Stock Animal Facts

aka: Stock Animal Fact

"I know two things about the horse
And one of them is rather coarse."

— Naomi Royde-Smith

Whenever certain animals are mentioned, works (especially educational ones) will feel the urge to say a certain fact about them. Oftentimes it's intended to sound like something surprising or fascinating, which in general it would be if you didn't hear it every time that animal was mentioned in every work. With many more obscure species, their stock facts may be the only thing anyone (barring specialists) can ever say about them. Can overlap with Artistic License – Biology if it is clearly false. A victim of Science Marches On to the point that all of these facts should be taken with a grain of salt rather than believed outright.

Can overlap with Stock Animal Diet and Stock Animal Behavior.

Note: As this trope is based on its ubiquity, the only works that should be listed are aversions, subversions, lampshaded examples, in-universe examples, and other variants.

General Examples:

Mollusks

• The giant squid has eyes the size of dinner plates. No one has seen one alive. (Until 2004.)
• Snails leave behind a trail of slime that hardens and turns silver.
• If a bit of sand or a stone gets inside an oyster's shell, it'll produce nacre around it and produce a pearl. ^note Not entirely true. Pearls are usually stimulated by organic irritants such as parasites. Commercial oyster farmers do use inorganic irritants to grow pearls, however.
• Snails carry their "houses" on their backs. Only partially true— a snail can go into its shell, but its shell also contains organs, so calling it a house is rather inaccurate.
• Octopuses are the smartest invertebrates. (Debatable, depends on how one defines intelligence).

Annelids

• Earthworms can regenerate (many other invertebrates can, but earthworms are perhaps best-known for it). However, the common idea that cutting an earthworm in half will result in two earthworms is basically false; it's next to impossible for the half without a brain to grow a new one.

Arthropods

Insects

• Insects have six legs and are divided into three body segments.
• There are more insects (and arthropods in general) than any other type of animal on Earth. Around a quarter of all known animal species are beetles.
• Caterpillars become butterflies through metamorphosis. (Most other insects also go through metamorphosis, but it's always butterflies.)
• Insects can see colors that humans can't.
• Mayflies live only a few hours after attaining their adult form (the form in which they breathe and fly in the air). Their lifespan isn't that impressively short if you count their larval stage, where they swim around a lake much like mosquito larvae. Don't expect every source that talks about the matter to be clear on this qualification.
• Honeybees die after stinging. Somewhere, an Entomologist Is Crying if the same is said about bumblebees or wasps. Also, the death is because it can't extract itself from a sufficiently thick-skinned animal; they can still sting other bees without a problem.
• Most bees in a hive are sterile females.
• Bees communicate with each other with dance-like moves.
• A queen bee starts out as a regular larva but is fed royal jelly.
• Male bees or drones are stung to death after mating with the queen.
• Mosquitoes are the most dangerous animals on Earth by number of deaths caused. They're also the only animals on Earth that are more dangerous than humans.
  • And the reason they're dangerous is that they spread malaria. The fact that malaria is only spread by mosquitoes is a stock disease fact. What's less well-known is that malaria is only spread in certain countries.
• Some prehistoric dragonflies were the size of hawks.
• Cockroaches have been around "longer than dinosaurs". If you cut a cockroach's head off it can still survive for a few days. Cockroaches are the only animal capable of surviving all-out nuclear war (though lately, tardigrades have been gaining this reputation as well).
• Ants are really strong and are some of strongest animals for their size.
• Ant, bee, and wasp colonies have a collective mind. This one isn't, strictly speaking, true.
• Red ant colonies will sometimes invade black ant colonies.
• Army ants can reduce a corpse to bones in a few hours.
• The rhinoceros beetle is the strongest animal of its size.
• Fleas can jump really really high for their size.
• If this kind of insect was the size of a human, it'd be able to jump this high/lift this much/run this fast. The reason it can't happen is pretty much a stock fact too by now.
• Only female mosquitos bite. What's less well-known (but still relatively well-known) is that they have to do so in order to lay eggs.
• Female praying mantids actually bite off the male's head after mating.
• Contrary to popular belief, a wild beehive does not resemble a hornet nest.
• Bees make honey by regurgitating nectar.
• The zyzzyva (a South American weevil) is the last word in the dictionary.

