Claim checks

Yes, and it is not trivia. Individual identification from stripe patterns is the basis of essentially every published estimate of how many wild tigers there are.

Yes, in a specific and well-evidenced sense. Wild American crows learn a particular human face associated with being caught, remember it for years, and pass the association to birds that were never caught themselves. The "grudge" part is a human word for behaviour the experiments cannot see inside.

The behaviour is real, precise and measurably effective — injured ants are carried home and their wounds are treated with antimicrobial secretions that substantially cut mortality. What the coverage adds is intention. Nothing in the research shows any ant deciding to help, and the ants that are left behind are left because they stop signalling, not because anyone judged them beyond saving.

A fish can be trained to pick one human face out of dozens, which is a genuinely important result — it shows the task does not require the specialised brain structures usually invoked to explain it. But that is discriminating a photograph, not knowing who you are. No study has shown a fish recognising its owner.

Closer than you would expect, and not quite. A dolphin invents a whistle for itself as a calf and keeps it for life, others recognise the pattern with the voice stripped out, and dolphins copy each other’s whistles when separated. What has not been shown is one dolphin using another’s whistle to talk about it to a third.

Broadly yes, with two honest qualifications. Single genetically identical Armillaria individuals really do span many hectares — one mapped in Michigan covers about fifteen — and by area they outrank any animal or tree. But the mass and age figures are extrapolations from growth rate rather than measurements, and whether a spread-out genet counts as "one organism" is partly a matter of definition.

The mechanism is real and the phrasing is wrong in a way that matters. One hemisphere enters slow-wave sleep — an active, structured state — while the other stays awake enough to keep the animal swimming and surfacing. Nothing switches off. The arrangement exists because breathing in a dolphin is voluntary, so total unconsciousness would be fatal.

Yes, with three conditions that change what it means: only adult males, mainly in the breeding season, and it is used on other male platypuses rather than on prey or predators.

Close enough as shorthand — milk is secreted onto patches of skin rather than through teats — and it stops exactly where it gets interesting, which is what monotreme milk had to evolve to cope with as a result.

Dried into the tun state first, and shielded from sunlight, they survived ten days of vacuum well. Under unfiltered solar ultraviolet nearly all of them died — and an active tardigrade in vacuum dies at once.

Correct that tigers do not purr, and the reason usually given is the wrong one. It is the vocal folds rather than the bone. And tigers do make a warm greeting noise — the chuff — which anyone would call a purr if they had not been told otherwise.

On average yes — and tiger size varies more between tiger populations than the tiger–lion gap does. A large Amur or Bengal tiger outweighs a lion comfortably. A Sumatran tiger is smaller than essentially any lion.

Octopuses have a sleep stage with the behavioural and neural hallmarks of REM sleep, including rapid skin-colour changes and wake-like brain activity. Whether anything is experienced during it is unknown, and no available method could find out.

What was found is structure — the clicks vary along more dimensions than anyone had catalogued, and the variation tracks conversational context. No meaning has been demonstrated, and the paper does not claim any.

Fungi really do connect plant roots, and carbon really does move between trees below ground. The elaborated story — that networks are ubiquitous, that transfers matter to the recipient, and that mature trees preferentially feed their kin — was examined by two independent reviews in 2023 and found unsupported by the primary literature.

Real changes happened and wolves may have contributed. Whether they caused them is genuinely disputed: the specific prediction the theory makes was tested at landscape scale and did not hold, and the same period brought a severe drought, a bison irruption, recovering grizzlies and a large human elk hunt.

Predator satiation is a real hypothesis with real support, and it is not settled and involves no tree deciding anything. Where seed predators are resident, big crops do get more seed through; where they are mobile, it weakens. And a competing explanation has its own evidence: wind-pollinated trees flowering together get far more pollen onto stigmas.

Apes do learn hundreds of signs and use them deliberately. The claim that they combine them grammatically did not survive frame-by-frame analysis — and in the best-known gorilla case the records were never released, so it cannot be checked either way.

Two different claims. Habituation in Mimosa — the simplest form of learning, found in organisms with no nervous system — has support. Associative learning in pea plants, the result that made the case for something cognitive, failed to replicate.

The behaviour is real and repeatedly documented: elephants approach, touch and investigate dying and dead elephants, including unrelated ones, and return to remains. Whether they experience grief is not something any study so far could establish or rule out.

The memory is real and unusually long. The grudge is not something the experiments can see. Ravens recognise former companions by voice after up to three years, and their response differs depending on whether that individual was an ally or a rival — which is a statement about memory, not about intent to retaliate.

Honey keeps remarkably well, for reasons that are well understood: it is dry enough that most microbes cannot grow, mildly acidic, and generates hydrogen peroxide as it is diluted. But "never" overstates it — honey that takes up moisture will ferment — and it is not unique, since salt, sugar and dried grains keep on the same principle.

