The duck-billed platypus is another name for the platypus. The duck-billed platypus is a semi-aquatic, egg-laying mammal found exclusively in eastern Australia, including Tasmania. It is among the five monotreme species that still exist.
It’s one of the few animals that give birth to eggs rather than live babies. It uses electrolocation to detect prey. The male platypus possesses a spike on his hind foot that carries venom. It is capable of causing considerable pain in humans, making it one of the few venomous mammals.
The paddle is the word used to refer to a platypus group. They are also known as duckbills due to the similarity of their bill to that of a duck.
When European naturalists first saw the duck-billed platypus, they were puzzled. It laid eggs and had a tail like a beaver’s. It was footed like an otter and was a duck-billed creature. The first scientists to study a preserved platypus body in 1799 declared it a forgery, made up of many animals sewed together.
The duck-billed platypus’ distinctive characteristics make it a significant subject in evolutionary biology. It is also a well-known and iconic emblem of Australia. It has cultural significance for various Australian Aboriginal peoples, who used to hunt the mammal for meat.
The duck-billed platypus is the animal symbol of the state of New South Wales. It has also been featured as a mascot at national events. It also appears on the back of the Australian twenty-cent piece.
Humans used to hunt the duck-billed platypus for its fur until the early twentieth century, but it is now protected across its habitat. Even though captive breeding operations have had little success and the platypus is prone to contamination, it is not in immediate danger.
The IUCN lists the species as near-threatened. However, a study released in November 2020 suggested that it be raised to threatened species under the federal EPBC Act owing to habitat degradation and dwindling populations across the country.
Description
The duck-billed platypus’s body and broad, flat tail are covered with dense, brown bio fluorescent hair that captures a layer of insulating air to keep it warm. The fur is waterproof and has a mole-like feel to it. The platypus stores fat reserves in its tail. This adaption is also seen in animals like the Tasmanian devil.
The duck-billed platypus has webbed feet. The bill is formed by the delicate skin covering the extended snout and lower jaw.
The nostrils are on the snout’s rear surface. At the same time, the eyes and ears are in a groove set back from it. When swimming, this groove is closed. When disturbed, platypuses have been observed to emit a deep growl and a variety of other voices in captive animals.
A male platypus is bigger than a female, with a weight ranging from 0.7 – 2.4 kg. Males average 50 centimeters or 20 inches overall length, while females approximate 43 centimeters or around 17 inches. They vary widely in normal size from location to region. This trend appears to defy any climate norm and might be attributable to other exogenous conditions like hunting and human encroachment.
They have a body temperature of roughly 32 degrees Celsius. This is contrary to other mammals with a body temperature of 37 degrees Celsius.
Young duck-billed platypus has three teeth in their upper jaw teeth: one premolar and two molars. Duck-billed platypus has three teeth in their lower jaw and three molars. They lose these before or after they leave the breeding burrow. Adults have ceratodontes, which are strongly keratinized pads to ground food.
The jaw of the platypus is built differently than that of other mammals, as is the mouth-opening muscle. The small bones that transmit sound in the inner ear are entirely integrated into the skull in all-natural mammals rather than resting in the jaw in pre-mammalian synapsids. The ear’s external opening, on the other hand, remains near the base of the jaw.
The shoulder girdle in duck-billed platypus possesses additional bones, such as an interclavicle, that are not present in other mammals. The bones of the platypus develop osteosclerosis, which is meant to increase the density of the bones to provide weight.
The legs are on the sides of the body rather than below, giving it a reptile-like motion. It walks on its front foot, knuckle-walking to prevent the webbing between its toes when on land.
Venom
Male and female platypuses have ankle spurs; however, only the spurs on the back ankles of male platypuses produce venom. This venom is made up mostly of defensin-like proteins (DLPs). Three of these DLP’s are unique to the duck-billed platypus.
The immunity of the platypus produces the DLPs. Defensins are those proteins that cause lysis in dangerous bacteria and viruses. These proteins are also transformed into venom in platypuses for protection.