Arachnids

• Spiders are not insects, they're arachnids because they have EIGHT LEGS (well, there's more to it than that, but very simplistic differences are often pointed out). Scorpions and ticks fall under this too.
• Spiderwebs are incredibly strong.
• Spiders don't eat their prey but suck its bodily fluids (not entirely true; they spit enzymes to turn the flesh into liquid and then suck that).
• Spiders die shortly after laying their eggs (or after guarding them until they hatch).
• Tarantulas are not actually all that dangerous.
• Scorpions glow in the dark under a blacklight.
• Black widow spiders are so-called because the more venomous female kills the male after mating (actually, this hardly ever happens in the wild, and even in captivity it doesn't always happen).

Crustaceans

• Crustacean blood (much like some other arthropods) is blue due to containing hemocyanin instead of hemoglobin.
• Crustaceans shed their exoskeletons regularly and grow larger with every moulting cycle— since most are underwater, the Square-Cube Law is much easier to mitigate.
• Crabs and lobsters are often eaten by boiling them while they're still alive.
• Hermit crabs have soft, curly tails and can use them to migrate from shell to shell as they grow larger.
• Fiddler crabs have a smaller claw for handling food and a larger claw for attracting mates.
• Larger species of crabs, including King crabs, can reach sizes of up to 4 meters (about 13 feet!) from the tip of one claw to another.
• Many crustaceans, including lobsters, don't show any physical signs of aging.
• Mantis shrimp have 12-16 different types of photoreceptors in their eyes and are much more sensitive to color as a result.
• Pistol shrimp can "shoot" predators and prey with a high pressure jet mechanism in their claws.
• Sea monkeys were "artificially created" (partly true, but they were created with artificial selection, not via Creating Life) and they breathe through their feet.

Echinoderms

• Sea stars feed by expelling their stomachs onto their food. This is actually only true for some sea star species.
• Sea cucumbers expel their own guts as a distraction if attacked.
• If a sea star is cut in half, then the two halves will become individual sea stars.

Fish

• Fish are "cold-blooded" (ectothermic) vertebrates with gills (although tuna have attained a sort of endothermy, while some lungfish have greatly reduced their gills).

Cartilaginous fish

• You're more likely to be killed by lightning/bees/cars/coconuts than to be killed by a shark.
  • And when sharks do kill humans, it's often by accident or because they've mistaken the human for prey.
• Sharks have been around "longer than dinosaurs". Technically true, but they haven't "remained unchanged" as many would have you think.
• Cladoselache was the first shark (debatable, depends on how you define a shark—see above).
• The whale shark is the largest living fish, but eats only plankton.
• The basking shark is the second largest.
• No one knows what the oddly shaped head of hammerhead sharks is used for (Not true, they use it as bludgeon to kill stingrays and to detect the electric pulses given off by bottom-dwelling fish).
• Tiger sharks can eat ANYTHING.
• Sharks frequently lose their teeth, which are always replaced by new ones growing in.
• Sharks must keep moving or they'll die (not true for wobbegongs, nurse sharks, whitetip reef sharks, etc).
• Unborn sand tiger sharks will sometimes eat their weaker siblings while still in the womb.
• Bull sharks can survive in freshwater.
• The megamouth shark was discovered in 1976 and has only been seen a few times since.

Bony fish

• Coelacanths are "living fossils". (They were thought long extinct until a live one was caught in 1938.)
• Lungfish breathe air.
• Salmon hatch, swim to the sea, return to their birthplace by swimming upriver while avoiding predators, spawn, then die (Not true for Atlantic salmon, which can lay eggs several years in a row).
• Flounders are so good at changing color they can blend into a chessboard.
• A number of people die from eating fugu every year.
• Electric eels are not really eels, but instead a species of knifefish.
• Male clownfish actually turn female if the dominant female dies. They live in sea anemones.
• Male seahorses fertilize and incubate the female's eggs in a special pouch and give birth. (They do not care for the young afterwards, however).
• A Siamese fighting fish will attack its own reflection.
• The growth of a goldfish is determined by the size of its environment.
• Male anglerfish are much smaller than the females. Their adult life consists of finding a female, latching on to her like a parasite, and essentially merging with her, becoming nothing more than a handy source of sperm.
• The candiru may swim up the urethra of a human urinating in the Amazon River, mistaking it for the gills of the fish whose blood it usually feeds on. (This actually only happened once.)
• The sailfish is one of the fastest animals in the world. (Not true.)

