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What the sources say

Duck-Billed PlatypusOrnithorhynchus anatinus

Every figure, record and mechanism on the Duck-Billed Platypus profile was written from a source, and this is the working table behind it: 58 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Animal Diversity Web, University of Michigan

Ornithorhynchus anatinus (duck-billed platypus). Animal Diversity Web, University of Michigan.

The page saysHigh
The source saysThey can harm humans with their venomous spurs if provokedNote: danger tier High = 'Dangerous when cornered or provoked' (facetMetadata.ts)
The page saysFreshwater rivers, streams, and lagoons across eastern Australia and Tasmania
The source saysThe geographic range of Ornithorhynchus anatinus is restricted to the wetter regions of eastern Australia and Tasmania ... Duck-billed platypuses inhabit rivers, lagoons, and streams
The page saysThe species lives in the wetter regions of eastern Australia and Tasmania, in rivers, lagoons and streams
The source saysThe geographic range of Ornithorhynchus anatinus is restricted to the wetter regions of eastern Australia and Tasmania ... Duck-billed platypuses inhabit rivers, lagoons, and streams
The page saysweightKg: 1.52
The source saysAverage mass 1.52 kgNote: task #708; ADW average adult mass. Light class (0.1 to 10 kg). In the curated matchup platypus vs lowland-streaked-tenrec.

Source
02

San Diego Zoo Wildlife Alliance

Platypus. San Diego Zoo Wildlife Alliance.

The page saysInsect larvae, freshwater shrimp, crayfish, and worms caught on underwater dives
The source saysThese underwater forays enable platypuses to feed on insect larvae, freshwater shrimp, freshwater crayfish called "yabbies"
The page saysPlatypuses and echidnas are the only living mammals that lay eggs, and together they are called monotremes
The source saysPlatypuses and echidnas are the only living mammals that lay eggs. They are called monotremes.
The page saysMales run 40 to 63 centimetres from bill to tail-tip and weigh up to 3 kilograms
The source saysLength from tip of bill to tip of tail: males 16 to 25 inches (40 to 63 centimeters) ... Weight: males: 1.8 to 6.6 pounds (0.8 to 3 kilograms)
The page saysfemales are smaller, at 37 to 55 centimetres and up to 1.7 kilograms
The source saysfemales 15 to 22 inches (37 to 55 centimeters) ... females: 1.3 to 3.7 pounds (0.6 to 1.7 kilograms)
The page saysPlatypuses typically live 12 to 15 years
The source saysLife span: 12 to 15 years on average
The page saysBy day it rests in a burrow dug along the bank, or under rock ledges, roots and debris
The source saysMale and female platypuses dig simple burrows along rivers and streams outside the breeding season. They can also make their home under rock ledges, roots, and debris, where they rest throughout the day.
The page saysIt is not fatal to people
The source says(It is not fatal to people, but is excruciating, and causes swelling.)
The page saysA spur can deliver enough venom to kill a medium-sized dog
The source saysIf the spur pierces skin, it can release enough venom to kill a medium-sized dog.
The page saysThere's more venom in the breeding season, which leads scientists to think males use it against rival males
The source saysThe venom is more plentiful during breeding season, leading scientists to believe that it's used to defend mates and resources from rival males.
The page saysThe bill carries 40,000 electroreceptors, which detect the electrical impulses living creatures make
The source saysabout 40,000 electroreceptors help them find the direction and distance of prey (its eyes and ears are closed while it’s underwater) by detecting electrical impulses generated by living creaturesNote: 40,000 also in manger-pettigrew-2008: 'There are 40,000 mucous gland electroreceptors found in the bill skin of the platypus'
The page saysDives usually last 30 to 60 seconds or so and go less than 5 metres down
The source saysthey may make repeated, short dives of 30 to 60 seconds or so ... they usually dive less than 16 feet (5 meters)
The page saysPrey goes into cheek pouches to be eaten at the surface: freshwater shrimp, crayfish called yabbies, worms and insect larvae
The source saysThese underwater forays enable platypuses to feed on insect larvae, freshwater shrimp, freshwater crayfish called "yabbies" (which it nuzzles out of the riverbed with its snout or catches while swimming), and worms. They use cheek pouches to stow bounty until reaching the surface, where they can eat.
The page saysHatchlings have molar-like milk teeth, but they're shed around the time the young leave the nesting burrow; adults grind food between pads made of keratin
The source saysdon’t have teeth, but instead grind their food between mouth pads made of keratin ... freshly hatched platypuses have molar-like “milk teeth," but these are shed around the time they leave the nesting burrow
The page saysOnly adult males have venom, which they deliver with spurs on their hind legs rather than by biting
The source saysAdult male platypuses have venomous spurs, an unusual characteristic among mammalsNote: 'only males' per ADW 'Males are generally larger than females, and have two venom glands attached to spurs on their hind legs'; not-a-bite from defensins-2008 'Rather than delivering venom through a bite, as do snakes and shrews, male platypuses have venomous spurs on each hind leg'
The page saysA stomach, yes; teeth, only as babies
The source saysdon’t have teeth, but instead grind their food between mouth pads made of keratin ... freshly hatched platypuses have molar-like “milk teeth,"
The page saysBaby platypuses start with molar-like teeth and lose them around when they first leave the burrow
The source saysfreshly hatched platypuses have molar-like “milk teeth," but these are shed around the time they leave the nesting burrow
The page saysFrom then on, pads made of keratin do the grinding
The source saysgrind their food between mouth pads made of keratin
The page saysAn egg-laying mammal
The source saysPlatypuses and echidnas are the only living mammals that lay eggs. They are called monotremes.Note: tagline (final pass)
The page saystags: insectivore
The source saysThese underwater forays enable platypuses to feed on insect larvaeNote: task #708; the tag's definition is 'Hunting insects, spiders, and grubs'; aquatic insect larvae are grubs. The tag feeds no battle stat.
The page sayshunts underwater with its eyes and ears shut
The source saysits eyes and ears are closed while itNote: vibe.reason, task #708
The page sayssteering by about 40,000 electroreceptors in its bill that pick up the electrical impulses of living prey
The source saysabout 40,000 electroreceptors help them find the direction and distance of preyNote: vibe.reason; SDZ continues 'by detecting electrical impulses generated by living creatures'; in the bill per manger-pettigrew-2008 '40,000 mucous gland electroreceptors found in the bill skin'