Although the venom is potent enough to kill smaller animals like dogs, it is not dangerous to people. But it causes such excruciating pain that it renders the victim unconscious.
Oedema forms around the lesion quickly and then spread throughout the injured leg. The case studies and anecdotal evidence show that the pain develops into long-lasting hyperalgesia. This means a heightened sensitivity to pain that can last for days or even months.
The male’s crural glands, which are kidney-shaped alveolar glands attached to a calcaneus spur on each hind limb via a thin-walled duct, are responsible for generating venom. Female platypus has rudimentary spur buds that do not mature and end up falling off before the completion of their first year. Also, there is no functioning in the crural glands.
The venom seems to serve a different purpose than that of non-mammalian animals. Its effects aren’t life-threatening in humans. However, they’re despite that strong enough to damage the victim gravely.
Because venom is primarily produced by males and production increases throughout the breeding season, it might be utilized as an aggressive weapon to demonstrate dominance during this time.
Electrolocation
Monotremes are known to have an electroreception sense aside from at least one dolphin species. This means they partly identify their prey by sensing electric fields created by muscle contractions. The duck-billed platypus has the most sensitive electroreception of any monotreme.
The electroreceptors are present in the skin of the bill of the platypus. They are arranged in rostrocaudal rows. The mechanoreceptors responsible for the feeling of touch are evenly distributed throughout the bill.
The tactile somatosensory region of the cerebral cortex houses the electrosensory area. Additionally, certain cortical cells get information from electroreceptors and mechanoreceptors, suggesting a strong relationship between the tactile and electric senses.
In the same way, human hands control the Penfield homunculus map, electroreceptors, and mechanoreceptors in the bill control the platypus brain’s map.
By evaluating variances in signal intensity throughout the sheet of electroreceptors, the platypus can detect the direction of an electric source. This would illustrate the animal’s unique side-to-side head movements while hunting.
The merging of electrosensory and tactile inputs in the cortex provides a method for determining the distance between prey that generates both electrical impulses and mechanical pressure pulses when they move. The platypus detects distance by analyzing the transmission timings of the two signals.
When the platypus dives, it shuts its eyes, ears, and nose to avoid being seen or smelled. Instead, as it digs in the bottom of rivers with its bill, its electroreceptors detect small electric currents created by its prey’s muscle contractions. This enables it to discriminate between living and inanimate items, which activate its mechanoreceptors continually.
Experiments have revealed that if a simple electric current is put through a “fake shrimp,” the platypus will react.
Monotreme electrolocation is thought to have developed for the animals to feed in murky waters. It may also be linked to tooth loss. The extinct Obdurodon was electroreceptive but hunted in open seas or oceans.
Eyes
The eyes of the duck-billed platypus also feature double cones, which are absent in most animals.
Although the platypus’ eyes are tiny and do not function underwater, numerous characteristics suggest that vision was crucial to its forefathers. The corneal and surrounding surfaces of the lens are flat, whereas the posterior surface is sharply curved, comparable to the eyes of other aquatic species like otters and sea lions.
While the accompanying visual acuity is insufficient for such activities, a temporal or ear side concentration of retinal ganglion cells, required for binocular vision, suggests a function in predating activities.
This poor understanding is complemented by a low cortical magnification, a tiny lateral geniculate nucleus, and a big optic tectum. These hints that, like in certain rodents, the visual midbrain plays a more essential function than the visual cortex.
These characteristics suggest that the platypus adapted to an aquatic and nocturnal lifestyle by developing its electrosensory system at the expense of its visual system. Compared to the short-beaked echidna’s small number of electroreceptors in dry environments, this is an evolutionary process. While the long-beaked echidna, which lives in wet areas, is intermediate between the two monotremes.
Biofluorescence
According to black light, the platypus shines a bluish-green tint when subjected to a fluorescence study published in 2020.