Amphibians

• Amphibians are "cold-blooded" (ectothermic), have slimy skin and can "live on both land and water". Not strictly true in the case of wholly aquatic amphibian species.

Salamanders and kin

• Axolotls never grow up. They do get bigger, but they retain a juvenile form (just picture an adult-sized baby).

Frogs and toads

• Tadpoles become frogs through metamorphosis. (Other amphibians also go through metamorphosis, but it's always frogs.) The only exception is the coqui and its relatives.
• Frogs have slimy skin and leap. Toads have bumpy skin and hop. (Not always true, and even if it were this is more or less like saying "round things are round." We call a species a frog or a toad based mainly on what whether it "looks like" a frog or a toad. Frogs and toads together are a clade; there are no clades which include all frogs but no toads, or all toads but no frogs.)
• Poison-dart frogs have really deadly poison. Their bright colors warn predators to stay away. South American native tribes use their poison for hunting.
• The cane toad is causing lots of problems in Australia.
• The Pacific tree frog is the only frog species that actually says "ribbit."
• The pipa toad incubates its young in its back.
• The paradoxical frog shrinks as it grows.
• Frogs and toads eat flies with their tongues (not true the way it's usually depicted, with a chameleon-type Overly-Long Tongue).

Reptiles

• Reptiles have dry scaly skin, are "cold-blooded" (more technically, ectothermic), and lay eggs on land. (Unless you're using cladistics, in which case birds are also a specialized clade of reptiles. Not to mention that many extinct animals traditionally thought to be "reptiles" were almost certainly to some degree warm-blooded.) Despite what the description of herpetology might tell you, amphibians are not reptiles, and vice versa. Reptiles are amniotes, along with mammals and birds.

Turtles, tortoises, and kin

• You can't take a turtle out of its shell (unless you intend to rip out its ribcage and a big chunk of its backbone).
• The leatherback turtle is the largest of all sea turtles. The Galapagos tortoise is the second-largest turtle, and the largest on land.
• Most baby sea turtles (hatched on the beach) are eaten by birds before they can reach the sea.
• A turtle flipped on its back cannot right itself and will eventually die. (Although this happens occasionally, most turtles are actually quite capable of righting themselves.)
• Tortoises can live well over one hundred years.
• Turtles are reptiles, not amphibians.

Snakes, lizards, and kin

• Various strange lizard defenses get a lot of attention (often the only attention these lizards will get):
  • Basilisk lizards can run on water.
  • Horned lizards spray blood from their eyes.
  • Many lizards can drop their tails as a distraction and regrow it later.
  • Blue-tongued skinks scare off predators using their blue tongues.
  • The frilled lizard spreads its frill to scare predators.
• Constrictor snakes and pythons aren't venomous, they suffocate their prey.
• The reticulated python and the anaconda are the longest and heaviest snake, respectively.
• Various legless lizards aren't actually snakes.
• The king cobra is the largest venomous snake. It is not a true cobra, by the way.
• Chameleons change color and can see in two different directions at once. They will turn white if they get startled.
• Geckos can climb vertical surfaces.
• This much venom from some kind of venomous snake is deadly enough to kill a huge number of people/mice.
• The Komodo dragon is the largest living lizard. It has deadly bacteria in its mouth it can use to kill prey. (It is now known that it relies more on shock and blood loss. Also, it may also have actual venom in its saliva, not just bacteria, although this is controversial.)
• The Gila monster and beaded lizard are the only venomous lizards. Again, Science Marches On (maybe).
• Non-venomous milk snakes and king snakes mimic venomous coral snakes. Red on yellow kills a fellow, red on black won't hurt Jack. (The part about mimicry is true, the part about the colors isn't. It may be true for certain regions with the caveat that you need to know whether you're in one of those regions or not.)
• Tuataras look like lizards, but they actually belong to a far more ancient assemblage. They have three eyes. They're only found in New Zealand.
• Mosasaurs were not dinosaurs. Unlike other famous Mesozoic reptiles, they were true lizards.
• Whiptail lizards are all female.
• The marine iguana is the only marine lizard (as long as you don't count sea snakes).
• Anacondas are really long.

