QI: The Book of General Ignorance - the Noticeably Stouter Edition (28 page)

They don’t care, it’s all the same to them.

Cobras in snake-charming acts are responding to the
sight
of the flute, not its sound.

Snakes don’t really ‘hear’ music though they are certainly not deaf. They have no external ears or eardrums, but can sense vibrations transmitted up from the ground into their jaw and the belly muscles. They also seem to be able to detect airborne sounds via an inner ear.

It used to be thought that snakes could not hear at all because they don’t respond to loud noises but research at
Princeton has shown that they have acute hearing.

The key discovery was how the snake’s inner ear functions. Snakes were wired to voltmeters and the effect of airborne sound on their brains measured. It appears that their hearing is ‘tuned’ to the frequency range of noises and vibrations made by the movement of larger animals, so music would be meaningless to them.

‘Charmed’ cobras stand upright if threatened and sway in response to the movement of the instrument. If they strike at the flute, they hurt themselves, so they don’t do it again.

Most cobras have had their fangs removed but, even so, they can only strike at a distance within their own length, rather as if you put your elbow on a table and strike downward with your hand.

The cobra’s natural attitude is defensive, not aggressive.

Violin strings are not made of catgut, and never have been.

This is a myth started by medieval Italian violin-makers who had discovered that sheep intestines made good strings for their instruments. Killing a cat brought terribly bad luck,
so they protected their invention by telling everyone else their strings were made from the intestines of cats.

The legend was that a saddle-maker called Erasmo, in the Abruzzi mountain village of Salle, near Pescara, heard the wind blowing through the strands of drying sheep’s gut one day and thought that they might make a good string for the early violin known as the renaissance fiddle.

Salle became the centre of violin string production for 600 years and Erasmo was canonised as the patron saint of string-makers.

Bad earthquakes in 1905 and 1933 brought an end to the industry in Salle itself, but two of the world’s leading string makers – D’Addario and Mari – are still run by Sallese families.

Until 1750 all violins used sheep’s-gut strings. The gut must be removed from the animal when warm, stripped of fat and waste and soaked in cold water. The best sections are then cut into ribbons and twisted and scraped until a string of the required thickness is made.

Today a combination of gut, nylon and steel are used, although most aficionados still believe that gut produces the warmest tone.

Richard Wagner circulated a terrible story to discredit Brahms, whom he loathed. He claimed Brahms had received a gift from Czech composer Antonín Dvo
ř
ák of a ‘Bohemian sparrow-slaying bow’. With this he allegedly took pot-shots at passing cats from his Viennese apartment window.

Wagner went on: ‘After spearing the poor brutes, he reeled them in to his room after the manner of a trout-fisher. Then he eagerly listened to the expiring groans of his victims and carefully jotted down in his notebook their
ante mortem
remarks.’

Wagner had never visited Brahms or seen his apartment; there seems to be no record of such a ‘sparrow bow’ existing, let alone being sent by Dvo
ř
ák.

Cats tend to die, like most other species, in silence.

Despite this, the rumours of felicide have stuck to Brahms and the claim has been reproduced as fact in several biographies.

Any of them above the seventh floor.

Higher than the seventh floor, it doesn’t really matter how far the cat falls, as long as its oxygen holds out.

Like many small animals, cats have a non-fatal terminal velocity – in cats this is about 100 kph or 60 mph. Once they relax, they orientate themselves, spread out, and parachute to earth like a squirrel.

Terminal velocity is the point at which a body’s weight equalises against the resistance of the air and it stops accelerating – in humans it’s nearly 195 kph (about 120 mph), reached in free fall at about 550 metres (1,800 feet).

There are cats on record that have fallen thirty storeys or more without ill effects. One cat is known to have survived a forty-six-storey fall, and there is even evidence of a cat deliberately thrown out of a Cessna aircraft at 244 metres (800 feet) that survived.

A 1987 paper in the
Journal of the American Veterinary Medical
Association
studied 132 cases of cats that had fallen out of high-rise windows in New York. On average they fell 5.5 storeys. Ninety per cent survived, though many suffered serious injuries. The data showed that injuries rose proportionally to the number of storeys fallen – up to seven storeys. Above seven storeys, the number of injuries per cat sharply declined. In other words, the further the cat fell, the better its chances.

The most famous human free-falls are Vesna Vulović, who fell 10,600 metres (34,777 feet) when a terrorist bomb destroyed her Yugoslavian airlines DC-10 in 1972, and Flight Sergeant Nicholas Alkemade, an RAF tailgunner who leaped from his burning Lancaster in 1944, falling 5,800 metres (19,000 feet).

Vulović broke both legs, and suffered some spinal damage, but was saved by the fact that her seat and the toilet booth it was attached to took the impact.

Alkemade’s fall was broken by a pine tree and then a snowdrift. He escaped unharmed and remained sitting in the snow, quietly smoking a cigarette.

The dodo (
Raphus cucullatus
) has the unenviable double distinction as a byword for being both dead and stupid.

