypus' electroreception is the most sensitive of any monotreme. ^[20]

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. Electroreception, sometimes written as electroception, is the biological ability to perceive Electrical impulses It is particularly common among aquatic creatures A mechanoreceptor is a Sensory receptor that responds to mechanical pressure or distortion 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 cerebral cortex is a structure within the Brain that plays a key role in Memory, Attention, perceptual Awareness, Thought, 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. Somatotopic arrangement is the maintenance of spatial organisation within the Central nervous system. A cortical homunculus is a physical representation of the Primary motor cortex, i ^[21][22]

The Platypus can determine the direction of an electric source, perhaps by comparing differences in signal strength across the sheet of electroreceptors. In Telecommunications, particularly in Radio, signal strength refers to the magnitude of the Electric field at a reference point that is a significant distance 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. ^[20]

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). ^[20] 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. ^[23]

Ecology and behaviour

The platypus is very difficult to spot even on the surface of a river.

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. Tasmania is an Australian island and state of the same name It is located south of the eastern side of the Continent, being separated from it by Bass The Australian Alps are the highest Mountain ranges of mainland Australia. Tropical rainforests are generally found near the Equator. They are common in Asia, Australia, Africa, South America, Central Queensland is a state of Australia, occupying the north-eastern corner of the mainland continent This article is about the peninsula located in the Australian state of Queensland; it should not be confused with either Yorke Peninsula in South Australia ^[24] Inland, its distribution is not well known: it is extinct in South Australia (barring an introduced population on Kangaroo Island)^[25] 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. South Australia is a state of Australia in the southern central part of the country Kangaroo Island is Australia 's third largest Island - after Tasmania and Melville Island. The Murray-Darling Basin is 3375km long drains one-seventh of the Australian land mass and is currently by far the most significant agricultural area in Australia Water quality is the physical chemical and biological characteristics of Water in relationship to a set of standards Irrigation is an artificial application of water to the soil usually for assisting in growing crops ^[26] 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). The Maribyrnong River rises about 50 km north of Melbourne Victoria (Australia, near Mount Macedon. ^[27]

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. Mortality rate is a measure of the number of Deaths (in general or due to a specific cause in some population scaled to the size of that population per unit time ^[7] Natural predators include snakes, water rats, goannas, hawks, owls and eagles. A snake is an elongate Reptile of the suborder Serpentes Like all reptiles snakes are covered in scales. The Rakali ( Hydromys chrysogaster) also known as the Native Water Rat or Water Rat, is an Australian native Rodent. Goanna is the name used to refer to any number of Australian Monitor lizards of the genus Varanus, as well as to certain species from Southeast The term hawk can be used in several ways In strict usage in Europe and Asia, to mean any of the Species in the Subfamily The Owls are an order of birds of prey. Most are Solitary, and nocturnal, with some exceptions (e Eagles are large birds of prey which are members of the Bird order Falconiformes and family Accipitridae, and belong to several genera Low Platypus numbers in northern Australia are possibly due to predation by crocodiles. A crocodile is any Species belonging to the family Crocodylidae (sometimes classified instead as the Subfamily Crocodylinae) ^[28] The introduction of red foxes as a predator for rabbits may have had some impact on its numbers on the mainland. The Red Fox ( Vulpes vulpes) is a Mammal of the order Carnivora. Rabbits are small Mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world ^[11] The Platypus is generally regarded as nocturnal and crepuscular, but individuals are also active during the day, particularly when the sky is overcast. As an Animal behavior, nocturnality describes sleeping during the Daytime and being active at Night - the opposite of the diurnal Crepuscular is a term used to describe animals that are primarily active during Twilight, hence at Dawn and at Dusk. ^[29][30] 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. "Riverine" redirects here For the use of that term in Maritime geography, see there "Riparian" redirects here For the legal doctrine see " Riparian water rights. ^[30] 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. ^[31]

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. ^[32] 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. ^[33] The species is endothermic, maintaining its body temperature about 32 °C, lower than most mammals, even while foraging for hours in water below 5 °C (41 °F). In Biology, a warm-blooded Animal species is one whose members maintain thermal Homeostasis; that is they keep their body temperature at a roughly constant ^[7]

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. ^[34][35] 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. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting The annelids, collectively called Annelida (from Latin anellus "little ring" are a large phylum of Animals comprising A larva ( Latin; plural larvae) is a juvenile form of Animal with indirect development, undergoing Metamorphosis (for example True shrimp are swimming decapod Crustaceans classified in the Infraorder Caridea, found widely around the world in both fresh It utilizes cheek-pouches to carry prey to the surface where they are eaten. ^[32] 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. ^[34] 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. Camouflage is a method of cryptic or concealing coloration that allows an otherwise visible Organism ^[32]