Crocodilians

• Crocodiles have long narrow snouts and interlocking teeth, alligators have broader ones and overbites.
• Most crocodilians are able to take down HUGE prey with ease in the water. (The gharial is more or less stuck with fish.)
• A human can hold a crocodile's jaws shut without much effort, because the jaw muscles that open crocodile jaws are much weaker than those that close them.
• Crocodilians have four-chambered hearts like mammals and birds, and some of their ancestors were likely warm-blooded (or endothermic, if you prefer)
• Birds are their closest living relatives, as the two are the last remaining archosaur clades. It may sound strange, but they share more in common than with any other living reptile or mammal.
• The Florida Everglades is the only place where crocodiles and alligators coexist in the wild (untrue if you count caimans as alligators—the tropical rainforests of South America have both).
• Crocodilians appeared in the Age of Dinosaurs.

Dinosaurs

• Dinosaurs are reptiles with an erect stance and "couldn't swim or fly". (The latter is clearly false now that we know birds are dinosaurs, and even some traditionally non-bird dinosaurs are now known to have been capable of flying or swimming. The swimming thing is particularly ridiculous considering that most land animals can still swim, even if they aren't specialized for it or dislike getting wet.) "Dinosaur" means "terrible lizard" (though the intended meaning was actually "fearfully great" or "awe-inspiring reptile"). They can be divided into two major groups on the basis of their hip structure: saurischians ("lizard hips", including theropods and sauropodomorphs) and ornithischians ("bird hips", including ornithopods, pachycephalosaurs, ceratopsians, stegosaurs and ankylosaurs). Birds are saurischians, not ornithischians.^note Possibly a case of Science Marches On.
• Dinosaurs "ruled" the Earth for 150 million years before disappearing.
• We can't know what colors (prehistoric) dinosaurs were. This is no longer the case, at least for some well-preserved specimens.
• No one knows exactly how (non-bird) dinosaurs became extinct (in fact the K-Pg extinction is really one of the better understood mass extinctions). They were probably killed by an asteroid impact.
• There is a big debate about whether Tyrannosaurus is a scavenger or predator. This is actually an exaggeration as well as a false dichotomy, as only one recent researcher has endorsed the idea that Tyrannosaurus was an obligate scavenger and has now appeared to have abandoned this view^note if he ever actually held it at all, as he has claimed in interviews that he only proposed the idea to encourage critical thinking, while everyone else pretty much agrees that Tyrannosaurus would have been both a scavenger and a predator as the vast majority of land carnivores are today.
• Tyrannosaurus was the biggest carnivorous dinosaur. Now a victim of Science Marches On — the South American Giganotosaurus and North African Carcharodontosaurus and Spinosaurus may have been bigger in both length and mass.
• Oviraptor was thought to have been a specialist egg eater until it was found that the nest it was preserved on was its own, and that it was actually brooding its own nest. This discovery led to the popularity of the stock factoid that these dinosaurs were "good mothers", until the brooding specimens of Oviraptor were discovered to lack female-only medullary bone, indicating that they were in fact good fathers.
• Deinonychus may have hunted in packs. Pop culture Velociraptor, those inspired by Jurassic Park (1993) anyway, are Deinonychus in all but name.
• Sauropods/Stegosaurus had brains the size of a golf ball/walnut. They had a "second brain" in their hip region. (The second one isn't true.)
• Ankylosaurids could break the ankles of predators with their tail clubs.
• Sauropods were really really big. They were the largest dinosaurs, and the largest land animals ever.
• Giganotosaurus was larger than T. rex (debatable).
• Brontosaurus is a junior synonym of Apatosaurus. As of 2015, this is no longer true.
• Megalosaurus (1824), Iguanodon (1825), & Hylaeosaurus (1832) were the first Mesozoic dinosaurs validly named and used by Sir Richard Owen to define Dinosauria. Both were long used as wastebaskets for fragmentary bones that are actually very different and belong elsewhere.
• Spinosaurus, whose holotype was lost in World War II, had a huge sail on its back.
• Dilophosaurus (originally considered a species of Megalosaurus) had two crests but not a frill or venom.
• Stegosaurus used its plates for display or controlling its body temperature.
• Troodon was the smartest (non-bird) dinosaur. If it survived to the present, it would develop a humanoid form (ludicrously improbable).
• Microraptor had four wings.
• Allosaurus was an early relative of Tyrannosaurus (untrue beyond them both being avetheropods).
• Maiasaura cared for its young.
• Ceratosaurus had a horn on its nose and a row of scutes on its back.
• Micropachycephalosaurus had the longest name of any dinosaur.
• Cryolophosaurus, the first Mesozoic dinosaur named from Antarctica, was originally called "Elvisaurus" after the crest on its head.
• Deinocheirus is known only from a pair of giant arms. No one knows what the whole animal looked like (as of 2014, this is no longer true).
• Therizinosaurs were unusual herbivorous theropods. What’s usually unstated is that this isn’t actually unique for theropods since ornithomimosaurs and oviraptorosaurs mostly ate plants as well.
• Sauropods and hadrosaurs were once thought to be aquatic.
• Birds evolved from and, depending on your definition, may even be, dinosaurs.

