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Dermatology (!)

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62731.  Thu Mar 30, 2006 7:23 am Reply with quote

Question: Why don't geese get goose-bumps?

Forfeit: They're too dem hard.

Answer: They don't have arrector muscles.

Notes: All land mammals, humans included, suffer a condition known as horripilation which makes their hair stand on end when they're cold or frightened. Having the hair stand on end when cold keeps more of the skin-warmed air next to your body, like a string vest, and when frightened, having your hair 'bristle' makes you look larger and more intimidating to an enemy (which is less energy intensive than actually being bigger).

Preparing for a fight also draws the blood away from the skin's surface (making one go pale, and lessening the chances of blood loss from a wound), which also makes one colder, increasing the bristling reaction. The process occurs when the arrector muscles, attached to each and every hair follicle, pull hard and make the hair stand on end. When you warm up or when the adrenaline levels subside, the muscles relax again.

Goose bumps are noticeable where humans no longer have much hair, on the arms and legs, and so have no function other than to look silly (and possibly provoke hugging). The bumps are the arrector muscles pulling on the remains of the follicles in the skin. Because geese (and all birds) have no hair, they do not get goose bumps, but convergent evolution has lent them a similar solution to the problem of keeping warm - they can plump up their feathers, as seen on avian winter residents.

The word horripilation comes from the same root as 'horrid' and 'horrific', meaning 'bristling' or 'standing on end', so humans are much more horrible than geese, but not as horrible as porcupines.

Despite the urban myth, porcupines cannot shoot quills from their backs. They do erect them as described, however, and then quickly run backwards towards their attacker.

In France, goose bumps are known as 'chicken skin'. Humans get about 20 square feet of new skin per week as the old, dead layers on the surface continually peel away as 'dander'.

Pictures Some nice goose-bumps. Perhaps a porcupine.


Frederick The Monk
62760.  Thu Mar 30, 2006 8:19 am Reply with quote

Link to dust and underground fluffers.


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