- The giraffe is a most superior and graceful creature in every way, 'the Queen of Beasts' who, despite his great size — at 200 stone only exceeded by the elephant — appears to glide silently and effortlessly across the plains of Africa. His physique is so many variations on the theme of (elegant) elongation — not just that astonishing seven-foot-long neck, but also those thin but muscular legs, the longest in the animal kingdom. Then there are the long, curly black eyelashes, the three-foot-long (and much prized) tail and an impressively long tongue with which he trims the leaves from the spiky branches of the acacia.
- Towering eighteen feet above the savannah, the giraffe surveys the busy world around (and beneath) him with an almost aristocratic disdain, not just physically but socially aloof, as if aware of his exceptionality. And justifiably so. For while all forms of life are more or less improbable, the giraffe should, by rights, be impossible, so great is the challenge his height poses to the unforgiving law of gravity and its consequences.
- The central conundrum of his existence is how to reconcile the need to keep his head aloft and yet ensure sufficient flexibility to enable him to bend it downwards between his splayed legs to drink. As for staying aloft, a thick band of elasticated tissue tethered to his skull extends down the length of his neck, and along his back to be anchored in the bones of the pelvis. The physical tension exerted by this restraining guy rope is so great that even after death it is only possible to bend a giraffe's neck forward a fraction of its length before it promptly snaps back into the vertical position.
- Seven cervical vertebrae provide the internal scaffolding — each almost a foot long. But while those of other animals (and ourselves) are stacked flat one on top of each other to ensure maximum stability, the flexibility imperative requires those of the giraffe to have a quite different design, jointed together with a ‘ball and socket'. This permits the giraffe's immensely powerful muscles on the front of its neck to overcome the tension of the guy rope and bend his head through an arc of almost 180 degrees.
- This range of movement in turn poses the greatest conceivable challenge to the circulatory system. To ensure sufficient blood is impelled upwards to the brain, the giraffe has the highest pressure (at 280/180) of any animal. But when he bends his neck down, the elevated pressure together with the force of gravity could become so great as to burst a blood vessel and cause a haemorrhage. There are, needless to say, several mechanisms to prevent such a catastrophe, including the reflex opening of the 'rete mirabile', a ‘marvellous network' of arteries through which the blood is shunted, thus bypassing this vital structure.
- By necessity too, the giraffe’s heart needs to be the most powerful of any animal, its muscular walls several inches thick pumping away at a rate of 170 beats per minute. This would generate so much heat as to raise the internal temperature by several degrees were it not for the further unique feature of numerous 'open' thermal windows beneath the skin dissipating the heat outwards.
- The true wonder of the giraffe is that for all we might admire the ingenuity with which he 'solves' these (and many other) physiological problems, he conveys the impression it is the most natural thing imaginable to have so long a neck. This is no bizarre biological anomaly like the peacock's tail, but rather permeates and defines every aspect of his being, from his view of the world (literally and metaphorically) to the rhythmicity of his gait, where the pendulum action of the neck both propels him forward while maintaining his balance — and so on.
- The standard evolutionary1 version would put this all down to the benefits of being in a position to graze the upper branches of the acacia tree. The giraffe no doubt would treat so trivial and simplistic an explanation of his existence with his customary aristocratic disdain.
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