Source
03

Fenner, Williamson & Myers 1992

Fenner, Williamson & Myers (1992). Platypus envenomation - a painful learning experience. Medical Journal of Australia.

The page saysIntravenous narcotics could not control the pain from two spur wounds to one man's hand
The source saysA 57-year-old man was envenomated via two spur wounds to the right hand from each hind leg of a male platypus ... On admission to hospital, narcotics administered intravenously, both intermittently and by infusion, provided inadequate analgesia.
The page saysA nerve block at the wrist was dramatically effective
The source saysA right wrist block was dramatically effective.
The page saysThat's from the first detailed medical report of a platypus envenomation, published in 1992, about a 57-year-old man spurred by a male platypus
The source saysTo describe in detail for the first time, the clinical course and medical management of a significant human envenomation by the Australian platypus ... A 57-year-old man was envenomated via two spur woundsNote: 1992 is the paper's publication year (reference year)
The page saysthe venom produces "savage local pain and marked local swelling," and his hand did not work properly for three months
The source saysSignificant functional impairment of the hand persisted for three months, the cause of which is uncertain. Conclusions Male platypus venom remains largely unstudied. It produces savage local pain and marked local swelling, but no apparent tissue ischaemia.
The page saysYes, and painfully
The source saysPain was immediate, sustained, and devastating
The page saysNo antivenom exists
The source saysNo antivenom is available
The page saysThe 1992 report that first described a human case in detail concluded that blocking the nerves to the wounded area appears to be the only pain relief that works, and its patient spent six days in hospital
The source saysTo describe in detail for the first time, the clinical course and medical management of a significant human envenomation ... The patient spent six days in hospital ... in its absence the only effective analgesia appears to be regional nerve blockade, when the envenomation site and available skills permit.Note: 1992 is the reference year

Source
04

Whittington et al. 2008

Whittington et al. (2008). Defensins and the convergent evolution of platypus and reptile venom genes. Genome Research.