A flightless native of Mauritius, it evolved in an environment free of ground-based predators and was wiped out in less than a hundred years by the destruction of its forest habitat and the introduction of pigs, rats and dogs to the island.

Improbably enough, the dodo was a species of pigeon, but, unlike the other famous extinct fowl, the passenger pigeon, it was not hunted for food as it was barely edible – the Dutch called it
walgvogel
, the disgusting bird.

The Portugese name
dodo
is also unkind; it means ‘simpleton’ (as in ‘durrr-durrr’), a reference to the fact that it had no fear of humans so didn’t run away, making it of limited value as a sporting bird. It was extinct by 1700.

In 1755, the director of the Ashmolean Museum in Oxford decided that their specimen was too moth-eaten to keep and threw it on a bonfire. It was the only preserved dodo in existence. A passing employee tried to rescue it, but could only save its head and part of one limb.

For a long time, all that was known about the dodo derived from these remains, a handful of descriptions, three or four oil paintings and a few bones. We knew more about some dinosaurs. In December 2005, a large cache of bones was found on Mauritius which has allowed for a much more accurate reconstruction.

From the time of its extinction until the publication of
Alice in Wonderland
in 1865 the dodo was pretty thoroughly forgotten. Charles Dodgson (better known as Lewis Carroll) was an Oxford maths lecturer who must have seen it in the Ashmolean.

The dodo appears in
Alice in Wonderland
in the Caucus Race, a ‘race’ with no precise start or end, in which everyone gets a prize. Each of the birds corresponds to a member of the boating party present when Dodgson first told the story and the dodo is said to be based on himself.

Sir John Tenniel’s illustrations in the book quickly made the bird famous. The phrase ‘dead as a dodo’ also dates from this period.

Wrong.

No ostrich has ever been observed to bury its head in the sand. It would suffocate if it did. When danger threatens, ostriches run away like any other sensible animal.

The myth about ostriches may have arisen because they sometimes lie down in their nest (which is a shallow hole in the ground) with their necks stretched out flat and scan the horizon for trouble. If the predator gets too close they get up and leg it. They can run at speeds up to 65 kph (40 mph) for thirty minutes.

The ostrich is the largest bird in the world: a male can reach 2.7 m (9 feet) tall, but their brains are the size of a walnut, smaller than their eyeballs.

The ostrich was classified by Linnaeus as
Struthio camelus
or ‘sparrow camel’, presumably because they live in the desert and have long, camel-like necks. The Greek for ostrich was
ho megas strouthos
, ‘the big sparrow’.

The head-burying myth was first reported by the Roman historian Pliny the Elder, who also thought ostriches could hatch their eggs by looking at them aggressively.

He didn’t mention their ability to swallow odd things.

As well as the stones they use to aid digestion, ostriches will eat iron, copper, brick or glass. One ostrich in London Zoo was found to have eaten a metre-length of rope, a spool of film, an alarm clock, a cycle valve, a pencil, a comb, three gloves, a handkerchief, pieces of a gold necklace, a watch and a number of coins.

Ostriches in Namibia have been known to eat diamonds.

A worm, usually.

Pearls hardly ever result from a grain of sand or grit getting into an oyster’s shell. There is perhaps a thousand-to-one chance of a pearl forming that way. If all it took were sand – which oysters spend their lives sucking in and blowing out – pearls would be far more common.

Oysters have numerous predators. Parasitic worms, starfish, snails, sponges and mussels attack them by prising open or drilling into their shells. The larger creatures usually kill the oyster, but the worms trigger its defence mechanism and may be contained in a ‘pearl sac’ then smothered by repeated coatings of nacre, to stop their irritating wriggles. Nacre is an extraordinary substance: a mixture of calcium carbonate (from
which marble is made) and an organic secretion very like keratin (the material responsible for human fingernails). The aggressors suffer a glorious doom. The nineteenth-century French natural scientist Raphael Dubois said: ‘The most beautiful pearl is nothing more, in fact, than the brilliant sarcophagus of a worm.’

Oysters with parasites in them are often spurned by polite oyster society and go and live under rocks out of the way, which makes it slightly easier for pearl-fishers to find them. Nevertheless, a finished pearl can tale up to fifteen years to make and a ton of oysters might yield as few as three pearls. The chances of any of them being perfectly spherical are, literally, one in a million.

Cultured pearls are an attempt to fast-track this process. An oyster is opened and a bead of mussel shell inserted, along with part of another oyster’s mantle (the fold of an oyster’s skin covering its internal organs). The ‘donor’ oyster’s mantle fuses with the tissue of its host, and is stimulated into producing a pearl sac, coating the mussel bead with nacre.

Pearls can be found in clams, whelks, conchs, abalones, mussels and snails as well as in oysters. But don’t get too excited as you shuck your English natives this Christmas. The pearl oyster is actually a kind of scallop – and is about as closely related to the edible variety as humans are to marmosets. Edible oysters don’t produce nacre – their ‘pearls’ look like rather dull pebbles.