These Australian mammals are bottom feeders. They scoop up insects and larvae, shellfish, and worms in their bill along with bits of gravel and mud from the bottom. All this material is stored in cheek pouches and, at the surface, mashed for consumption.
On land, platypuses move a bit more awkwardly. However, the webbing on their feet retracts to expose individual nails and allow the creatures to run. Platypuses use their nails and feet to construct dirt burrows at the water's edge.
Platypus reproduction is nearly unique. It is one of only two mammals the echidna is the other that lay eggs. Females seal themselves inside one of the burrow's chambers to lay their eggs. A mother typically produces one or two eggs and keeps them warm by holding them between her body and her tail.
The eggs hatch in about ten days, but platypus infants are the size of lima beans and totally helpless. Females nurse their young for three to four months until the babies can swim on their own.
All rights reserved. Common Name: Platypus. Scientific Name: Ornithorhynchus anatinus. Type: Mammals. Diet: Carnivore. Size: Head and body: 15 inches; tail: 5 inches. Weight: 3 pounds. Platypus have 5X and 5Y chromosomes organised in a ring that appears to have broken apart into pieces over the course of mammalian evolution. Comparing this chromosome information to humans, opossums, Tasmanian devils, chickens, and lizard genomes, the authors found the platypus's sex chromosomes have more in common with birds like chickens than mammals such as humans.
It's not too much of a surprise, therefore, that monotreme genomes contain most of the milk genes that other therian mammals possess. Casein genes help encode certain proteins in mammalian milk, but monotremes appear to have extra caseins with unknown functions.
That said, their milk is not unlike what comes from a cow, or even a lactating human. As such, the platypus is probably not as dependent on egg proteins as other bird and reptile species because it can later feed their young through the lactation glands on its skin. Its genome supports this. While birds and reptiles rely on three genes that encode for major egg proteins, the platypus appears to have lost the majority of these genes roughly million years ago.
Chickens today have all three egg protein genes, humans have none, and the platypus has only one fully functional copy left. The platypus is a weird in-between, and its genome is a sort of bridge to our own evolutionary past. The full genome has also revealed the loss of four genes associated with tooth development, which probably disappeared roughly million years ago. To eat, the platypus now uses a pair of horn-like plates to grind up its food. Severe skin ulcers caused by the amphibian fungal infection have been reported in Tasmanian Platypuses in particular.
The fungus can be fatal to the animal if it invades other tissues, particularly the lungs. Male Platypuses have a calcaneous, sharp spur about 12 millimetres long on each ankle.
The spur is connected via a long duct to a gland that produces venom, particularly in the breeding season. The venom can cause severe pain to humans, and although not lethal, the pain caused has been described as excruciating.
Swelling 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 temporary increased sensitivity to pain that persists for days or even months.
Therefore, if there is a need to handle a Platypus helping an injured animal for instance , it should always be picked up by the end half of the tail to avoid the spur in case it is a male. The fossil record for monotremes is poor in comparison to that of other groups of mammals, and until recently little was known about their evolutionary history.
Several fossil discoveries since the early s have shed some light on the origins of monotremes. We now know that monotremes were present in Australia during the Mesozoic Era, when Australia was still part of the supercontinent, Gondwana. Four species related to Platypus have been found in fossil deposits from Australia, including a complete skull of Obdurodon dicksoni and an opalised jaw fragment of Steropodon galmani.
The latter is million years old and represents one of Australia's oldest mammals. The only evidence that Platypus ancestors were once present outside Australia came in , when a million year old fossil tooth was found in Patagonia, in southern Argentina. Studies of these fossils indicate that the one remaining living species of Platypus is more specialised than its predecessors.
It is smaller, its functional teeth have been replaced by horny pads and other aspects of its anatomy appear simpler. It also appears to have a more restricted distribution, being confined to the river systems of eastern Australia. Although Platypus remains widespread and reasonably common, this trend towards increasing specialisation suggests that it may be moving out onto an evolutionary 'limb' and that its current status should not be taken for granted.
Grant, T. Fourth Edition. Menkhorst, P. A Field Guide to the Mammals of Australia. Oxford University Press, Melbourne. Third edition. Reed New Holland, Sydney. The Australian Museum respects and acknowledges the Gadigal people as the First Peoples and Traditional Custodians of the land and waterways on which the Museum stands. Image credit: gadigal yilimung shield made by Uncle Charles Chicka Madden. This website uses cookies to ensure you get the best experience on our website. Learn more. Similarly, King Island specimens are smaller than those found in Tasmania and Victoria.
Males are larger than females and can be over 60 cm long tip of the bill to tip of the tail. Typically, males are mm long, and females are mm long. The weight is g for males and g for females. Identification Platypus is well adapted for semi-aquatic lifestyle. Close Modal Dialog. Stay in the know Get our monthly emails for amazing animals, research insights and museum events.
Sign up today. A large tree branch is also pictured. Its bill appears to be a shiny, navy blue colour. The Platypus is on the bottom, left hand corner of the picture and is almost camouflaged by the brown tree branch. Habitat Platypuses occur in freshwater systems from tropical rainforest lowlands and plateaus of far northern Queensland to cold, high altitudes of Tasmania and the Australian Alps.
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