The page saysA genetics paper on the platypus's venom opens by noting that when the species was first found, it "was thought to be a taxidermist's hoax, as it has a blend of mammalian and reptilian features."
The source saysWhen the platypus (Ornithorhynchus anatinus) was first discovered, it was thought to be a taxidermist's hoax, as it has a blend of mammalian and reptilian features.
The page saysMale platypuses deliver venom through spurs on their hind legs, not through a bite
The source saysRather than delivering venom through a bite, as do snakes and shrews, male platypuses have venomous spurs on each hind leg.
The page saysIts major components come from a repurposed antimicrobial gene: three venom genes arose when copies of a gene family called beta-defensins duplicated and changed function
The source saysWhile searching the platypus genome for the sequences of antimicrobial defensin genes, we identified three Ornithorhynchus venom defensin-like peptide (OvDLP) genes, which produce the major components of platypus venom. We show that gene duplication and subsequent functional diversification of beta-defensins gave rise to these platypus OvDLPs.
The page saysSome snakes and lizards make similar venom molecules, but theirs evolved separately, so the trick has evolved more than once
The source sayssome species of snakes and lizards also produce venoms containing similar molecules called crotamines and crotamine-like peptides ... Here we show that several venom components have evolved separately in the platypus and reptiles. Convergent evolution has repeatedly selected genes coding for proteins containing specific structural motifs as templates for venom molecules.
The page sayswith venomous spurs
The source saysRather than delivering venom through a bite, as do snakes and shrews, male platypuses have venomous spurs on each hind leg.Note: tagline (final pass)
The page saysonce thought to be a taxidermist's hoax
The source saysit was thought to be a taxidermist's hoaxNote: tagline (final pass)

Source
05

Nature 2008

Genome analysis of the platypus reveals unique signatures of evolution.

The page saysThe paper reporting its genome sums up the mix: platypus females lactate, yet lay eggs, and males are equipped with venom similar to that of reptiles
The source saysThis monotreme exhibits a fascinating combination of reptilian and mammalian characters. For example, platypuses have a coat of fur adapted to an aquatic lifestyle; platypus females lactate, yet lay eggs; and males are equipped with venom similar to that of reptiles
The page saysWhen a platypus forages underwater, its eyes, ears and nostrils are closed, and an electrical sense in its bill helps it find prey
The source saysWith its eyes, ears and nostrils closed while foraging underwater, it uses an electro-sensory system in the bill to help locate aquatic invertebrates and other prey
The page saysWith their bills
The source saysit uses an electro-sensory system in the bill to help locate aquatic invertebrates and other prey
The page saysan electric sense in its bill
The source saysWith its eyes, ears and nostrils closed while foraging underwater, it uses an electro-sensory system in the bill to help locate aquatic invertebrates and other preyNote: tagline (final pass)

Source
06

Manger & Pettigrew 2008

Manger & Pettigrew (2008). Ultrastructure, Number, Distribution and Innervation of Electroreceptors and Mechanoreceptors in the Bill Skin of the Platypus, Ornithorhynchus anatinus (Part 1 of 2). Brain, Behavior and Evolution.

The page saysElectroreceptive bill with 40,000 electroreceptors, venomous hind-leg spurs, and cyan-green UV biofluorescence
The source saysThere are 40,000 mucous gland electroreceptors found in the bill skin of the platypusNote: venomous hind-leg spurs covered by the defensins-2008 claim; biofluorescence covered by anich-2020 claim
The page saysplus 46,500 touch receptors
The source saysA push-rod mechanoreceptor, similar in morphology to Eimer's organ of the mole, and bill-tip organs in birds, was also found in the bill skin ... Although less numerous than the mechanoreceptors (46,500 mechanoreceptors compared with 13,500 sensory serous glands)
The page saysIn 2008, researchers who mapped the bill called the platypus "presently the only mammal demonstrated to use electroreception to obtain food."
The source saysThe platypus is presently the only mammal demonstrated to use electroreception to obtain food.Note: 2008 is the paper's year; the sentence is dated because 'presently' is a 2008 state
The page saysUnderwater, a platypus keeps its eyes, ears and nostrils closed and locates prey with sensors in its bill: about 40,000 that detect electric fields and 46,500 that respond to touch
The source saysThere are 40,000 mucous gland electroreceptors found in the bill skin of the platypus ... Although less numerous than the mechanoreceptors (46,500 mechanoreceptors compared with 13,500 sensory serous glands)Note: eyes/ears/nostrils closed from genome-2008: 'With its eyes, ears and nostrils closed while foraging underwater'
The page saysA 2008 study of the bill's anatomy called the platypus the only mammal then shown to find food by electroreception
The source saysThe platypus is presently the only mammal demonstrated to use electroreception to obtain food. ... This paper presents an anatomical study of the basis of electroreception in the platypus.Note: 2008 is the reference year

Source
07

Ordoñez et al. 2008

Ordoñez et al. (2008). Loss of genes implicated in gastric function during platypus evolution. Genome Biology.