Distribution, Ecology, and Behavior
The platypus is semiaquatic, living in tiny streams and rivers from Tasmania’s icy highlands. It can also be found in the Australian Alps and the tropical rainforests of coastal Queensland as far north as the Cape York Peninsula’s base.
Its spread in the interior is unidentified. It was thought to be extinct on the South Australian continent, with the final sighting near Renmark in 1975.
The platypus is no longer visible in the Murray-Darling Basin’s major section. The reason for this can be the diminishing water quality that is caused by significant land clearance and irrigation systems. Its distribution along the coastal river systems is unexpected. It seems to be absent from some reasonably healthy rivers while being present in others, such as the lower Maribyrnong, that are severely damaged.
Platypuses in captivity have lived to be 17 years old. At the same time, the wild species have survived being captured at the age of 11 years old. Adult mortality rates in the wild appear to be less. Natural predators are snakes, water rats, hawks, owls, and eagles. Crocodile predation may be to blame for low platypus numbers in northern Australia.
The introduction of red foxes for hunting in 1845 may have influenced the mainland population. The platypus is known for being nocturnal and the one that appears in twilight or dusk. Although platypus is often active during the day, it happens when the sky is gloomy.
Its habitat spans rivers and riparian zones. These zones provide food for prey species and banks for resting and nesting tunnels. It ranges up to 7 kilometers, approximately 4.3 miles, with a male platypus’s home range covering three or four females.
The duck-billed platypus is a strong swimmer who spends a lot of time searching for food in the water. It swims distinctly and has no external ears. Although the platypus has webbed feet on all four legs, the hind feet, which are kept against the body, are utilized for steering in tandem with the tail. This makes it unique among mammals as it can accelerate itself while swimming by an alternate paddling motion of the front feet.
The species is endothermic; even while feeding for hours in the water below five °C, the species is endothermic. The duck-billed platypus maintains a body temperature of around 32 °C or 90 °F, which is lower than other mammals.
The duck-billed platypus dives usually last approximately 30 seconds, although they can last longer. Compared to a few other mammals who go longer than 40 seconds. It takes to recover at the surface between dives is usually between 10 and 20 seconds.
The duck-billed platypus retreats to a short, straight resting burrow with an oval cross-section when not in the water. This burrow is usually located along the riverbank and is frequently buried behind a protective tangle of roots.
A duck-billed platypus’s usual sleep period is estimated to be up to 14 hours per day, probably because it consumes crustaceans, which are heavy in energy.
Diet
The platypus is a carnivore that eats worms, insect larvae, freshwater shrimp, and freshwater crayfish, digs up with its nose, or captures while swimming. It carries prey to the level where it is devoured using its cheek pouches. The platypus must eat roughly 20 percent of its body mass each day, which necessitates it to spend an average of 12 hours per day searching for food.
Almost all animals digest their food using a stomach. The platypus, just like the spiny echidna, has a gullet. It is the passage through which food normally travels from the mouth to the stomach that contains links to its intestines. There is no need for a stomach to digest food.
Reproduction
When European naturalists first saw the duck-billed platypus, they were split on whether or not the female laid eggs. The species has a single breeding season. Their mating occurs between June and October, with considerable local variation across populations across its range.
Historical evidence, environmental statistics experiments, and basic population genetics research point to permanent and short-lived members of populations and a polygynous mating system. Females are considered to reach sexual maturity in their second year, and breeding has been proven in animals above nine.
The duck-billed platypus lives in a modest earth burrow about 30 cm, approximately 12 inches above the water level outside of the breeding season. After mating, the female digs a deeper, more complicated tunnel that may be up to 20 m or 65 ft long. These tunnels are blocked at intervals, which may protect against rising waters or predators.
The male refuses to help care for the young and withdraws to his year-long burrow. The female softens the burrow’s ground with the dead, folded, damp leaves and fills the nest at the tunnel’s end with leaf litter and reeds for bedding.
