Platypus

Australian Aboriginal people have referred to the platypus in various ways depending on Australian indigenous languages and dialects. Among the names found: boondaburra, mallingong, tambreet, watjarang (names in Yass, Murrumbidgee, and Tumut), dulaiwarrung or dulai warrung (Woiwurrung language, Wurundjeri, Victoria), djanbang (Bundjalung, Queensland), etc. The name chosen and approved in Palawa kani (reconstructed Tasmanian language) is larila. 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. British scientists' initial hunch was that the attributes were a hoax. 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, and Robert Knox believed—because it arrived in England via the Indian Ocean—that it might have been created by Chinese sailors. from ( 'broad, wide, flat') and ( 'foot'). Shaw initially assigned the species the Linnaean name Platypus anatinus when he described it, and following the rules of priority of nomenclature, it was later officially recognised as Ornithorhynchus anatinus. Various dictionaries list "platypuses" or simply "platypus" as the plural. Alternatively, the term "platypi" is also used for the plural, although this is a form of pseudo-Latin; going by the word's Greek roots the plural would be "platypodes". The scientific name Ornithorhynchus anatinus literally means 'duck-like bird-snout', and the word ( 'snout', 'beak'). Its species name is derived from Latin ('duck-like') from 'duck'. The platypus is the sole living representative or monotypic taxon of its family (Ornithorhynchidae). platypus-plate.jpg|A book for children published in Germany in 1798 Platypus (Ornithorhynchus anatinus). First Description 1799.jpg|Illustration from the first scientific description in 1799 platypus-sketch.jpg|Colour print from 1863 == Description ==

Most of the platypus' small streamlined body is covered with short, dense, brown fur that traps a layer of insulating air to keep the animal warm, both in and out of water. The fur coat is waterproof and consists of flattened guard hairs and curvy underfur hairs. It is also unique among mammal in having hair pigmentation melanosomes that are hollow. The duck-like bill consists of a long snout and lower jaw which is covered in soft skin. The nostrils are located near the tip of the snout's dorsal surface, while the eyes and ears are just behind the snout in a groove which closes underwater. The platypus has an interclavicle in the shoulder girdle, a trait which they share in common with reptiles. Adult platypuses lack teeth and instead have heavily keratinised food-grinding pads. They lose their teeth around the time they leave their natal burrow.. However, the platypus’s digestive tract has a pouch-like section that assists with nutrient absorption in the intestines . Male platypuses have an average length of and weight of , while females are smaller with an average length of and weight of . The platypus has an average body temperature of about , lower than the typical of placental mammals. Research suggests this has been a gradual adaptation to harsh environmental conditions among the few marginal surviving monotreme species, rather than a general characteristic of past monotremes. The platypus has a single opening, called a cloaca, for both the reproductive and waste systems. The female has two ovaries, with the right one being non-functional, and teats are absent. known to have a sense of electroreception. The platypus relies on electrolocation when feeding, as the eyes, ears, and nose are closed while underwater. The 40,000 electroreceptors are arranged in rows in the skin of the bill from front to back, while mechanoreceptors for touch are uniformly distributed across the bill. The electrosensory area of the cerebral cortex is in the tactile somatosensory area, and some cortical cells receive input from both electroreceptors and mechanoreceptors, suggesting the platypus feels electric fields as touches. These receptors in the bill dominate the somatotopic map of the platypus brain, in the same way human hands dominate the Penfield homunculus map. The platypus can feel the direction of an electric source, perhaps by comparing differences in signal strength across the array of electroreceptors, enhanced by the characteristic side-to-side motion of the animal's head while hunting. It may also be able to determine the distance of moving prey via the timing difference between electrical and mechanical pressure sensations. The eyes of the platypus have basal traits also found in lungfish and amphibians, such as scleral cartilage, double cones, and droplets. The platypus's eyes are small and shut under water, though several features indicate its ancestors relied on vision. As with other aquatic mammals, the eye has a flattened cornea and surrounding lens, while the posterior surface of the lens is sharply inclined. A temporal (ear side) concentration of retinal ganglion cells, important for binocular vision, indicates a vestigial role in predation, though the actual visual acuity is insufficient for such activities. Limited acuity is matched by 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. This contrasts with the small number of electroreceptors in the short-beaked echidna, which dwells in dry environments, while the long-beaked echidna, which lives in wetter habitats is intermediate between the other two monotremes. Venom While both male and female platypuses are born with back ankle spurs, only the males retain them into adulthood. The spurs of the male inject venom, which is powerful enough to inflict pain in humans. Starting from the wounded area, the affected limb develops edema (swelling via fluid buildup) which can lead to an excruciating hyperalgesia (heightened sensitivity to pain) that can last as long as months. The venom is composed largely of defensin-like proteins (DLPs) produced by the immune system, some of which are unique to the species. It is produced in kidney-shaped alveolar glands located in each of the thighs of the hind limbs and connected to the spur. The venomous spurs of male platypuses serve as weapons in battles with other males for breeding. ==Distribution and habitat==