Other reptiles

• Pterosaurs, plesiosaurs, and ichthyosaurs were not dinosaurs. Nor was Dimetrodon, which is more closely related to mammals.
• Ichthyosaurs had very large eyes. They gave live birth, eliminating the need to return to land to lay eggs. Older works will imply that this is unusual compared to other marine reptiles, but plesiosaurs & mosasaurs are now interpreted as live-bearers as well.
• When it was first described, Elasmosaurus's skull was placed at the end of its tail, starting the famous Bone Wars.
• The largest pterosaurs (like Quetzalcoatlus) were as large as a small airplane.
• Pteranodon had a large crest on its head. It was thought to have been a rudder to help steer in flight, but it is now believed to have been part of a mating display.
• Pterosaurs were the only reptiles capable of true flight (probably untrue depending on how many non-avian dinosaurs were capable of true flight).
• Tanystropheus had a ridiculously long neck.

Birds

• Birds have feathers, wings and beaks. Most can fly; all are "warm-blooded" (endothermic). In reality this applies more to modern birds, as many extinct birds lacked beaks and may have had a somewhat lower metabolism than modern birds. Also, many dinosaurs traditionally considered non-avian also had feathers and wings, and some may have even been able to fly.
• Male birds often have brighter plumage than females, the better to attract a mate. The female's drabber coloring allows her to blend in more with her environment, allowing her to better protect her young.
• The peregrine falcon is the fastest animal on Earth (in a dive).
• The spine-tailed swift is the fastest flying bird in level flight.
• The ostrich is the largest living bird and lays the largest eggs of any living animal. No, it doesn't stick its head in the sand to avoid danger, instead it crouches close to the ground or runs. It can run really fast, and can kill a lion with a kick. Its eyes are actually larger than its brain and are the largest of any land animal.
• Cassowaries can kill you with a kick. Which is possible but there have been only two (recorded) deaths from a Cassowary kick although non-fatal attacks are relatively common and certainly not pleasant experiences.
• Honeyguides guide honey badgers to honey. Which is not actually true (or at least, has not actually been recorded). They do guide humans to honey.
• Owls have really good hearing and can fly silently. They can turn their heads very far around. They regurgitate the fur, bones and other indigestible parts of their prey as "furballs" (often implied to be unique to owls, but this is false). They fly at night, whereas other birds of prey (traditionally called "falconiforms") hunt during the day (it's not that simple). They're one of the few animals that hunts skunks since they lack a sense of smell.
• Hummingbirds can fly backwards and hover in midair.
• The bee hummingbird is the smallest bird.
  • Their eggs, naturally, are very small too.
• Galapagos finches inspired Darwin's theory of evolution. (Actually, Galapagos mockingbirds had a bigger influence.)
• Vultures have bald heads because they eat messy food. This might not be entirely true.
• Vultures will circle a dying animal, biding their time before the banquet.
• American vultures are more closely related to storks than to other raptors (very likely false).
• The emu is the SECOND largest bird in the world (True if you're going by height, but if you're going by weight cassowaries are heavier).
• Elephant birds laid the biggest eggs ever.
• The marabou stork has bald head and neck and huge crop that make it one of the ugliest birds (subjective).
• The harpy eagle eats monkeys and sloths. Its feet are the size of a man's hand.
• The young hoatzin can use its wing claws to climb trees. The fact it retains wing claws is also often said to be unique among modern birds, but this is erroneous.
• Flamingos get their pink color from the microscopic crustaceans they eat. (This is actually the case for many brightly colored birds, though usually it's fruit or insects they eat instead.)
• Flamingos resemble both storks and geese, resulting in confusion surrounding their relationships (Science Marches On, as molecular analyses unanimously unite them with grebes).
• Parrots and crows are the smartest birds. They can mimic sounds (particularly human speech).
• Parrots are the longest-living bird.
• Quetzal was the sacred bird for the Aztecs.
• Archaeopteryx was the "first bird"... though this depends on its phylogenetic position and exactly what you call a bird.
• Pigeons mate for life, and males help females raise their young.
• Baby pigeons eat "pigeon milk" regurgitated by their parents.
• Prior to its extinction in 1914, the passenger pigeon was the most common bird in North America.
• Mandarin ducks will stop loving each other once their nest is built.
• A canary will never find a mate if it cannot sing. Only male canaries sing. (Actually female canaries sometimes sing, but that is extremely rare, and even if one does, her song will be much duller than a male's.)
• Male penguins court females by offering them pebbles (actually typical only for some kinds, expecially Adelie penguins).
• If frightened, a peacock will shed its distinctive tail feathers. (True, although the phenomenon of fright molt or schreckmauser is by no means unique to peacocks.)
• Shrikes impale their prey on thorns.
• The Egyptian plover feeds on scraps found in crocodilian mouths (very likely untrue).
• The pitohui is the only poisonous bird. A few other birds have since been discovered to be poisonous, and several more can sequester toxins in their flesh.
• Some penguins are gay, and gay penguins have been known to adopt orphaned chicks.
• The African grey parrot is the smartest type of parrot.
• Penguins, ostriches, and kiwis can't fly because their wings aren't built for it.
• Kookaburras sound as though they're laughing.
• Bustards are the heaviest flying birds.