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. ^[7][17] Mindful of the high cost of wiring England based on the cost per word, Caldwell famously but tersely wired London, "Monotremes oviparous, ovum meroblastic. London ( ˈlʌndən is the capital and largest urban area in the United Kingdom. " 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, with mating occurring between June and October, with some local variation taking place in populations across the extent of its range. The breeding season is the most suitable season usually with favorable conditions and abundant food and water for breeding among some wild animals and birds (wildlife ^[28] 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. Polygyny (which comes from neo- Greek: πολύ poly "many" + γυνή gyny "woman" is a specific form of Polygamy, ^[36] 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. ^[36]

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). ^[37] 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. ^[3]

The female Platypus has a pair of ovaries but only the left one is functional. "Ovaria" redirects here This is also a proposed section and a Synonym of Solanum. ^[29] It lays one to three (usually two) small, leathery eggs (similar to those of reptiles), that are about 11 mm (7/16 inches) in diameter and slightly rounder than bird eggs. ^[38] 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 21 days externally). ^[29] 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. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The yolk sac is the first element seen in the Gestational sac during Pregnancy, usually at 5 weeks Gestation. The yolk is absorbed by the developing young. ^[39] During the second, the digits develop, and in the last, the egg tooth appears. In some egg -laying Animals the egg tooth is a small sharp cranial protuberance used by Offspring to break or tear through the egg's surface during ^[40]

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. Mammary glands are the organs that in Mammals produce Milk for the sustenance of the young 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. ^[3][28] 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. ^[41] 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. ^[28]

Evolution

Platypus skeleton

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 quasi-reptilian, still endure. Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers ^[42] In fact, 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. Marsupials are an Infraclass of Mammals characterized by a distinctive pouch (called the marsupium) in which females carry their young through ^[43][42] 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. William King Gregory ( 19 May 1876 &ndash 29 December 1970) was an American Zoologist, renowned as a Primatologist ^[42][44]

The oldest discovered fossil of the modern Platypus dates back to about 100,000 years ago, during the Quaternary period. Overview The term Quaternary ("fourth" was proposed by Giovanni Arduino in 1759 for alluvial deposits in the Po river valley in northern The extinct monotremes (Teinolophos and Steropodon) were closely related to the modern Platypus. Teinolophos trusleri was a Prehistoric Species of Monotreme, or egg-laying Mammal. Steropodon galmani was a prehistoric Species of Monotreme, or egg-laying Mammal, that lived during the middle Albian stage ^[44] 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. Molars are the rearmost and most complicated kind of Tooth in most Mammals In many mammals they grind food hence the Latin name mola, " Millstone ^[15] 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. The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of 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). Obdurodon is an extinct Monotreme Genus containing three species For a topic outline on this subject see List of basic Argentina topics. Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a ^[15][45]

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. Theria (ˈθɪərɪə from the Greek θηρίον, wild beast is a subclass of Mammals ref> that give birth to live young without In 2004, researchers at the Australian National University discovered the Platypus has ten sex chromosomes, compared with two (XY) in most other mammals (for instance, a male Platypus is always XYXYXYXYXY). Research is defined as Human activity based on Intellectual application in the investigation of Matter. The Australian National University, commonly abbreviated to ANU, is a public Research university situated in Canberra, Australia. A sex-determination system is a biological system that determines the development of sexual characteristics in an Organism. ^[46] Although given the XY designation of mammals, the sex chromosomes of the Platypus are more similar the ZZ/ZW sex chromosomes found in birds. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. ^[47] It also lacks the mammalian sex-determining gene SRY, meaning that the process of sex determination in the Platypus remains unknown. SRY ( Sex-determining Region Y) is a Sex -determining Gene on the Y chromosome in the Therians (placental mammals and marsupials ^[48] 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. Nature is a prominent Scientific journal, first published on 4 November 1869 Events 589 - Reccared summons the Third Council of Toledo 1450 - Jack Cade's Rebellion: Kentishmen 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common ^[47] More than 80 percent of the Platypus' genes are common to the other mammals whose genomes have been sequenced.