The experiments are real and the word is doing too much. Physarum finds the short path through a maze because tubes carrying more flow thicken and the rest are reabsorbed — no representation of the maze, no comparison, no choice. It genuinely does habituate, which is real learning of the simplest kind. Neither result needs, or supports, intelligence.

Around 88% of flowering plant species depend on animals — but the animals are tens of thousands of species of bee, fly, beetle, moth, butterfly, bird and bat. And the crops supplying most human calories are wind-pollinated: wheat, rice and maize need no animal at all. The finding underneath is more alarming, not less: the pollination that matters is largely done by wild insects nobody counts.

The reversal is real and the immortality is a translation error. Turritopsis medusae under stress can settle and turn back into polyps, escaping death by ageing. They remain entirely edible, and are eaten constantly. "Biologically immortal" describes senescence, not survival.

Some species usually re-pair; others usually do not, including both of the ones people picture. Most king penguin pairs do not re-form — and the reason is the breeding schedule rather than fickleness.

The abdomen really is replaced by a plug of spores while the animal flies around, and infected males really do give the female mating signal. What has never been shown is that the fungus controls anything, or that the detected drugs do anything.

The figure records *inactivity*, which includes resting, grooming, socialising and lying alert. Nobody has measured sleep in a wild lion, because that needs electrodes on one.

Crows really do gather and shout around a dead crow, and it has been tested with proper controls. What the experiment found was danger learning: the birds avoided the place afterwards and scolded the person who held the body for weeks. Nothing in the design could detect mourning.

The words are defensible and the impression is wrong. Nectar is carried in a crop — a storage pouch that is not the bee’s digestive stomach — and comes back up through the same route it went down. It is also chemically changed on the way: enzymes split the sugars, and the water content is driven from around 70% to under 20%. Regurgitated, yes. Digested and brought back up, no.

The comb really is close to a regular hexagonal array, and the efficiency is real. The mechanism is what is wrong. Bees do not measure angles: they work roughly circular cells in wax kept near 40°C, and the shared walls between neighbours relax into hexagonal junctions as the warm wax settles. The geometry emerges from physics acting on a material.

Everything in the mechanism is real and the word "calls" is not. A damaged plant emits volatile compounds, the blend differs depending on what is eating it, and parasitoid wasps orient towards it and find the caterpillars. Nobody is summoning anybody: injury has a chemical signature, and wasps that can smell it eat better than wasps that cannot.

A pollen grain contains sperm cells; it is not one. It is the male gametophyte — a complete, if tiny, organism of two or three cells with its own wall — which lands on a stigma and grows a tube down into the flower to deliver two sperm cells. The analogy hides the most interesting part, which is that the stigma inspects the grain and can refuse it.

A first-year bird inherits a direction and roughly how long to fly it — which is not the same as knowing where to go. Displace a juvenile a few hundred kilometres and it flies the same heading into the wrong country; displace an adult and it corrects. Knowing where you are is learned by making the journey. And the magnetic compass is not a GPS: it gives direction, not position.

No, and the distinction is what stops the word covering every resemblance in nature. Mimicry needs three parties: a model, a mimic, and a receiver whose behaviour changes because it is deceived. A stick insect is not being treated as a stick and acted on accordingly — it is not being detected at all, which is camouflage.

No individual makes the round trip. The autumn generation flies south and overwinters in Mexico, starts back north in spring and dies on the way; two or three further generations complete it. The butterflies arriving in Canada are the great-grandchildren of the ones that left, which makes the navigation harder to explain.

It happens, in a minority of species, and it is not what usually ends a spider mating. In most of the 52,000 known spiders the male leaves and may mate again. And in the best-known case that does fit the story — the redback — the male somersaults into the female’s fangs himself, which makes it his tactic rather than her ambush.

A very old female in the best-studied population may approach it; the average is nothing like it, and males average around thirty. One number cannot describe a species whose two sexes differ by twenty years and whose populations differ again.

It depends entirely which squirrel. Tree squirrels do not hibernate — they stay active all winter and the caches are what they live on. Ground squirrels are among the deepest hibernators known, and the arctic ground squirrel holds a body temperature below freezing. One word covering both makes the question unanswerable.

In most starfish an arm alone dies. Regrowing a whole animal from a fragment needs part of the central disc, and only a small number of species — Linckia most famously — manage it from an arm by itself. The reputation of the group comes from its exceptions.

No. Snakes have no eardrum and no external ear, which is not the same as no hearing. They detect airborne sound and are far more sensitive to low-frequency vibration through the ground — a hearing profile, not an absent sense.

Wrong end. It forms in the rectum, not the stomach, as a concretion around indigestible squid beaks — and it leaves the way that implies, or is released when a blocked whale dies.