Mammals

• Mammals have hair or fur, nurse their young with milk and are "warm-blooded" (endothermic). Most don't lay eggs. Not so with Mesozoic mammals, most of which were probably egg layers and may have had a slightly lower metabolism than modern mammals.
• In many species males will fight one another for the privilege of mating with a particular female.
• Male mammals tend to be more aggressive than female mammals unless her young are threatened.
• Mesozoic mammals were insignificant compared with dinosaurs (Science Marches On: Some mammals ate dinosaurs, and were much larger than the stereotype). The extinction of (non-bird) dinosaurs paved the way for mammals to "dominate".
• Mammals with binocular vision are carnivores and mammals with peripheral vision are herbivores. This is usually incorrectly implied to be true for all vertebrates.

Monotremes

• There are only one/two/three/five living egg-laying mammals. (In terms of species, five is the correct number, but many works will lump all the echidnas into the same category, or at most make a distinction between long-beaked echidnas and the short-beaked echidna.)
• The duck-billed platypus is one of the few living mammals that lay eggs. It also looks like a Mix-and-Match Critter. Males are venomous. They were originally thought to be a hoax.
• Echidnas are the only other living mammals that lay eggs.

Marsupials

• Marsupials are mammals with pouches (though some species have lost their pouches).
• Most modern maruspials are found only in Australia. (The fact that South America actually has a lot of other marsupials as well is almost never mentioned. Some works even claim that the Virginia opossum is the only non-Australian marsupial.)
• Marsupials are slower-moving, less intelligent and more "primitive" than placental mammals, which is why they eventually went extinct in most parts of the world.
• Opossums play dead. (Technically untrue if it's implied to be a deliberate action, as it's more of a reflex.) More specifically, it's the Virginia opossum that does this, but many works don't specify that. They are the only marsupials that live in North America.
• Opossums have prehensile tails. They're also idiots, as they have a small, simpler brain.
• Koalas are not bears. And they eat eucalyptus leaves to get moisture. Also, they only eat eucalyptus leaves. If they eat enough eucalyptus they will get stoned and fall out of trees; this is an improvement over what happens to any other animals, for whom eucalyptus sap is lethally toxic. Their appendixes are twice as long as their bodies. Parodied/subverted in an Olde English sketch, a Nature Mockumentary called "I Hate Nature". "Everyone knows that koalas eat eucalyptus leaves, but few people know why. The reason is that koalas are boring and they suck. No imagination."
• Wombats have backward-facing pouches so they don't get soiled while burrowing.
  • One semi-common animal fact about wombats is that their poop is cube-shaped.
• The yapok is the only semi-aquatic marsupial. It can close its pouch to stop water from entering.

