Wacky Facts

Research on crows showed they remember people who threatened them and even teach other crows to scold those people.

These Mexican salamanders can regenerate limbs, parts of the spinal cord and even heart and brain tissue, which makes them important in regeneration research.

The North American wood frog stops its heart in winter and thaws back to life in spring.

A 2022 study found sleeping glass frogs pull most of their red blood cells out of circulation and pack them into the liver, becoming two to three times more transparent.

In very dry conditions some snails seal themselves in their shells and become dormant for long periods — a state called aestivation — until moisture returns.

Oxygen enters through tiny holes called spiracles along their bodies and travels through tubes to their cells.

A strong valve at the entrance to the stomach and the angle of the oesophagus make vomiting almost impossible for horses.

The female king cobra gathers leaves into a mound nest for her eggs and guards it — unusual among snakes.

Collective nouns for animals are often playful: a parliament of owls, a murder of crows, a tower of giraffes and a flamboyance of flamingos. Many date back to hunting books from the 15th century.

Ostrich eyes are about 5 cm across, the largest of any land animal.

When stressed or injured, Turritopsis dohrnii can revert from its adult medusa form to the polyp stage and start its life cycle again.

The dark stripes are visible on a tiger’s shaved skin too. No two tigers have the same stripe pattern.

Experiments suggest pigeons can pass forms of mirror self-recognition tests after training, and they can also distinguish between many images and even letters of the alphabet.

These half-millimetre “water bears” can dry out into a dormant state. In 2007 some were carried into orbit on the outside of a spacecraft and exposed to vacuum and radiation; a number of them revived and even reproduced after returning to Earth.

Elephants can detect low-frequency rumbles and ground vibrations through sensitive cells in their feet and trunk, which may help them sense distant herds or storms.

Research on cattle vocalisations shows individual cows have distinct voices that herd mates recognise. Calves and mothers can identify each other by call.

Its low water content and acidity stop bacteria from growing. Edible honey has been found in ancient Egyptian tombs.

The long train belongs to the male Indian peafowl and is used in courtship displays. It is shed and regrown every year.

Both have seven cervical vertebrae; a giraffe’s are simply much longer, each up to about 25 cm.

Some bamboo species are among the fastest-growing plants on Earth, growing up to about 90 cm in 24 hours.

Flying squirrels glide, but bats power their flight with wings made of skin stretched over long finger bones.

This popular claim is a myth: pigs can raise their heads and look upwards, though their neck anatomy limits it somewhat.

Measurements of a blue whale heart preserved in Canada put it at around 180 kg. Blue whales are the largest animals known to have ever lived, up to about 30 m long.

Taste receptors on their feet let female butterflies check whether a leaf is the right plant to lay eggs on.

The earliest sharks appear in the fossil record around 450 million years ago; the first true trees appeared roughly 385 million years ago.

Their diet of eucalyptus leaves is low in nutrients and hard to digest, so koalas save energy by sleeping or resting for most of the day.

By slowing their heart rate, sloths can stay underwater for up to about 40 minutes.

Sea stars use a nerve net instead of a brain, and pump sea water through a water-vascular system instead of blood. Many can regrow lost arms.

Cheetahs are the fastest land animals, reaching around 100–110 km/h in short bursts, but they tire after a few hundred metres.

Elephants’ front legs bend like knees but are actually wrists. What makes them unusual is that they cannot jump at all.

A forager returning to the hive performs a “waggle dance”: the angle of the dance shows the direction of the food relative to the Sun, and the length of the waggle shows the distance. Karl von Frisch shared the 1973 Nobel Prize for decoding it.

Most of a shrimp’s vital organs, including the heart, sit in the cephalothorax — the fused head and chest section.

Bottlenose dolphins develop signature whistles and respond when others copy their whistle.

Asian elephants have passed the mirror test, a sign of self-awareness shared with great apes, dolphins and magpies.

Their wings rotate at the shoulder and beat in a figure-eight pattern, letting them hover, fly backwards and even briefly upside down. Small species beat their wings dozens of times per second.

Two hearts pump blood through the gills and one through the body. Their blood uses copper-based haemocyanin, which makes it blue.

Squirrels bury nuts to eat later but fail to recover many, some of which grow into trees.

No two tigers have the same stripe pattern, and the stripes are also on their skin, not just the fur. India has the world’s largest wild tiger population.

Lake Natron is so alkaline that animals which die in it become coated in mineral deposits and preserved. Yet it is the main breeding site of lesser flamingos.

Several whiptail lizard species in North America consist only of females that lay viable eggs without fertilisation.

The cashew nut hangs below a fleshy “cashew apple”. The shell contains an irritating oil, which is why cashews are always sold shelled and processed.

The last wild Asiatic lions live in and around Gir forest in Gujarat; their numbers have grown to several hundred.

A 2016 study used radiocarbon dating of the lens of the eye; the oldest shark studied was estimated at roughly 270 to 500 years old.

Flamingos get their pink colour from carotenoid pigments in the algae and shrimp they eat.

They sense carbon dioxide from metres away, then body heat and skin odours up close.

Collective nouns like this date back to medieval English hunting books.

Resting sea otters often float together in groups called rafts, and some hold paws or wrap themselves in kelp so they do not drift apart.

University of Washington researchers wore masks while trapping crows. Years later, crows still scolded anyone wearing the “dangerous” mask — including birds that were never trapped.

Studies of dairy cattle found their heart rates and stress levels were lower when paired with a preferred companion than with a random cow.

Males shed the long train feathers after the breeding season and grow them back before the next.

Researchers found that the elasticity of the wombat’s intestine varies along its length, which shapes droppings into cubes. Wombats stack them to mark territory — the flat sides stop them rolling away.

Mantis shrimp strike with club-like limbs at speeds around 23 m/s, fast enough to create cavitation bubbles and break snail shells.

Male gentoo and Adélie penguins search for smooth pebbles and present them to females; pebbles are used to build nests.

Researchers recorded ultrasonic chirps from rats being tickled, which they compare to laughter.

Several turtle species absorb oxygen through their cloaca, helping them stay underwater for long periods.

Experiments show goldfish can be trained to respond to sounds and remember tasks for months.