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What the sources say

Box JellyfishChironex fleckeri

Every figure, record and mechanism on the Box Jellyfish profile was written from a source, and this is the working table behind it: 47 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

Chironex fleckeri (box jellyfish). Animal Diversity Web, University of Michigan.

The page saysA Transparent Predator with Up to Sixty Tentacles
The source saysThere can be as many as 15 tentacles hanging from each of the four pedalia for a total of up to 60 tentacles per jellyfish.Note: covers the heading's spelled-out tentacle count
The page saysIts box-shaped bell usually measures 16 to 24 cm across, though some grow to 35 cm
The source saysThe bell is transparent and is usually between 16 and 24 cm, though some reach a diameter of 35 cm.
The page saysup to 60 tentacles hang from its four corners, trailing as far as 3 metres (10 feet)
The source saysThere can be as many as 15 tentacles hanging from each of the four pedalia for a total of up to 60 tentacles per jellyfish. Each of the tentacles ... can grow up 3 m in length.Note: 10 feet, converted from 3 m (ADW's own conversion: 9.84 ft)
The page saysA full-grown adult can weigh up to 2 kilograms
The source saysRange mass 2 (high) kg
The page saysUnlike the drifting jellyfish most people picture, box jellyfish are active swimmers
The source saysMost notably, box jellyfish can actively swim, whereas most species of jellyfish float wherever the current takes them with no control over their direction.
The page saysThey can move at up to 4 knots, though by day they typically travel at 1 knot or less
The source saysbox jelly have the ability to move up to 4 knots, during the day they typically travel at 1 knot or less
The page saysAdults feed mainly on small fish and prawns
The source saysAdult box jellyfish tend to feed in shallow waters, mainly on small fish and prawns.
The page saysuntil they're fully grown they feed primarily on shrimp
The source saysUntil they are fully grown, box jellyfish feed primarily on shrimp, most commonly Acetes australis.
The page saysEach spring, box jellyfish gather in rivers to spawn
The source saysEvery spring, box jellyfish gather to spawn in rivers and similar bodies of water.
The page saysthen die shortly after
The source saysShortly after spawning, box jellyfish die.
The page saysTwenty-Four Eyes and No Brain
The source saysBox jellyfish contain sensory organs including 24 eyes, but they do not have a brain.Note: covers the heading's spelled-out eye count
The page says24 eyes
The source saysBox jellyfish contain sensory organs including 24 eyes, but they do not have a brain.Note: short claim that also covers the tagline and stats.superpower numeral
The page saysA box jellyfish has no brain, yet it carries 24 eyes
The source saysBox jellyfish contain sensory organs including 24 eyes, but they do not have a brain.
The page saysphotoreceptors that tell light from dark, it's drawn toward light and it tends to avoid darker shapes
The source saysBox jellyfish do have eyes, which have photoreceptors. Photoreceptors give box jellyfish the ability to detect light from dark ... Box jellyfish, however, are attracted to light and tend to avoid darker shapes.Note: FAQ 2
The page saysIts eyes' photoreceptors tell light from dark, it's drawn toward light and it tends to avoid darker shapes
The source saysBox jellyfish do have eyes, which have photoreceptors. Photoreceptors give box jellyfish the ability to detect light from dark ... Box jellyfish, however, are attracted to light and tend to avoid darker shapes.
The page saysIts only known predator is the green turtle, whose skin is too thick for the venom to penetrate
The source saysThe only known predator of box jellyfish are green turtles ... Venom does not penetrate the thick skin of green turtles, which are thus unaffected by the stings of box jellyfish.
The page saysEach tentacle carries millions of microscopic stinging cells
The source saysEach tentacle contains millions of nematocysts, which are microscopic hooks where venom is held and delivered.
The page saysit had accounted for more than 60 recorded deaths, most of them children and young adults
The source sayshas accounted for more than 60 deaths in the last 100 years. Most fatalities are documented in children and young adults.Note: ADW's count, framed there as 'in the last 100 years'
The page saysPrawns and small fish, with young feeding mostly on shrimp
The source saysAdult box jellyfish tend to feed in shallow waters, mainly on small fish and prawns. ... Until they are fully grown, box jellyfish feed primarily on shrimpNote: stats.diet, corrected during this rewrite (dropped the unsupported "crabs" and "marine larvae")
The page saysChironex fleckeri, the box jellyfish, is nearly invisible in the water off Northern Australia and Southeast Asia, where it hunts through shallow coastal waters, estuaries and mangrove channels.
The source saysChironex fleckeri, also known as box jellyfish, lives in and around the waters of Australia and Southeast Asia.Note: range clause; the habitat detail (shallow waters, mangrove channels) is the same ADW passage cited for stats.habitat
The page saysnearly invisible in the water
The source saysThe bell is transparent and is usually between 16 and 24 cmNote: also covers the tagline's 'translucent' and vibe.reason's 'nearly invisible in clear water'
The page saysNot Evaluated
The source saysIUCN Red List No special statusNote: stats.conservationStatus; GBIF's copy of the IUCN Red List returns no assessment for Chironex fleckeri (checked 2026-09-18), so the species is unassessed
The page saysAs of 2012
The source saysLast updated: 2012-02-26Note: the date of the ADW account the death count comes from (Schmidt, T. 2012), so the count is 'more than 60' as of 2012 rather than a rolling century
The page saysweightKg: 2
The source saysRange mass 2 (high) kgNote: task #613; battleStats.weightKg. ADW states only an upper figure. Light class runs 0.1 to 10 kg, so a 16 to 24 cm bell with 3 m tentacles is Light at any plausible adult mass