Afrotheres

• Hyraxes are closely related to elephants and sea cows.
• Elephants are the largest land mammals. They're also the only quadrupeds that can't jump, excluding rhinos, hippos, sloths, tortoises… and Nairobi hosts an elephant jumping festival.
• African elephants have bigger ears than Indian elephants.
• Boat propellers pose a threat to manatee populations.
• The aardvark is the first animal in the dictionary.

Non-cetacean ungulates

• The pronghorn is the second fastest land animal, and has more endurance than the cheetah.
• The hippo is the most dangerous mammal in Africa. It secretes a fluid from its skin that looks like blood.
• No one knows what zebra stripes are for, but likely to be camouflage^note the most recent research indicates that their stripes repel a particularly dangerous type of fly. No two zebras have the exact same stripes.
• A camel can survive for days without drinking.
• A camel's hump is filled with fat, not water as was previously thought. The metabolism of fatty acids produces a large quantity of water, which is what allows a camel to survive for so long without dying from dehydration.
• Llamas were domesticated by the Inca, and are one of the few domesticated animals to come from the Americas.
• The giraffe is the tallest living animal.
• Pigs aren't actually dirty animals^note This depends on what you mean by "dirty"— they do go in mud (to keep cool), but they are very clean when it comes to their waste, preferring not to poop where they do other things, and are really quite intelligent.
• Rhinos have bad eyesight (probably not true).
• The white rhinoceros was named because the Dutch word for "wide" (referring to its broad lips) was confused with "white" (probably not true).
• The rhino’s horn is made of keratin, not bone.
• Pigs don't sweat.
• The okapi is the only living member of the Giraffid family aside from the giraffe itself, and much more closely resembles their shared ancestors. It is the last large terrestrial animal to be discovered by western science, having been identified in 1901 after years of searching.
• Even-toed ungulates have four-chambered stomachs. Cows are the most well-known for this, but it is also found in antelope, deer, and giraffids.
• Cows burp and fart an awful lot.

Cetaceans

• Whales are mammals, not fish.
• The blue whale is the largest animal ever, bigger than even the largest dinosaurs.
• The fin whale is the second largest animal ever.
• Whale vomit or ambergris is used to make perfume.
• Whales live in groups called pods.
• Whales will push a sick member of its pod to the surface so it can breathe.
• Whales communicate by "singing."
• Whales eat plankton (true only of baleen whales).
• Sperm whales prey on giant squid.
• Dolphins have been known to save drowning humans.
• Dolphins can kill sharks by butting them in the abdomen.
• "Dolphins have violent sex" is on its way to becoming this.
• The orca is the largest dolphin.
• Pakicetus was the first whale.
• Basilosaurus was originally interpreted as a reptile.

Carnivorans

• The cheetah is the fastest land animal. It can go as fast as a car on a highway.
• The honey badger is badass.
• The wolverine is badass and can chase off much larger predators.
• The tiger is the largest big cat, and one of the few which like water. It doesn't live in Africa. The jaguar is the other big cat that likes water. It also doesn't live in Africa.
• Mongooses can fight and kill venomous snakes (usually cobras). Some savvier works will also point out that snakes aren't that much of a mongoose's diet though.
• Hyenas aren't dogs, or pure scavengers. Their jaws can break bone. The females are dominant and have masculinized genitalia (It's actually more complicated than that— leadership in a hyena pack is passed down through the maternal lineage, but either male or female offspring can inherit their mother's rank). They sound as though they're laughing.
• Older books will claim that the giant panda is not a bear, but closer to raccoons. We now know it is indeed a bear. It only eats bamboo. (Technically, it'll sometimes eat meat as well.) It is also one of the few non-primate mammals that has opposable thumbs, or at least close enough to that.
• If you see a cougar, back away slowly^Why?The "back" part is so that you maintain eye contact and the cougar doesn't see you as a threat. The "slowly" part is so that its chasing instincts don't kick in. This applies to other big cats too. Now you know. and don't try to run. The cougar is known by many names (such as mountain lion and puma).
• The polar bear is the largest bear and non-pinniped carnivoran, and is also the most predatory bear. It actually has black skin and transparent fur. If you go near a female polar bear with her cub, she might kill you.
• Next to polar bears, grizzlies are the most dangerous.
• Bears are unlikely to attack humans unless they are mother bears accompanied by cubs.
• Bears hibernate during the winter months (although it's debated if this is true hibernation or not).
• Bears are apt to be irritable and dangerous if you run into in the spring right after they have woken up, without having eaten in months.
• Bears hate loud noises and can be scared off by shouting or a clanging bell.
• Lions are the only social felid. Males kill the cubs when they take over a pride.
• Female lions do most of the hunting.
• Domestic cats will tease and torment their prey before killing it. (This is probably just an instinctive response to movement).
• Raccoons are highly intelligent and will figure out any lock you put on your garbage bins. This has allowed them to thrive in urban environments
• Crabeater seals don't actually eat crabs.
• Binturongs, also known as bearcats, smell like fresh-buttered popcorn.
• Leopards drag kills up trees.
• House cats sleep sixteen hours a day and spend most of their waking time cleaning themselves.
• Cats never meow at each other unless they're kittens (not strictly true, though they do rely on body language a lot more than verbal communication).
• Never eat a polar bear's liver because it contains too much vitamin A for a human to metabolise.
• Tortoiseshell and calico cats are usually female, and the males are usually sterile. Likewise, ginger cats are usually male.
• Dogs don't actually see in black and white as was previously thought, but they do see fewer colours than humans. They have an acute sense of hearing and smell, were descended from wolves, and only the males lift a leg to pee. They're social animals, and if not properly trained will suffer from not knowing who the boss is.
• To run away from wolves, climb a tree.

