IELTS Academic Reading Practice Test 457

The narwhal is a small whale, rarely longer than five metres and weighing perhaps a tonne and a half, that spends its entire life in the Arctic. It belongs to the same family as the beluga, and the two are the only whales without a dorsal fin — an adaptation that lets them swim beneath a ceiling of ice without snagging themselves. Narwhals are mottled grey for most of their lives, though the oldest animals may be almost white. For centuries, sailors returning from northern waters brought back long, spiralled tusks that were sold across Europe as the horns of unicorns.

The tusk is not a horn at all but an overgrown tooth. In most males, and in a small minority of females, the left upper canine continues to grow through the lip and emerges as a spiral shaft that may reach two and a half metres. Unlike the teeth of other mammals, it has no enamel coating, and its outer layer is porous. The tusk is hollow for part of its length and contains millions of tiny channels, called tubules, which run from the outer surface to the living pulp at its centre, where blood vessels and nerve tissue lie.

Why males should carry such an elaborate structure has puzzled naturalists. The obvious explanation, that it is a weapon used in fights over mates, is not well supported: serious injury is rarely seen. A more recent suggestion is that the tusk works as a sensory organ. When researchers attached instruments to narwhals, the animals' heart rates rose sharply as the tusks were exposed to water of different saltiness, which implies that the tubules can detect changes in their surroundings. The tusk may also act as a display, signalling a male's size and status to rivals.

Much of what narwhals do takes place out of sight. In summer they gather in shallow bays and fjords, but in winter they move into deep water covered by dense pack ice, keeping to cracks and open patches known as leads where they can surface to breathe. They feed mainly on fish, squid and shrimp, including Greenland halibut and Arctic cod. Dives of more than a kilometre are routine, and dives of over 1,500 metres have been recorded, so the whales may spend much of the day below the ice, following the steep underwater slopes where their prey collect.

Narwhals are sociable animals, travelling in groups that may number only a few in summer but can contain hundreds, and occasionally more than a thousand, during the winter migration. They communicate with clicks, whistles and pulsed calls, some of which appear to be used for echolocation — producing sound and interpreting the returning echoes to build a picture of the surroundings in darkness or murky water. Genetic studies suggest that populations are quite separate, and that whales from different regions rarely mix, which matters for conservation: a local decline is unlikely to be made up by animals from elsewhere.

Two predators take a significant toll. Orcas hunt narwhals in open water, and polar bears wait at breathing holes in the ice and strike when a whale comes up for air. Humans have hunted them for at least a thousand years, and Inuit communities in Canada and Greenland still take a limited number each year, using the meat for food and the skin, which is rich in vitamin C, as a delicacy. In the medieval period, however, the trade in tusks was on a different scale: carved tusks were presented to churches and princes, and a throne in Copenhagen was built largely from them.

Because hardly any Europeans had seen a living narwhal, the tusk could be presented as evidence of a creature that appeared in the Bible. Unicorn horn was believed to neutralise poison, and powdered tusk was sold as medicine at prices that could exceed those of gold. The deception was not deliberate on the part of the Inuit hunters, who merely sold what they had, and Norse traders appear to have encouraged the misunderstanding. Ground narwhal tusk remained in the inventories of European apothecaries well into the eighteenth century.

Today the total population is thought to be well over 100,000, but the picture is uneven. Some populations appear stable; others, particularly in parts of west Greenland, have fallen. The species faces a combination of pressures. Climate change is altering the extent and timing of sea ice, which affects both the whales' access to breathing holes and the behaviour of their prey. Increased shipping in Arctic waters brings underwater noise that can mask the sounds the whales rely on, and oil and gas exploration adds further disturbance, to which narwhals are thought to be unusually sensitive.

Studying narwhals is difficult and expensive. They live in remote regions, often in darkness or bad weather, and they surface only briefly. Much of what is known comes from a small number of tagged animals and from genetic samples collected during subsistence hunts. Conservationists argue that this is precisely why caution is needed: a species that is slow to reproduce, and that depends on a habitat changing faster than at any point in its history, cannot easily recover from mistakes.

