QI: The Second Book of General Ignorance

by John Lloyd

  This has the strange result that it is much easier for a deaf American to make himself understood in Paris than in London.

  STEPHEN Do you know where the sports huddle originated?

  JACK DEE Glenn Huddle?

  What’s a bat’s eyesight like?

  No, they aren’t blind at all.

  Of the 1,100-odd species of bat in the world, not one is sightless – and many can see very well indeed. The notion that bats don’t need eyes because they get about exclusively using echolocation or ‘sonar’ is complete nonsense.

  Fruit bats (also called Megabats) don’t use echolocation at all. They have large eyes, which they use both to navigate and to find their food – which is, as you might expect, fruit. Echolocation isn’t much help in finding food that doesn’t move around. Instead, for fruit-location, they also have a keen sense of smell.

  The Common Vampire bat (Desmodus rotundus) is the only bat that feeds on the blood of mammals. It is such a very long way from blind that it can see a cow 120 metres (400 feet) away: in pitch darkness, in the middle of the night.

  Even microbats – which eat insects and include all British bats, and which do use sonar to hunt – use their (much smaller) eyes for avoiding obstacles, for spotting landmarks,and for working out their flying height. Microbats have good night vision. They see in black and white because they’re nocturnal, whereas fruit bats see in colour because they’re active in the daytime.

  In the Americas there are several species of ‘fishing bats’, such as the Greater Bulldog bat (Noctilio leporinus), which lives by using its keen eyesight and immense feet to drag fish out of the water. It is easily identified, not only by its 66-centimtre (26-inch) wingspan, but also by the repugnant odour of its roosts.

  Very few humans find bats palatable but, for special occasions like weddings, the Chamorro people of Guam like to boil giant fruit bats or ‘flying foxes’ in coconut milk and eat them whole – wings, fur and all. This may explain why so many Chamorro suffer from a rare and terrible neurological condition – ALS-Parkinson dementia complex.

  The bats feed on poisonous cycad plants, whose dangerous neurotoxins are passed on (now lightly flavoured with coconut) to the unfortunate diners.

  Can you name an animal that only eats bamboo?

  Meet the bamboo mite.

  Bamboo mites (Schizotetranychus celarius) eat bamboo and bamboo alone. They are tiny creatures related to spiders and are only 0.4 mm (1/60 inch) long. They form colonies in dense webs under bamboo leaves and suck the chlorophyll from the leaf cells. This makes the leaves mottled and unsightly and a heavy infestation can kill the plant altogether. The mites live about forty days inside their web, only leaving it to defecate. Radical pruning is the safest way to get rid of them, or you could try importing one of several species of larger, predatory mite to eat them (these cost about 1p each via mail order).

  Another parasite that lives uniquely on bamboo is the noxious bamboo mealybug (Dinoderus ocellaris). This pest turns the sap of the bamboo into sugary honeydew. This in turn grows a sooty-black mould that looks nasty but which is irresistible to ants. A practical (if fairly slow) way to control bamboo mealybugs is to eat their larvae. In Thailand bamboo borer grubs are a delicacy, often appearing on menus as ‘fried little white babies’.

  One animal that doesn’t live entirely on bamboo is the Giant panda (Ailuropoda melanoleuca). Admittedly, up to 99 per cent of its diet is made up of bamboo, but pandas will happily eat small mammals, fish and carrion if they can rouse themselves to catch any.

  The problem is that pandas are built like carnivores but eat like herbivores. Bamboo is available all year round, but it’s so low in nutrition that, to satisfy their basic needs, pandas must spend twelve hours a day munching the equivalent of a hay bale of the stuff. This leaves little time (or energy) for hunting or gathering. Nor does it produce enough fat to hibernate in the winter. Instead, it generates a tremendous amount of waste. Pandas defecate more than forty times a day – excreting about half the weight of what they eat – and their droppings are so fibrous that one Thai zoo uses them to make souvenir paper.