The platypus is native to the freshwaters of eastern Australia, from Queensland to Tasmania (including King Island but not the Furneaux Group). It was believed to be extinct on the South Australian mainland, with the last sighting recorded at Renmark in 1975. Platypuses were captively bred at Warrawong Sanctuary in 1990-91. In October 2020 a nesting platypus was filmed in the wild after the previously abandoned Sanctuary reopened. There is a population on Kangaroo Island introduced in the 1920s, said to stand at 150 individuals in the Rocky River region of Flinders Chase National Park. In the 2019–20 Australian bushfire season, large portions of the island burned, decimating wildlife. However, SA Department for Environment and Water recovery teams worked to restore their habitat, with a number of sightings reported by April 2020. The platypus has almost disappeared from the Murray–Darling Basin, possibly due to poor water management. Platypuses can be found in a variety of freshwater habitats including rivers, streams, lakes and lagoon-like pools. The surrounding terrestrial environment includes tropical rainforests and colder alpine areas. ==Ecology and behaviour==

, Australia The platypus is semiaquatic and requires permanent freshwater habitat. It can maintain its relatively low body temperature when feeding in colder depths of below . The species is mainly nocturnal but is also active at dusk during the summer and daytime during winter. A platypus may spend half the day in water and then retreat into its burrow, which is constructed by digging into the bank. These vary between simple resting banks and complex nesting/breeding burrows. It may have a range of up to , with a male's home range overlapping those of three or four females. Platypuses are not very vocal; they have been recorded to growl when disturbed and squeak when feeling pain. They are preyed upon by Murray cod, eels, carpet snakes, goannas, eagles, crocodiles, and foxes. Internally, the platypus may host protozoans, trematodes, and nematodes. Reproduction Platypuses are seasonal breeders, with the more southerly populations breeding later in the year than those further north; those in New South Wales mate during fall and winter. Females are believed to become sexually mature at two years of age and continue to breed beyond nine years. The female retreats into a nesting/breeding burrow made of grass, which can be long, to lay eggs and raise young. The female normally lays two small, leathery eggs about long. The eggs develop in utero for about twenty-eight days, followed by a ten day external incubation. With no teats, the milk is released through pores in the skin from which the young lap it up in her fur. Hatched young also have a remnant yolk sac which disappears within four days. By then, they are fully covered in fur and may be around 67% the weight of an adult and 80% the length. They are fully grown at around two years. == Evolution ==

}} In separate publications in 1934, 1947, and 1951, William King Gregory theorised that placental mammals and marsupials may have diverged earlier, and a subsequent branching divided the monotremes and marsupials. Later research and fossil discoveries have suggested this is incorrect. 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. Both molecular clock and fossil dating suggest that the platypus split from echidnas around 19–48million years ago. The oldest discovered fossil of the modern platypus dates back to about 100,000 years ago during the Quaternary period, though a limb bone of Ornithorhynchus is known from Pliocene-epoch strata. The extinct monotremes Teinolophos, Steropodon and Kollikodon from the Cretaceous period are considered to be basal to the platypus and echidnas. The remains of Steropodon were discovered in New South Wales, 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 that, while they have three cusps, they evolved under a separate process. The fossil jaw of Teinolophos is elongated but unlike the modern platypus (and echidnas), lacks a beak. In 2024, Late Cretaceous (Cenomanian)-aged fossil specimens of early platypus relatives were recovered from the same rocks as Steropodon, including the basal Opalios and the more derived Dharragarra, the latter of which may be the oldest member of the platypus family Ornithorhynchidae, as it retains the same dental formula found in Cenozoic platypus relatives. Monotrematum and Patagorhynchus, also fossil relatives of the platypus, are known from the latest Cretaceous (Maastrichtian) and the mid-Paleocene of Argentina, indicating that some monotremes managed to colonize South America from Australia when the two continents were connected via Antarctica. These are also considered potential members of the platypus Ornithorhynchidae. The loss of teeth in the modern platypus has long been enigmatic, as a distinctive lower molar tooth row was present in its lineage for over 95 million years. Even its closest relative, Obdurodon, which otherwise closely resembles the platypus, retained this tooth row. More recent studies indicate that this tooth loss was geologically a very recent event, occurring only around the Plio-Pleistocene about 2.5 million years ago, when the rakali, a large semiaquatic rodent, colonized Australia from New Guinea. The platypus, which previously fed on a wide array of hard and soft-bodied prey, was outcompeted by the rakali for hard-bodied prey such as crayfish and mussels. This competition may have selected for the loss of teeth in the platypus and their replacement by horny pads, as a way of specializing for softer-bodied prey, over which the rakali did not compete. The platypus genome also has both reptilian and mammalian genes associated with egg fertilisation. 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. A draft version of the platypus genome sequence was published in Nature in May 2008, revealing both reptilian and mammalian elements, as well as two genes previously found only in non-mammalian vertebrates. More than 80% of the platypus's genes exist in other amniotes whose genomes have been compared. == Conservation ==