Stressed plants do emit ultrasonic clicks — a few dozen an hour, at frequencies no human can hear, produced by water columns snapping under tension. Nothing indicates they are produced for a listener, and no listener has been identified.

It restores its mass, not its shape. Remove a lobe and the lobe does not return; the remaining tissue enlarges until the total is back to what it was, then stops — with remarkable precision.

The fur does fluoresce under an ultraviolet lamp — which is not glowing in the dark, and needs the lamp. Whether it means anything is entirely unknown, and it has since turned up in a lot of unrelated mammals.

An active tardigrade dies at around 37°C — roughly the temperature of a warm bath. Everything it is famous for belongs to the desiccated tun state, and even there the limits are finite and get worse with time.

Males hunt regularly and successfully — in cover, at night, favouring larger prey. The claim describes where and when researchers could see, not what lions do.

The pattern really is a property of the skin — it is drawn there in the embryo before the animal has any hair. The pigment you see is in the hair. Whether a shaved tiger looks striped is a third question, and we could not find anyone who has actually measured it.

They travel alone, which is what the word is doing. They also live inside a structured neighbourhood they maintain by continuous scent marking, and most tigresses settle next to their mothers — sometimes on ground their mother gives up for them.

No. The claim comes from a single small study published in a venue with an unclear review process, using subjective scoring, never independently replicated. There is no accepted evidence of mirror self-recognition in any insect.

No. Wild wolf packs are families — a breeding pair and their offspring — and the parents lead because they are the parents. The alpha model was derived from unrelated captive wolves confined together, and the researcher who popularised it has spent decades asking for it to be dropped.

No, and the claim fails on physics before it fails on biology. Shark olfaction is good but not extraordinary among fishes, and odour reaches a shark only as fast as the current carries it — a shark upstream of blood detects nothing at all, however close it is.

No. A lichen has no roots and no connection into the tree at all — it sits on the bark and absorbs water and minerals from rain and air. The correlation is real but the causation runs the other way: a tree with a thinning canopy lets more light through, and more light is what lichens want.

No, and the belief is dangerous in a specific way. The species responsible for most fatal poisonings is a plain greenish-white mushroom that reportedly tastes pleasant. The vivid red-and-white fly agaric of the illustrations is rarely fatal. Colour, smell, taste and whether animals eat it have no reliable relationship to toxicity.

They do, and the old objection measured the wrong thing. A denning black bear runs at roughly a quarter of its normal metabolic rate for months. Body temperature falls only a few degrees because a body that size cannot cool like a ground squirrel — not because the response is shallow.

No. About seven in ten orchids grow on other plants and take nothing from them: no root penetrates the host and no connection to its plumbing exists. They use a branch as a perch, collect water through a spongy root covering, and photosynthesise for a living. The word for that is epiphyte.

No. The paper exists and was published in a peer-reviewed journal, and it was rejected almost universally by the biologists who read it. Octopus genomes sit exactly where they should on the molluscan tree, sharing ancestry with squid, cuttlefish and snails. Being strange is not evidence of foreign origin.

No. Nothing is dislocated, because nothing was joined in the first place — the two halves of a snake's lower jaw are separate bones held together at the front by an elastic ligament, and they simply spread apart.

No snake hunts people, and none is known to pursue them. The experience is real: a frightened snake heading for cover will come straight at you if you are standing between it and the cover.

They have knees. The thigh bone is short and held roughly horizontally inside the body wall, so the knee sits under the feathers — and the backward-bending joint you can see is the ankle.

Two species out of roughly eighteen breed exclusively in Antarctica. The rest live around the Southern Hemisphere, and one breeds on the equator in the Galápagos. No penguin has ever met a polar bear.

Nobody has ever measured it. The multipliers descend from 1920s dynamometer trials on captive apes whose motivation could not be controlled — and the one rigorous measurement, at the level of muscle fibres in chimpanzees, found about 1.35 times.

No. Gorillas are a cousin lineage that has been evolving for exactly as long as we have, and chimpanzees are closer to us than gorillas are. We did not pass through a knuckle-walking stage either.

The decibel figure is real and is being quoted on the wrong scale. Underwater decibels use a different reference from the airborne ones people know; converting properly removes about 62 units. There is no documented case of anyone being harmed.

Plants detect damage quickly and specifically, and signal it through their own tissues. Detecting is not feeling: there are no pain receptors, no neurons and nothing that could constitute an experience.

The century figure traces to one report of a leg moving in a museum specimen, which was not revival. Tested against moss of documented age, survival runs to years and declines steeply.

Lions do not live in jungle. No male rules a pride — the females are the permanent members and the males are visitors who hold it for a few years. And lions lose carcasses to hyenas as well as taking them.

No. A white tiger is a Bengal tiger with two copies of one recessive change in a single pigment gene. It is not a species, not a subspecies, not a snow adaptation and not an albino — and no white tiger belongs to any wild conservation programme.