All facts

The bombardier beetle defends itself by firing a chemical spray at about 100 °C.

Inside its abdomen, the insect mixes hydroquinones and hydrogen peroxide in a chamber full of enzymes. The reaction…

Some sea cucumbers expel their own internal organs to distract predators and then grow them back.

When threatened, they contract their body and push out part of the gut and other organs, which act as a decoy. Within…

The Arctic ground squirrel hibernates with its body at about -3 °C, below the freezing point of water.

It is the lowest body temperature ever measured in a mammal. Its blood is supercooled: it cools below zero without…

The archerfish hunts insects resting on leaves above the water by knocking them down with jets of water shot from its mouth.

It presses its tongue against a groove in the roof of its mouth and snaps its gills shut, forming a tube. It hits…

Cuttlefish have W-shaped pupils.

In bright light the pupil closes into a wavy W-shaped curve. Scientists think this shape balances the strong light…

The bar-headed goose crosses the Himalayas and has been recorded flying at over 7,000 metres.

At that altitude the air holds less than half the oxygen found at sea level. These geese have larger lungs…

The saltwater crocodile has the strongest bite ever measured in a living animal.

In a 2012 study, a 4.6-metre male closed its jaws with a force of about 16,400 newtons, roughly 1,700 kilograms…

Clownfish are all born male, and the largest one in the group can turn into a female.

Each anemone hosts a dominant female, a breeding male and several smaller males. If the female dies, the breeding…

Sperm whales sleep vertically, motionless, near the surface of the sea.

Researchers found groups of sperm whales drifting head-up or head-down, not reacting to a passing boat. These naps…

When attacked, the hagfish releases a slime that expands in the water in less than a second and clogs the predator's gills.

Glands along its body release mucus and ultra-thin fibres that unravel on contact with seawater, forming a gel…

In 2021, scientists revived microscopic rotifers that had been frozen for about 24,000 years in Siberian permafrost.

The animals, bdelloid rotifers, were taken from a sample of frozen soil 3.5 metres deep. Once thawed, they started…

Stomach rumbling has a scientific name, borborygmus, and it does not only happen when we are hungry.

The sound comes from gas and fluid being pushed along by contractions of the gut. It is louder on an empty stomach…

A red blood cell lives for about 120 days before being recycled.

Without a nucleus, a red blood cell cannot repair itself and slowly stiffens as it circulates. After about four…

Freshly produced sweat has almost no smell: body odour comes from the bacteria that break it down.

Most sweat is just water and salt. In the armpits, however, some glands also release proteins and fats. Skin bacteria…

Your fingers have no muscles: they are moved by tendons connected to muscles in the palm and forearm.

When we make a fist, the muscles doing the work are in the forearm, which is why it moves when we bend our fingers…

The human tongue is made up of eight different muscles.

Four muscles lie inside the tongue and change its shape; four more anchor it to bone and the skull and change its…

The kidneys filter about 180 litres of blood plasma every day.

All the plasma in the body passes through the kidneys about 60 times a day. More than 99% of the filtered water is…

The lens of the eye never stops growing throughout life.

New layers of cells are added on the outside, like an onion, and the old ones are never removed. The lens becomes…

The headache from eating ice cream too fast is called sphenopalatine ganglioneuralgia.

Cold on the roof of the mouth makes blood vessels constrict and then quickly widen. Nerves in the area read this…

The 'funny bone' is not a bone at all: the shock comes from the ulnar nerve.

At the back of the elbow the ulnar nerve runs through a narrow channel protected only by skin and a little fat. A…

Even identical twins have different iris patterns.

The texture of the iris forms randomly during pregnancy and is not dictated by genes. That is why iris recognition…

The hippocampus of London taxi drivers grows as they memorise the city's streets.

To get a licence, drivers spend years learning about 25,000 streets for an exam called 'The Knowledge'. Brain scans…

Worcestershire sauce is made with fermented anchovies.

Created in 1837 by the chemists Lea and Perrins in Worcester, the sauce contained anchovies, vinegar, molasses…

A red bell pepper has more than twice the vitamin C of an orange, weight for weight.

One hundred grams of raw red pepper contain about 128 milligrams of vitamin C, against around 53 in an orange…