Source
02

Brinkman et al. 2015

Brinkman et al. (2015). Transcriptome and venom proteome of the box jellyfish Chironex fleckeri. BMC Genomics.

The page saysresearchers who sequenced its venom call it the largest and most dangerous cubozoan jellyfish to humans
The source saysThe box jellyfish, Chironex fleckeri, is the largest and most dangerous cubozoan jellyfish to humans.
The page saysTriggered, each one explosively releases a harpoon-like tubule that injects venom into its victim
The source saysWhen triggered to discharge, each nematocyst explosively releases a harpoon-like tubule that injects a toxic cocktail of venom components into the victim or prey.

Source
03

Yanagihara & Shohet 2012

Yanagihara & Shohet (2012). Cubozoan Venom-Induced Cardiovascular Collapse Is Caused by Hyperkalemia and Prevented by Zinc Gluconate in Mice. PLoS ONE.

The page saysA venom protein punches pores about 12 nanometres wide clean through human red blood cells
The source saysWell-formed pores were observed that appeared to fully perforate the RBC membranes with an inner diameter of approximately 12 nm.Note: electron microscopy of human red blood cells exposed to purified C. fleckeri venom porin
The page sayspotassium pours out through the holes
The source saysMarked potassium release occurred within 5 min and hemolysis within 20 min in human red blood cells (RBC) exposed to venom or purified venom porin.
The page saysthat potassium surge began within 5 minutes of exposure, with the cells breaking down by 20 minutes
The source saysMarked potassium release occurred within 5 min and hemolysis within 20 min in human red blood cells (RBC) exposed to venom or purified venom porin.
The page saysresearchers found this hyperkalemia, a dangerous spike in blood potassium, to be the likely trigger for the cardiovascular collapse that follows a severe sting
The source saysThese findings suggest that hyperkalemia is the critical event following Chironex fleckeri envenomation
The page saysIts venom drives potassium out of red blood cells
The source saysMarked potassium release occurred within 5 min and hemolysis within 20 min in human red blood cells (RBC) exposed to venom or purified venom porin.Note: FAQ 1
The page saysThe venom's pore-forming toxin punches roughly 12-nanometre holes through red blood cells
The source saysElectron microscopy revealed abundant ~12-nm transmembrane pores in RBC exposed to purified venom porins.Note: FAQ 3
The page saysresearchers say, through muscle-cell membranes too
The source saysThe venom has also been recognized to create pores in myocytic membranesNote: FAQ 3; the paper's word is 'myocytic', so 'heart-muscle' was narrowed to 'muscle-cell'
The page saysPotassium then leaks rapidly into the bloodstream, a condition called hyperkalemia, which researchers found to be the likely trigger for the cardiovascular collapse that follows a severe sting
The source saysThese findings suggest that hyperkalemia is the critical event following Chironex fleckeri envenomationNote: FAQ 3
The page sayspore-forming venom that drives potassium out of human blood cells within 5 minutes
The source saysMarked potassium release occurred within 5 min and hemolysis within 20 min in human red blood cells (RBC) exposed to venom or purified venom porin.Note: stats.superpower
The page sayscarrying a pore-forming venom that can cause cardiovascular collapse and death
The source saysChironex fleckeri (Australian box jellyfish) stings can cause acute cardiovascular collapse and death.Note: vibe.reason, corrected during this rewrite (was "bio-electrical punch", not this animal's mechanism)
The page saysresearchers found this hyperkalemia, a dangerous spike in blood potassium, to be the likely trigger for the cardiovascular collapse that follows a severe sting
The source saysThese findings suggest that hyperkalemia is the critical event following Chironex fleckeri envenomationNote: FAQ 1