Rodents and Lagomorphs (Hares and Rabbits)

• Rodents are the largest order of mammals.
• If rodents and rabbits don't have something to gnaw on, their teeth will grow indefinitely.
• Flying squirrels don't fly, they glide.
• Squirrels bury nuts throughout the fall so they will survive the winter. They often forget where the nuts are, however, and many trees get their start this way.
• Beavers cut down trees to build dams and lodges. The entrance to their lodges is located underwater. They warn conspecifics of danger by slapping their tail against the surface of the water.
• Porcupines don't shoot their quills. They aren't closely related to hedgehogs.
• North American porcupines have a craving for salt and are known to cause damage to human belongings due to this, as they go after the salt left by human sweat.
• Kangaroo rats don't need to drink water, they get it all from their food.
• Rats are highly intelligent and can learn to avoid virtually any trap.
• Rats have toxic urine (not true if the rat has no diseases).
• The capybara is the largest rodent.
• Rabbits are not really rodents.
• Hares are bigger than rabbits.
• Rabbits wreaked havoc on the Australian environment because they have no natural predators.

Primates

• Galagoes, lemurs and lorises are the "earliest" and most "primitive" primates.
• Lemurs are found only in Madagascar.
• Bush babies' enormous eyes allow them to see at night.
• Monkeys have tails, apes don't.
• Chimpanzees are the closest living relatives to humans. They know how to use tools.
• Chimpanzees are very aggressive as adults. Male chimps will slaughter their rivals' babies.
• Gorillas aren't actually all that aggressive.
• Howler monkeys are really, really loud.
• Orangutans are the largest arboreal animals
• Bonobos are the hippies of the primate world. They are cooperative, non-combative and very highly sexed.
• Apes can learn sign language (heavily debated).
• Man is a primate (and a mammal).
• Humans are the "most dangerous" animal (depends on your definition of "dangerous").
• While other animals use tools, humans are the species who's most dependent on them, and we might be the only species who makes tools.

Other mammals

• Bats are the only flying mammals and the second-largest order (after rodents). And they aren't blind, but most species do rely mostly on echolocation to find their way in the dark. Only a few species drink blood. They also don't fly into your hair. (In actuality, almost NO megabats aka fruit bats rely on echolocation, mostly because they are active during the day or mornings and evenings and use their well-developed eyesight instead of relying on sound.)
• Pangolins are the only mammals with scales.
• Male horses have big penises.

Exceptions, Subversions, Aversions, and Notable Examples in Media:

Web Original

• Essentially almost always averted at the Tetrapod Zoology blog, the one exception so far being basilisk lizards.

Western Animation

• In-universe example: in Phineas and Ferb, platypuses "don't do much".
  • They're actually semiaquatic egg-laying mammals of action.

Real Life

• That black widow fact is only half true. She will eat him if he sticks around to mooch off her web. Or, well, if they've been locked in a box for science.
  • Same for Praying Mantises, in the wild females do occasionally snack on the male if they are very hungry or stressed, but mostly they let him go.

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