A koala bear is not a bear. A king crab is not a crab. A guinea pig is neither. And then there's the panda, which everyone will tell you isn't a bear — and is.

A bar-tailed godwit flew from Alaska to New Zealand without landing once — eight days in the air over open ocean, no map, no landmarks, no second chances. Ask an adult how it knew the way and you will get one word. That word is not an answer.

A dolphin's tail beats up and down. A shark's sweeps side to side. That is not a small difference — it is the fingerprint of an animal whose ancestors once walked.

Cancer starts when one cell goes wrong. A blue whale has more than a thousand times as many cells as you do and lives for a century. By every sensible calculation, whales should not be possible. They are fine. Nobody is completely sure why.

A bee looking at a flower sees markings that are not there for you. A snake can find a mouse in total darkness by its warmth. And the animal with sixteen kinds of colour detector turns out to be worse at telling colours apart than you are.

An ant can carry many times its own weight, so an ant the size of a horse would be unstoppable. Except it would not be able to stand up, or breathe, and its legs would break under it while it was still trying. The reason is arithmetic you can do in a minute.