The International Union for Conservation of Nature categorised the platypus as "near threatened" in 2016, and throughout Australia by 1912, it continues to drown in the nets of inland fisheries. The use of "opera house traps" by recreational fishers for catching yabbies is banned in the ACT, South Australia, Tasmania and Victoria, and restricted in NSW and Queensland, due to the traps drowning non-targeted species including platypuses. The platypus was listed as endangered is South Australia, under the National Parks and Wildlife Act 1972. In November 2020 a recommendation was made to list the platypus as a vulnerable species across all states. In January 2021, Victoria officially adopted the vulnerable species designation, under the state's Flora and Fauna Guarantee Act 1988. The platypus is not covered under the federal EPBC Act. The platypus continues to be adversely affected by habitat disruption caused by dams, pollution, urban expansion, and urban runoff. Droughts and the demands for water for human use are also considered threats. A November 2020 report by scientists from the University of New South Wales, funded by a research grant from the Australian Conservation Foundation in collaboration with the World Wildlife Fund Australia and the Humane Society International Australia revealed that over the past thirty years platypus habitat in Australia has dropped by 22%, and supported listing the platypus as a threatened species under the EPBC Act, as the declines have been mostly in the Murray–Darling basin and NSW in general. including twins. In 1990-91, there was successful breeding of platypuses at Warrawong Sanctuary. and the facility has since bred more platypuses to be released into the wild in NSW.{{cite web|title=First ever platypus translocation nsw results breeding success == Human interactions ==

Usage Aboriginal Australians hunted and ate platypuses, particularly for their fatty nutritious tails, while, after colonisation, Europeans killed them for fur from the late 19th century until 1912, when it was prohibited by law. In addition, European researchers captured and killed platypus or removed their eggs, partly in order to increase scientific knowledge, but also to gain prestige and outcompete rivals from different countries. Australia gave live platypuses as diplomatic gifts to Allied nations as part of an initiative to increase military assistance. One of which was intended as a gift to Winston Churchill died from neglect while en route. Aboriginals from the upper Darling River region have a story of a large water-rat called Biggoon who kidnaps a duck what wandered too far from its tribe. After managing to escape, she returned and laid two eggs which hatched the first platypuses. They were all exiled and went to live in the mountains. In another story from the upper Darling, 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, and wished to remain friends with all of those groups. The platypus is also featured as a totem for some Aboriginal peoples, which is to them "a natural object, plant or animal that is inherited by members of a clan or family as their spiritual emblem", and the animal holds special meaning for the Wadi Wadi people at the Murray River. Because of their cultural significance and importance in connection to country, the platypus is protected and conserved by these Indigenous peoples. The platypus has often represented Australia's cultural identity and its image has also been used for stamps and currency and as a mascot in the 2000 Summer Olympics in Sydney. Platypus cape unknown tasmania.jpg|Platypus fur cape made in 1890, now in the National Gallery of Victoria "Nam Sang Woo Safety Matches" platypus matchbox label art - from, Collectie NMvWereldculturen, TM-6477-76, Etiketten van luciferdoosjes, 1900-1949 (cropped).jpg|Early 20th-century matchbox label Australianstamp 1551.jpg|9d postage stamp from 1937 == See also ==