  Perhaps because of the endless regime of eating and sleeping, pandas aren’t very sociable. When it comes to defending their territory, they avoid energy-sapping confrontations. Instead, they keep other pandas at bay by marking their boundaries with scent. They do this in four distinct ways, the most unusual being to leave a mark while doing a handstand. The higher the pee, the more dominant the signal is rated by potential rivals. No other animal in the world does this.

  As well as keeping the 2,000 surviving wild giant pandas alive, bamboo has other extraordinary qualities. It is the world’s fastest-growing plant: one species in China grows a metre (about 3 feet) a day (that’s nearly 8 centimetres, or 3 inches, an hour) and, when fully grown, can reach 60 metres (200 feet) tall. It also has a ‘bend-factor’ ten times greater than that of steel, making it ideal for construction – almost all the scaffolding in Hong Kong is made of bamboo.

  Which is hairier: human or chimpanzee?

  Humans may look less hairy than a chimpanzee, but we have the same number of hair follicles – about 5 million – on our bodies, of which only 100,000 (2 per cent) are on our scalps.

  Our hair has evolved to be finer and more transparent than in other primates. We lost our fur, and no one knows why. One theory is that it was to reduce lice. Another is that, when our ancestors moved out of the forests on to the savannah about 1.7 million years ago, we needed to lose body hair to stop overheating. As we became less hairy, we became darker-skinned to protect our skin from the sun. But that doesn’t explain why the Inuit of the Arctic have less body hair than many sub-Saharan Africans.

  Nor does it explain why our scalp hair is programmed to grow for such long periods: left to its own devices, it would grow down past our waists. Other mammalian fur is more like our body hair – it grows to a set length and then is replaced. (Nor can we explain why some men sprout luxuriant hair out of their ears, noses, eyebrows and backs, even as their heads go bald.)

  One theory links our loss of fur with increased brain size. A bigger brain creates more heat; in order to keep our temperature under control, we evolved to sweat heavily (sweating is hopeless if you have fur). So, the less fur we had, the more efficient our cooling system became and the bigger our brains grew. Also, as humans walked upright, the only place we still needed hair was on the head, to protect our expanding brains against the sun.

  Another more extreme hypothesis suggests we evolved from ‘aquatic apes’. This supposes that 8 million years ago the ancestors of modern humans lived a semi-aquatic lifestyle, foraging for food in shallow waters. As fur is not an effective insulator in water, we evolved to replace it, as other aquatic mammals have, with higher levels of body fat. Unfortunately, there isn’t any fossil evidence for aquatic humans (or apes) at all.

  Yet another idea is that hairlessness, once it had started to evolve, was reinforced by sexual selection – in other words it became attractive to the opposite sex. Charles Darwin went along with this (though, given that, it’s odd he chose to have such an enormous beard) and it may be why women are less hairy than men and why smooth, clear skin has become a sign of good health.

  Nobody’s really sure, though. As leading palaeoanthropologist Ian Tattersall recently remarked: ‘There are all kinds of notions as to the advantage of hair loss, but they are all just-so stories.’

  What did Neanderthals look like?

  A lot like us.

  The latest reconstructions of Neanderthals look very similar to humans. If you gave one a haircut and a tracksuit, it wouldn’t look out of place on a bus.

  The first fossilised remains of humanity’s closest cousins were found in 1856 near Düsseldorf in the Neander river valley, hence the word Neanderthal (Tal, then spelt Thal, is German for ‘valley’). Homo neanderthalensis used tools, wore jewellery, had religious rites, buried his dead and could probably talk. Like us they had the essential hyoid bone (
which holds the root of the tongue in place) and recent genetic analysis shows they had exactly the same ‘language gene’ (FOXP2) that humans do. Using the word Neanderthal to mean ‘oafish’ or ‘unreconstructed’ is unfair. In fact, this notion derives from a misinterpretation of the very first reconstruction of a Neanderthal skeleton.