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. ^[30] The species was extensively hunted for its fur until the early years of the 20th century and, although protected throughout Australia in 1905,^[41] up until about 1950 it was still at risk of drowning in the nets of inland fisheries. ^[26] 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. ^[2] The IUCN lists the Platypus on its Red List as Least Concern. The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List) created in 1963 is the world's most comprehensive inventory of the global ^[2]

A depiction of a Platypus from a book for children published in Germany in 1798

Platypuses generally suffer from few diseases in the wild, however there is widespread public concern in Tasmania about the potential impacts of a disease caused by the fungus Mucor amphibiorum. The disease (termed Mucormycosis) only affects Tasmanian platypuses; it has not been observed in platypuses in mainland Australia. Zygomycosis is the broadest term to refer to an infection caused by Fungi of the Zygomycetes order Affected platypuses can develop ugly skin lesions or ulcers on various parts of the body including their backs, tails and legs. Mucormycosis can kill platypuses, with death arising from secondary infection and by affecting the animals’ ability to maintain body temperature and forage efficiency. 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 Platypus, as well as the mechanism of transmission and current spread of the disease. The University of Tasmania (also abbreviated as UTAS UTas or Tas Uni is an Australian University, with three campuses in Tasmania. ^[49] Until recently the introduced Red Fox (Vulpes vulpes) was confined to mainland Australia, but growing evidence now indicates that it is present in low numbers in Tasmania. The Red Fox ( Vulpes vulpes) is a Mammal of the order Carnivora. ^[50] This efficient, adaptable predator is recognised in Australia as the single most devastating introduced pest and threat to Australia's native land animals. It would be a disaster to native biodiveristy if it was allowed to establish in Tasmania. Tasmania arguably represents the best habitat for platypus in Australia and probably has the highest numbers of platypus of any state. Fungal disease and fox predation may represent significant challenges to these iconic animals.

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 National Geographic Magazine is the official journal of the National Geographic Society. This is a difficult task, and only a few young have been successfully raised since — notably at Healesville Sanctuary in Victoria. Healesville Sanctuary, or the Sir Colin MacKenzie Fauna Park, is a Zoo specializing in native Australian animals 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. David Howells Fleay ( 6 January 1907 Ballarat, Victoria &ndash 7 August 1993) was an Australian naturalist 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. The David Fleay Wildlife Park is located in Burleigh Heads, a suburb of the Gold Coast, Queensland, Australia. Burleigh Heads is a suburb of the Gold Coast in Queensland, Australia. This article is about the Australian city Gold Coast For other uses see Gold Coast. ^[51] 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. Taronga Zoo is the city Zoo of Sydney, New South Wales, Australia. Sydney (ˈsɪdniː is the most populous city in Australia, with a Metropolitan area population of approximately 4 ^[52]

Cultural references

The Australian 20 cent coin features a Platypus

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). God is the principal or sole Deity in Religions and other belief systems that worship one deity. Dogma is a 1999 Comedy film, written and directed by Kevin Smith, who stars in the film along with Ben Affleck, Matt Damon 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,^[53] "Expo Oz" the Platypus was the mascot for Expo '88 which was held in Brisbane in 1988,^[54] and Hexley the Platypus is the mascot for Apple Computer's BSD-based Darwin operating system, Mac OS X. "I am proud and happy to proclaim that you have presented to the world the best Olympic Games ever Kookaburras (genus Dacelo) (or Cookaburras are large to very large (total length 28-42 cm/11-17 in terrestrial Kingfishers native Expo '88, officially known as 'World Expo 88' was a World's Fair held in Brisbane, Queensland, Australia during a six month period between Brisbane ( is the state capital of Queensland. Brisbane is the third most populous city in Australia and the most populous city of Queensland Hexley is the Mascot of the Open source operating system Darwin, which is the core of Apple Inc 's Mac OS X operating system Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics Darwin is an open source UNIX -based computer Operating system released by Apple Inc ^[55]

The Platypus has also been featured in songs, such as Green Day's Platypus (I Hate You), and frequently appears as a character in children's programmes, for example, the Platypus Family on Mister Rogers’ Neighborhood, and Ovide, the star of the cartoon Ovide and the Gang. Green Day is an American rock trio Mister Rogers' Neighborhood or Mister Rogers is an American Children's television series that was created and hosted by La Bande à Ovide, aka Ovide and the Gang, was a 1980s animated TV show produced by the Canadian animation studio CinéGroupe ^[56]

See also

• Australian fauna
• List of venomous mammals
• Henry Burrell

Notes

References

Books

Documentary

External links

• Nature.com "Top billing for platypus at end of evolution tree" 7 May 2008
• PBS.org
• Platypus-Evolution and Conservation