What is certain is that the narwhal remains one of the least understood large mammals on Earth. The animal that supplied the unicorn's horn is still, in many respects, a mystery, and the tusk at the centre of its story has never been fully explained.

Long before children can add or subtract, they begin to count. The process looks effortless, yet it rests on several distinct discoveries that must be made in the right order, and the journey from reciting a string of words to understanding what those words mean takes years. Studies of children in many countries suggest that the timing varies with language, schooling and how much number talk a child hears at home, but the sequence itself is remarkably consistent.

In the late 1970s two psychologists set out what counting actually requires. A child must produce one number word for each object, matching words to objects in a fixed order and always in the same sequence. The last word spoken must stand for the total, an insight known as the cardinal principle. The arrangement of the objects must not matter: a row of buttons counted from left to right has the same total as the same row counted from right to left. And anything can be counted — toys, footsteps, days — provided the procedure is followed. Children can often recite the words long before they obey these rules, which is why a three-year-old may count four objects correctly and then, asked to hand over four, present a random handful.

Very young children manage without counting words at all. Like many animals, they can recognise the size of a small collection instantly, a capacity called subitising, which works reliably for one, two, three and sometimes four objects. Beyond that, estimation takes over. Humans, like other species, possess an approximate number system that allows rough comparisons of large quantities without any counting, distinguishing, say, twenty from forty but not twenty from twenty-five. The precision of this sense improves steadily through childhood.

The ability to appreciate small quantities appears very early. In experiments in the 1990s, five-month-old infants watched as an object was placed behind a screen and a second object added. When the screen was removed, the babies looked longer if only one object was there than if there were two, which researchers interpreted as surprise at an impossible result. Infants of a few months can also tell a large collection from a much smaller one, though they fail when the two quantities are close in size.

The most striking evidence comes from a simple game. A child is asked to hand over a particular number of objects. Children of two and a half can usually manage one; at around three they can give two or three; but for several months they cannot give four, offering either a random heap or a number they seem to pluck from the air. Then, quite suddenly, the same child succeeds at every number the game requires. Most children experience this change between the ages of three and a half and four, and it marks the moment when the counting words stop being a rhyme and become a system.

The words themselves make a difference. In English a child must memorise 'eleven' and 'twelve', which give no clue to their value, and then learn that 'thirteen' is not formed in the same way as 'twenty-three'. In languages such as Chinese, Japanese and Korean the numbers are far more regular: eleven is expressed as ten-one and twenty-three as two-ten-three. Studies comparing children who speak these languages with English-speaking children have found that the former often count accurately to ten at an earlier age and grasp place value more quickly.

Fingers provide another kind of support. Children who can show numbers on their fingers tend to do better at arithmetic some years later, and brain imaging studies suggest that finger movements and number processing draw on overlapping regions of the brain. Some teachers have discouraged finger counting, believing it a crutch that prevents children from calculating mentally. The evidence does not support this fear: children who use their fingers generally abandon the habit once they become fluent, and those who are forced to give it up too early may be disadvantaged.

What happens at home matters too. Researchers who recorded ordinary conversation in families found wide differences in the amount of number talk — counting stairs, comparing prices, noting how many spoonfuls — and these differences predicted children's number knowledge at school entry. Storybooks and board games that involve counting, moving a counter a fixed number of spaces and comparing totals appear to be particularly useful, because they combine the words with visible quantities and a reason to care about the answer.

What remains unclear is why some children struggle. Between three and seven per cent have a persistent and specific difficulty with number, known as dyscalculia, which is not explained by poor teaching or by low intelligence. Nor is it settled how much can be gained by training counting itself. Some intervention studies report improvements that persist; others find that the gains fade within a year or two, and that children who were behind remain behind. The link between early counting and later achievement is well established, but the direction of cause is harder to demonstrate.