  It was the work of a French palaeontologist called Pierre Marcellin Boule (1861–1942) who in 1911 put together a specimen with a curved spine, a stoop, bent knees, and a head and hips that jutted forward. In 1957 the skeleton was reexamined and it became clear that the original owner had suffered from a grossly deforming type of osteoarthritis. Not only did this not represent the average Neanderthal, but Boule had also let his preconceptions affect his work, giving the skeleton an opposable big toe like a great ape, even though the bones didn’t provide any evidence for such a conclusion.

  Neanderthals had barrel-shaped chests and broad, projecting noses – traits some palaeoanthropologists believe helped them breathe better when chasing prey in cold environments. They had bigger brains than modern humans, but they couldn’t run as fast and were shorter and less adept at using tools. What they lacked in height they made up for in strength: Neanderthal females had bigger biceps than the average male human does today.

  Humans and Neanderthals diverged into separate species somewhere between 440,000 and 270,000 years ago. Early Neanderthals moved out of Africa into the Middle East and northern Europe much sooner than Homo sapiens did, and lived there for four times as long. They became extinct 30,000 years ago (the last recorded Neanderthal community was on Gibraltar), which means that humans and Neanderthals coexisted for at least 12,000 years.

  No one knows why the Neanderthals died out. Were they out-competed by humans or did they (for some unknown reason) fail to adapt to the last Ice Age, when Europe became a frozen, sparsely vegetated semi-desert? The oldest known ornaments in Europe (made from shells) were the work of Neanderthals and some researchers now think that humans might have learned ritual and even culture from them during the 120 centuries we shared.

  But the most startling fact to emerge from analysis of the genome of the Neanderthals is that they interbred with us. So, unless you are a pure black African, between 1 per cent and 4 per cent of you is Neanderthal.

  STEPHEN How would you spot a Neanderthal if you saw one on a bus?

  JACK DEE He’d be the one who comes and sits next to me.

  JO BRAND He’s the one already sitting next to me,’cause I’m married to him.

  STEPHEN Is this going to be the ‘humiliate my husband’ show? JO It’s all right, he doesn’t watch this. He doesn’t really understand it.

  Which part of you is evolving fastest?

  It’s your nose.

  It was once impossible to know how our sensory organs evolved because the soft parts of our bodies don’t survive in the fossil record. However, genetic analysis at Cornell University has led ‘sensory psychologist’ Avery Gilbert to believe that the nose is the fastest-evolving human organ.

  In mammals the largest single family of genes controls the sense of smell. The study of the human genome shows that ours has altered much more rapidly than those of our closest living relatives, the great apes. This means we sniff less, but taste more, sending aromas from the back of the throat to the nose as we chew. Known as ‘retronasal olfaction’ or ‘back-of-the-nose smelling’ (as opposed to orthonasal smelling through the nostrils) this ability to savour food as we are eating is almost unique to humans. In Avery’s words: ‘The human nose evolved to serve the human mouth.’

  Two events may have contributed to this. The first was cooking with fire, first discovered 1.8 million years ago by our ancestor Homo erectus, bringing with it the enticing smells of roast meat and caramelised fruit. The second was the domestication of animals around 15,000 years ago, closely followed by the invention of farming. This brought a whole new range of flavours (yogurt, milk, cheese, bread and toast) and the domestication of the dog gave us a companion species with an extremely acute sense of smell. One theory is that our ancestors delegated the practical scent-tracking function of our noses to dogs, while we concentrated on the ever more complex and delicious aromas coming from the cooking pot. Eating together around the campfire transformed human culture: our shared sense of taste helped to civilise us.

  The nose may be our fastest-evolving organ, but further analysis of the human genome shows that we are also evolving elsewhere. Our hair is becoming less thick, but our hearing (perhaps as a result of developing language) is much better than that of chimpanzees. More alarmingly, the Y chromosome, the one that makes a person male (men have both an X and a Y chromosome) is shrinking. It’s lost 1,393 of its original 1,438 genes over the last 300 million years. The geneticist Steve Jones points out that one consequence of this is that women are now genetically closer to chimpanzees than men are, because the two X chromosomes they possess have changed much less rapidly.

