Go on. Look inside.

Some shopping carts have a hidden brake in one wheel.

In the forests of Madagascar, one moth feeds on something stranger than nectar.

Almost everyone has wondered what happens if an elevator's cable snaps.

Child-resistant medicine caps hide a two-part lock that only opens when you push down and turn at the same time.

Some tick bites can leave something behind: an immune reaction to alpha-gal, a sugar found in beef, pork and lamb.

A coin battery has no sharp edges, but if it gets stuck in the esophagus, wet tissue completes its circuit.

The shrike looks like a harmless little grey songbird, but its feet are too weak to hold prey.

The tongue-eating louse is a tiny ocean parasite that slips into a fish through its gills and clamps onto the tongue.

Pull a seatbelt slowly and it glides out, but yank it and it locks right away.

Every popcorn kernel is a tiny sealed pressure cooker.

When a giant hornet scout finds a Japanese honeybee nest, hundreds of bees pile onto it and form a tight ball.

An onion keeps two chemicals stored apart inside its cells.

Cats can't taste sweetness.

That tiny hole in your plane window is there on purpose.

The Fitzroy River turtle in Australia pumps water in and out of its rear end.

Inside an ordinary door lock, five split pins decide which key is allowed to turn.

When a giraffe drinks, its head drops from about two metres above its heart to below it.

Hippos sometimes look like they are covered in blood, but the red stuff is not blood and not sweat.

Chocolate contains theobromine, a chemical closely related to caffeine.

Your microwave door is full of holes, so why doesn't it cook you?

A cat's tongue is covered in hundreds of stiff, backward-curving spines made of keratin, and each one has a hollow scoop at the tip.

Fulmar chicks spend a lot of time alone on cliff ledges while their parents feed at sea.

Glass frogs have see-through skin, but red blood should give them away.

Scratch the right spot and your dog's back leg starts pedalling.

Every red blood cell lives for about four months.

Bolas spiders don't build a normal web.

Ants guard aphids from hungry ladybugs, but they aren't doing it to be kind.

In the deep sea, some male anglerfish are tiny.

A young African assassin bug hunts ants, drinks them hollow and glues their empty bodies onto its back.

Every airbag has a small pyrotechnic charge inside it.

A small pan fire looks easy to put out with water, but this is what happens inside the pan when you try.

A gas pump nozzle shuts itself off when your tank is full, with no sensor, chip or electricity.

A Venus flytrap won't close the first time something touches it.

The southern gastric-brooding frog swallowed her own eggs, switched off her stomach acid, and raised her young inside her stomach for about six weeks.

Some farmers give their cows a magnet to swallow on purpose.

Many smoke alarms hold a tiny amount of radioactive americium.

The blue dragon is a tiny sea slug that floats upside down on a swallowed air bubble and eats the tentacles of the Portuguese man o' war.

Licking frozen metal can leave your tongue stuck to it.

When a splinter lets bacteria into your skin, a white blood cell called a neutrophil follows a chemical alarm and squeezes out of your blood vessel to swallow them.

The pistol shrimp snaps its giant claw so fast that it shoots out a jet of water and tears open a bubble.

Wombats are the only animals known to make cube-shaped poop.

A mosquito's 'bite' is really six tiny needles working together.

A toad swallows a bombardier beetle whole, but the beetle carries its own chemical weapon.

Eucalyptus leaves are tough and toxic to most animals, and a baby koala that has only drunk milk can't digest them.

Your stomach is full of acid strong enough to help break down meat, so why doesn't it digest itself?

The jewel wasp stings a cockroach twice: once to freeze its legs and once into its brain.

Scare a myotonic goat and it tips over like a statue.

When a cat sniffs catnip, a chemical called nepetalactone reaches scent sensors in its nose, and its brain releases feel-good chemicals.

That little red glass bulb in a ceiling sprinkler works as a heat fuse.

Many safes hide a thin glass plate behind the lock that holds spring-loaded steel bolts back.

This man kept getting drunk without drinking any alcohol.

The large blue butterfly starts life as a caterpillar on wild thyme.