Counting, then, is not a single skill but a series of small revolutions in understanding. The words come first, learned by repetition; comprehension follows months or years later, and then, for most children, arithmetic proper can begin.

In Britain, organised games became a central part of schooling in the second half of the nineteenth century, when boarding schools adopted team sports and credited them with building discipline, loyalty and the capacity to endure hardship. The idea travelled. Compulsory physical education is now standard in most countries, and in many systems a substantial part of the timetable is given over to competitive games rather than to exercise as such. Whether children should be compelled to take part in sport is therefore not a hypothetical question; it is settled policy in a great many schools. What is far less settled is whether the competition, rather than the movement, deserves the credit.

The most common justification is health. Children who are active are less likely to become overweight, and habits formed at school are thought to influence activity in adulthood. Yet the evidence that compulsory sport produces these effects is thinner than the confidence of the claims suggests. Studies that observe lessons directly have repeatedly found that pupils spend much of a games period standing still, waiting for a turn or listening to instructions, so the amount of vigorous movement is modest. Reviews that follow children into adulthood struggle to separate school sport from everything else in their lives, and several find little relationship between compulsory participation and later activity levels.

The second justification concerns character. Defenders of compulsory games argue that sport teaches children to lose gracefully, to cooperate, to control their tempers and to work hard at something they may not enjoy; they add that an adult world which is itself competitive requires young people to learn how to compete. These are attractive claims, and they appear in the prospectuses of schools that charge high fees. But the transfer of such lessons from the playing field to other areas of life is rarely demonstrated. What evidence exists suggests that character traits predict who takes up sport at least as much as participation shapes character, and that the benefits depend heavily on how the activity is taught.

Competition is a separate ingredient, and here the research is clearer. Studies of children's motivation consistently find that enjoyment and continued involvement depend on a sense of competence. When a child is continually measured against others and loses, the activity becomes a reminder of failure, and a child who expects to lose will often withdraw. Some critics go further and argue that competition should be removed from school sport altogether. The consequence of constant comparison is visible in participation data: involvement in organised sport rises through childhood and then falls sharply during early adolescence, and the decline is steepest among girls and among the less able — precisely the pupils that compulsory sport is meant to win over.

None of this means that competition is harmful in itself. For pupils who are good at it, contest is absorbing, and it would be absurd to deny them the chance to test themselves against others. Several studies suggest that competition can improve performance on straightforward tasks, and that learning to deal with defeat is a genuine benefit, provided the defeat is not humiliating and the sides are reasonably balanced. The mistake lies in assuming that because contest is valuable for some, it must be imposed on all.

There is a further difficulty that receives less attention. The costs of school sport are not shared equally. Kit, boots, travel to fixtures and membership of the clubs where the best players train all require money, and the pupils who benefit most from competitive teams are often those whose families already provide such advantages. Meanwhile, the argument that sport builds character is applied most insistently to children from poorer backgrounds, whose schools are least likely to have a full range of facilities. A policy that improves the prospects of the already fortunate and offers little to anyone else cannot be defended on the grounds that it is good for everybody.

Inclusion raises a sharper question. Pupils with physical disabilities are frequently excused from games rather than offered an activity they can do, and those whose bodies do not match the athletic ideal quickly learn that the gymnasium is a place of judgement. A pupil who is routinely chosen last learns something, but not what the advocates of team games intend. Such pupils may be far better served by other forms of movement — swimming, walking, dance, cycling — that carry the same physiological benefits without the public comparison. Where schools have widened the range of what counts as physical education, participation among the least active pupils has generally risen.

My own position is therefore this. Schools have strong grounds for making physical activity compulsory, since exercise is genuinely important and school is the one institution that can reach every child. They have much weaker grounds for making contest compulsory. The two are not inseparable: a department that runs competitive teams, offers non-competitive options and lets pupils choose between them satisfies both the health case and the arguments about motivation. What should be compulsory is movement; the chance to compete should be exactly that — a chance.