  There’s a widespread assumption that human beings have stopped evolving, because technological advances have insulated us from the environmental pressures that drive natural selection. However, the latest genome research suggests the rate of evolutionary change among humans is much the same as that observed in the rest of nature.

  A good example of this is lactose tolerance (inability to digest milk) in adults, which has arisen in some parts of the world (but not others) as the result of a single genetic mutation that took place no more than 5,000 years ago.

  What were Bronze Age tools made of?

  Stone, mostly.

  The Bronze Age, which in Europe is dated at 2300–600 BC, began when mankind first discovered how to make and use bronze, but this would have been a gradual industrial revolution. For much of the period, old technology (using stone and bone) would have been more widespread than metal. Bronze would have been rare and expensive, so most everyday tools and weapons would still have been made from flint and other familiar materials.

  And, just as stone flourished in the Bronze Age, so bronze-working didn’t reach its peak until well into the Iron Age (1200 BC–AD 400).

  We still use all three materials today. In the twenty-first century, alongside plastic bags and silicon chips, we still continue to produce iron railings, bronze bearings and statues, gravestones and grinding stones. The last people in Britain to make a living working with flint were the flintknappers who supplied the gunflints for firearms. It was a profession that only died out in the nineteenth century, when the percussion cap replaced the flintlock.

  The ‘Three-Age System’ – in which the Bronze Age follows the Stone Age, and is succeeded by the Iron Age – stems from the early nineteenth century. It was the brainchild of Christian Jürgensen Thomsen (1788–1865), a Danish museum curator, who was looking for a nice neat way of arranging his exhibits. It was never intended to be more than a fairly crude means of placing artefacts in a chronological relationship with each other, by classifying them according to the relative sophistication of their manufacture.

  Many archaeologists believe that the Stone Age – which is itself split into three eras (the Old, Middle and New Stone ages) – was probably more of a Wood Age, but that wood’s predominant role in pre-history has been hidden by the fact that wooden artefacts rot, while stone ones don’t.

  What was not Made in China and not made of china?

  Glass.

  Though the Chinese invented the compass, the flushing toilet, gunpowder, paper, the canal lock and the suspension bridge long before anyone else, the scientific revolution that transformed the West between the sixteenth and eighteenth centuries completely passed them by.

  The reason for this is that they also invented tea.

  The earliest known glass artefacts are Egyptian and date back to 1350 BC, but it was the Romans who first produced transparent glass. They liked the way it enabled them to admire the colour of their wine.

  By the time the Egyptians worked out how to make glass, the Chinese had been drinking tea (traditionally they
began in 2737 BC) for almost 1,400 years. Its colour was less important to them than temperature, and they found it was best served in their most famous invention of all: fine porcelain, or ‘china’.

  Since they had no particular use for it, early Chinese glass was thick, opaque and brittle. They mainly used it for making children’s toys – and soon gave up on it altogether. For almost 500 years, from the end of the fourteenth century until the nineteenth, no glass was made in China at all.

  Meanwhile, in 1291 the Republic of Venice, concerned about the fire risk to its wooden buildings, moved its glass furnaces offshore to the island of Murano. Here, inspired by migrant Islamic craftsmen, the inhabitants learned to make the finest glass in the world, giving them a monopoly that lasted for centuries

  The impact of high-grade glass on Western culture cannot be overstated. The invention of spectacles towards the end of the thirteenth century added at least fifteen years to the academic and scientific careers of men whose work depended on reading. The precise reflection of glass mirrors led to the discovery of perspective in Renaissance painting. Glass beakers and test tubes transformed ancient alchemy into the modern science of chemistry.

  The microscope and the telescope, invented within a few years of each other at the end of the sixteenth century, opened up two new universes: the very distant and the very small.