Why Is a Giraffe's Neck So Long?

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Seven bones, just very big ones.

You have seven bones in your neck. So does a giraffe, and so does a mouse. The giraffe did not grow extra pieces — each of its seven is simply as long as your forearm or more.

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It eats where nothing else can.

In a dry season the low leaves get stripped bare by everything else. A giraffe simply reaches over the top of the competition, into a shelf of leaves no other animal on the plain can touch.

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The heart has to push blood uphill.

Getting blood two metres straight up to the brain takes serious pressure. A giraffe's heart has a thick, powerful wall and drives blood at roughly twice the pressure of yours.

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Bending down should knock it out.

When the head drops to drink, all that pressure suddenly points the wrong way. Valves in the neck veins snap shut and a spongy web of vessels near the brain soaks up the surge, so nothing bursts.

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The legs need tight skin.

That same pressure would push fluid out into the feet. A giraffe's lower legs are wrapped in skin so tight it works like a support stocking, holding everything in.

A giraffe's tongue is about half a metre long, and dark on top — thought to be a sunburn shield for something out in the sun all day.