The platypus’s unusual biological features lend themselves to misinterpretation and exaggeration. In this section we identify some commonly encountered examples of fake platypus news and summarise the true scientific facts as they’re currently understood.
The platypus uses gravel to help mash up its food.
It’s true that the platypus sheds its set of true teeth (molars and premolars) around the time it first leaves the nesting burrow and starts to eat solid food, and also true that bits of mud or sand are sometimes found mixed with the remains of edible prey in the animal’s cheek pouches (used to store prey while the platypus swims underwater). However, there’s no reason to believe that this inedible material is anything other than an inconvenience. After losing its teeth, the platypus grinds up its prey using rough pads located at the back of its jaws. The grinding pads are made of keratin (the tough structural protein found in mammalian hair, claws, horns and hooves) and can reduce aquatic insects, freshwater shrimps and worms to a fine paste without any help needed from other abrasive agents (Grant 1989). See also Platypus Diet and Food Consumption.
LITERATURE CITED
Grant TR (1989) Ornithorhynchidae. Pp.436-450 in Fauna of Australia Volume 1B Mammalia (DW Walton and BJ Richardson, eds) Australian Government Publishing Service: Canberra.
The platypus doesn’t have a stomach.
The false news that the platypus lacks a stomach is based on a study that investigated the genes controlling platypus digestion and concluded that “the platypus lacks a functional stomach” (Ordoñez et al. 2008). The fact is that the platypus’s digestive tract does include a small expanded pouch-like section where one would normally expect a stomach to be located. The platypus’s stomach doesn’t secrete digestive acids or enzymes (Harrop and Hume 1980; Ordoñez et al. 2008), but does produce a mucus-rich fluid to assist nutrient absorption in the intestines (Krause 1971). Following on from the discussion of grinding pads above, it would seem that a platypus masticates food so thoroughly in its mouth that little additional processing is required before food reaches the intestines. Also, because a platypus consumes numerous small prey items over a period of many hours, its stomach doesn’t need to have a large holding capacity to accommodate infrequent large meals. See also Platypus Diet and Food Consumption.
LITERATURE CITED
Harrop CJF and Hume ID (1980) Digestive tract and digestive function in monotremes and nonmacropod marsupials. Pp. 63-77 in Comparative Physiology: Primitive Mammals (K Schmidt-Nielsen, L Bolis and CR Taylor, eds) Cambridge University Press: New York.
Krause WJ (1971) Brunner’s glands of the duckbilled platypus (Ornithorhynchus anatinus). American Journal of Anatomy 132, 147-165.
Ordoñez GR, LaDeana WH, Warren WC, Grützner F, López-Otín and Puenta XS (2008) Loss of genes implicated in gastric function during platypus evolution. Genome Biology 9, R81.
Platypus venom can kill a dog.
Platypus venom causes pain and swelling in affected human limbs, but isn’t considered to be life-threatening to people (see also Platypus Venom and Spurs). Similarly, though it’s often stated that platypus venom can kill a dog, there’s no convincing proof that this has ever occurred. It turns out that this generalisation is based on testimony from just one retired platypus hunter, who claimed that dogs belonging to him and his brother died after being spurred while retrieving a platypus shot to provide a pelt for the fur trade (Temple-Smith 1973). However, a different hunter reported that his dog survived being spurred on three different occasions, with the effects becoming less severe each time and no lasting ill effects occurring (Temple-Smith 1973). Two other early accounts of dogs recovering after being spurred have also been recorded (Special correspondence 1894).
In laboratory trials, rabbits and mice that have been injected with platypus venom showed only relatively mild effects and eventually recovered when venom was injected under the skin, but died when it was injected directly into a vein (Martin and Tidswell 1895; Temple-Smith 1973). We conclude that platypus venom could kill a dog in the unlikely event that a platypus happened to inject venom directly into a major blood vessel. Otherwise, though the dog would likely experience both pain and severe local swelling, it should recover completely from the experience.
LITERATURE CITED
Martin CJ and Tidwell I (1895) Observations on the femoral gland of Ornithorhynchus and its secretions; together with an experimental enquiry concering its supposed toxic action. Proceedings of the Linnean Society of New South Wales 9, 471-500.
Special correspondence (1894) Poisoned wounds produced by the duckmole (platypus). British Medical Journal 1 (1746), 1332.
Temple-Smith PD (1973) Seasonal breeding biology of the platypus, Ornithorhynchus anatinus (Shaw 1799), with special reference to the male. PhD Thesis: Australian National University, Canberra.
The platypus is one of only a few animals with biofluorescent fur.
In 2020, it was reported that platypus fur glows in lurid shades of purple, green and blue when illuminated by a strong source of ultraviolet light (Anich et al. 2020). This occurs because ultraviolet or UV light (which can’t be seen by the human eye) is absorbed by platypus fur and then re-emitted as visible longer-wavelength light. However, this is not an unusual attribute – biofluorescence is known to feature in plants, corals, jellyfish, insects, spiders, shrimp, more than 180 kinds of marine and freshwater fish, amphibians (including both frogs and salamanders), marine turtles and many different types of birds (Sparks et al. 2014; Gruber and Sparks 2015; Lamb and Davis 2020; Gershwin 2023). Biofluorescence has also been documented in more than 120 mammal species, most commonly in association with light-coloured fur or whiskers, bare skin (such as may occur around an animal’s eyes or inside a marsupial’s pouch), teeth (as is true for humans) and pigmented nails or claws (Travouillon et al. 2023). In the case of the platypus, the strongest biofluorescent response occurs in the paler fur of the belly, and debate continues whether this could have an adaptive function or is simply an accidental by-product of some compounds being present that happen to have fluorescent properties (Travouillon et al. 2023).
LITERATURE CITED
Anich PS, Anthony S, Carlson M, Gunnelson A, Kohler AM, Martin JG and Olson ER (2020) Biofluorescence in the platypus (Orithorhynchus anatinus). Mammalia 85, 179-181.
Gershwin L (2023) Update on fluorescent mammals and birds in Tasmania. Papers and Proceedings of the Royal Society of Tasmania 157, 79-97.
Gruber DF and Sparks JS (2015) First observation of fluorescence in marine turtles. American Museum Novitates 3845, 1-8.
Lamb JY and Davis MP (2020) Salamanders and other amphibians are aglow with biofluorescence. Scientific Reports 10, 2821.
Sparks JS, Schelly RC, Smith WL, Davis MP, Tchernov D, Pieribone VA and Gruber DF (2014) The covert world of fish biofluorescence: a phylogenetically widespread and phenotypically variable phenomenon. PLoS One 9, e83259.
Travouillon KJ, Cooper C, Bouzin JT, Umbrello LS and Lewis SW (2023) All-a-glow: spectral characteristics confirm widespread fluorescence for mammals. Royal Society Open Science 10, 230325.
Webbing between the platypus’s front claws retracts on land to expose its claws.
The mistaken idea that the platypus’s claws can be exposed or concealed like those of a cat presumably originated when someone misunderstood a written description of how a platypus walks. A platypus’s front foot features a broad expanse of skin (referred to as webbing) that extends well beyond its front claws in the water to form a highly efficient paddle (see also Platypus General Features and Fur Colour). The webbing folds neatly under the platypus’s palm when it walks, so its front claws (which are always exposed) are better placed to help grip the ground as the animal moves forward (Grant 1989).
LITERATURE CITED
Grant TR (1989) Ornithorhynchidae. Pp.436-450 in Fauna of Australia Volume 1B Mammalia (DW Walton and BJ Richardson, eds) Australian Government Publishing Service: Canberra.