Source
04

Gordon & Seymour 2012

Gordon & Seymour (2012). Growth, Development and Temporal Variation in the Onset of Six Chironex fleckeri Medusae Seasons: A Contribution to Understanding Jellyfish Ecology. PLoS ONE.

The page saysat the growth rates measured off Queensland, wild medusae, the free-swimming adult form, reach sexual maturity at about 45 to 50 days old, and the oldest one researchers aged was roughly 78 days
The source saysAt the rapid rate of growth quantified here, medusae would become sexually mature after ~45-50 d ... Given that the oldest medusa was ~78 dNote: statolith growth-ring ageing of wild medusae, Weipa, north Queensland; the maturity figure is the paper's projection from its measured growth rate
The page saysclustered into four eye-bearing sensory structures called
The source saysthe statoliths contained within the statocysts of cubomedusae rhopalia (eye bearing sensory structures) ... Each of the four rhopalial nichesNote: covers the body sentence and FAQ 2; the paper's IPD definition puts the rhopalia between the pedalia, so the earlier 'hanging from the bell's corners' was cut
The page saysCoastal shallow waters, estuaries
The source saysA total of 484 medusae were collected from seven sites at Weipa ... Weipa sites were classified as coastal or estuarine sites.Note: stats.habitat and the body's 'estuaries': ADW names rivers and mangrove channels, this paper is where medusae are recorded from estuarine sites

Source
05

DeLoughery 2022

DeLoughery (2022). There's something in the water: an overview of jellyfish, their stings, and treatment. International Maritime Health.

The page saysChironex fleckeri is described in medical literature as the most lethal jellyfish worldwide
The source saysThe most lethal jellyfish worldwide, Chironex fleckeri , or the Australian box jellyfish, is a CubozoanNote: covers the body sentence and FAQ 1
The page saysdeath can occur in as little as 2 to 10 minutes
The source saysdeath from envenomation can occur in as little as 2-10 minutesNote: in the review's Chironex fleckeri paragraph; covers the body sentence and FAQ 1
The page saysestuaries, and mangroves of Northern Australia and Southeast Asia
The source saysranging from Northern Australia to Southeast AsiaNote: stats.habitat range clause; the habitat types are the ADW passage cited on the neighbouring claim
The page saysoff Northern Australia and Southeast Asia
The source saysranging from Northern Australia to Southeast Asia
The page saysA Sting That Can Stop a Heart in Minutes
The source saysDeath can occur due to respiratory and cardiac arrest from the venom ... death from envenomation can occur in as little as 2-10 minutesNote: covers the heading; the body and FAQ 1 carry the figure itself
The page saysvenom that can kill a person in minutes
The source saysdeath from envenomation can occur in as little as 2-10 minutesNote: tagline

Source
06

Hamner, Jones & Hamner 1995

Hamner, Jones & Hamner (1995). Swimming, feeding, circulation and vision in the Australian box jellyfish, Chironex fleckeri (Cnidaria:Cubozoa). Marine and Freshwater Research.

The page saysin the laboratory medusae swam away from dark objects
The source saysIn the laboratory, medusae visually reacted to dark objects by swimming away from them.Note: the paper's aquarium animals were juvenile to subadult medusae

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.