The page saysA 2008 genetic study found that platypuses have lost the main genes for making and using gastric juice, including those for pepsin and the stomach's acid pump
The source saysthe main genes implicated in the formation and activity of gastric juice have been lost in platypus. These include the aspartyl proteases pepsinogen A and pepsinogens B/C, the hydrochloric acid secretion stimulatory hormone gastrin, and the alpha subunit of the gastric H+/K+-ATPase.Note: acid pump = gastric H+/K+-ATPase; 2008 is the reference year
The page saysLosing the genes for the stomach's acid pump explains at least part of that, according to a 2008 genome study
The source saysconfirms the absence of a functional H + /K + -ATPase in this vertebrate and provides at least part of the explanation for the lack of acid secretion in the platypus stomachNote: 2008 is the reference year

Source
08

Nicol 2025

Nicol (2025). Does the platypus have a stomach? The perils of popular science. Australian Zoologist.

The page saysThat's not the same as having no stomach, a claim a 2025 review uses as an example of how "science misinformation can be propagated."
The source saysshow how the absence of acid secretion has been confused with absence of a stomach. The misunderstanding and misrepresentation of platypus anatomy and physiology provides an interesting example of how science misinformation can be propagated.Note: 2025 is the reference year
The page saysPlatypuses "do have stomachs," the review says, just non-secretory ones, unlike those of all other mammals
The source saysplatypuses and echidnas do have stomachs, although they differ from the stomachs of all other mammals by being non-secretory
The page saysA 2025 review of the widespread claim that the platypus has no stomach found it wrong: platypuses do have a stomach, but it doesn't secrete digestive juices
The source saysIf you search the internet for platypus stomach you will find countless websites stating that the platypus has no stomach ... But platypuses and echidnas do have stomachs, although they differ from the stomachs of all other mammals by being non-secretory.Note: 2025 is the reference year

Source
09

Anich et al. 2020

Anich et al. (2020). Biofluorescence in the platypus (Ornithorhynchus anatinus). Mammalia.

The page saysUnder ultraviolet light, the brown fur of three museum specimens glowed green or cyan, the first biofluorescence reported in any monotreme
The source saysWe examined three specimens of the platypus ( Ornithorhynchus anatinus ) from Tasmania and New South Wales, Australia, housed in the Field Museum of Natural History (Chicago, Illinois, USA) and the University of Nebraska State Museum (Lincoln, Nebraska, USA) under visible light and ultraviolet (UV) light. The pelage of the animals appeared uniformly brown under visible light and green or cyan under UV light, due to fluoresced wavelengths that peaked around 500 nm. Our observations are the first report of biofluorescence in a monotreme mammal.
The page saysTheir fur biofluoresces
The source saysThe pelage of the animals appeared uniformly brown under visible light and green or cyan under UV light
The page saysIn a 2020 study, researchers shone UV light on three museum specimens
The source saysWe examined three specimens of the platypus ( Ornithorhynchus anatinus ) from Tasmania and New South Wales, Australia, housed in the Field Museum of Natural History (Chicago, Illinois, USA) and the University of Nebraska State Museum (Lincoln, Nebraska, USA) under visible light and ultraviolet (UV) light.Note: 2020 is the reference year
The page saysFur that looked plain brown in normal light showed green or cyan, from emitted light peaking around 500 nanometres
The source saysThe pelage of the animals appeared uniformly brown under visible light and green or cyan under UV light, due to fluoresced wavelengths that peaked around 500 nm.
The page saysIt was the first report of biofluorescence in any monotreme
The source saysOur observations are the first report of biofluorescence in a monotreme mammal.

Source
10

Woinarski & Burbidge 2016

Woinarski & Burbidge (2016). Ornithorhynchus anatinus. The IUCN Red List of Threatened Species 2016: e.T40488A21964009.

The page saysNear Threatened
The source saysIUCN Red List category: Near Threatened (NT).Note: assessment category read through GBIF's copy of the Red List per docs/fact-check.md

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.