It lays one to three and typically two tiny, tough eggs around 11 mm (716 in) in diameter and somewhat rounder than bird eggs, comparable to those of reptiles.
The eggs need around 28 days to mature in the uterus, with just about ten days of external incubation, which takes one day in the tract and 21 days externally. The female coils over her eggs once they are laid. Three stages make up the incubation period.
The embryo has no functioning organs in the first stage and survives solely on the yolk sac. The growing young ingest the yolk. The fingers form during the second phase, and the egg tooth appears during the last phase.
Although there is no official name for duck-billed platypus young, “platypus” is often used informally.
Conservation
Status and threats
The duck-billed platypus still has the same broad range before the European colonization of Australia, except in South Australia. However, due to human habitat modification, local modifications and distribution fragmentation have been reported.
Its historical abundance is unclear, and its present abundance is difficult to estimate. However, it is thought to have dropped in numbers; it was still deemed widespread over much of its current range in 1998.
The species of the duck-billed platypus was heavily hunted for its fur until the early twentieth century. Despite being protected across Australia since 1905, it was at risk of drowning in inland fishing nets until approximately 1950.
In 2016, the International Union for Conservation of Nature reclassified it as “near threatened.” The species is legally protected; however, under the National Parks and Wildlife Act 1972, it is only classed as endangered in South Australia. The Flora and Fauna Guarantee Act, 1988 in Victoria, has advised that it be designated as a vulnerable species by 2020.
Habitat destruction
Because conservation efforts have been effective, the duck-billed platypus is not believed to be in immediate danger of extinction. Nonetheless, habitat disruption caused by dams, irrigation, pollution, netting, and trapping might hurt its habitat.
Drought-induced reductions in watercourse flow, water levels, and water extraction for industrial, agricultural, and household purposes are considered threats. The duck-billed platypus is listed as “Near Threatened” on the IUCN Red List as of 2016, when it was observed that populations had decreased by roughly 30% on average since European arrival. Although the species is endangered in South Australia, it is not protected under the federal EPBC Act.
Disease
Platypuses in the wild are largely disease-free. However, there was worry in 2008 in Tasmania about the possible effects of a disease caused by the fungus Mucor amphibious. Particularly Tasmanian platypuses are affected by the disease called mucormycosis, which has not been seen in mainland Australia platypuses.
Platypuses with the disease can develop skin sores or ulcers on their backs, tails, and legs, among other regions of their bodies. Platypuses can die from mucormycosis due to secondary infection and the animals’ inability to efficiently maintain body temperature and graze.
Platypus in wildlife sanctuaries
When an article was published in the National Geographic Magazine about the platypus and efforts to study and nurture it in captivity in 1939, it exposed the platypus to a large portion of the world. Nurturing the duck-billed platypus is a challenging undertaking. Moreover, a few young have been effectively reared since then, most notably at Victoria’s Healesville Sanctuary.
David Fleay created a platypusary, a replicated stream in a tank at the Healesville Sanctuary, where breeding was achieved in 1943. It was a key player in these efforts. Corrie, the first platypus “born” in captivity, was well-liked by the public. She fled from her prison into adjacent Badger Creek three months before a new “platypussary” after “aviary” opened in 1955 and was never found.
At his wildlife park in Burleigh Heads, Queensland, in 1972, he discovered a dead baby of around 50 days old, born in captivity.
With a comparable stream tank, Healesville replicated its success in 1998 and 2000. Platypus has been bred at Healesville regularly since 2008. In 2003, the Taronga Zoo in Sydney successfully produced twins, and breeding was successful again in 2006.
Usage by humans
Duck-billed platypuses were once sought for food by Aboriginal Australians because of their fatty tails as they were particularly nourishing. Still, Europeans hunted them for fur from the late 1800s until 1912, when it was illegal. Furthermore, European scientists abducted and killed platypus or collected their eggs, partially to further scientific understanding and earn prestige and outcompete competitors from other nations.
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