Reading — 2026 Jan–Apr Recall Set 37

The Maori are the indigenous people of the islands of New Zealand. Their traditional medicine, which is believed to date back as far as the 13th century, was a system of healing that was passed down through the generations orally. It comprised diverse practices and placed an emphasis on the spiritual dimension of health. Its practice included remedies made from herbs, and physical therapies such as massage to relieve discomfort in the muscles and bones. Maori systems for treating illness were well developed before Europeans arrived in New Zealand in the late 1700s: they had quite detailed knowledge of anatomy and recognition of the healing properties of various plants. When Europeans first visited New Zealand, the average age of death for Maori adults was around 30. However, apart from this, the people were fit and healthy, and troubled by few diseases. Illness was often seen as spiritually based. Maori saw themselves as guardians of the earth, and the focus of their existence was to remain at one with the natural and supernatural world. Rather than a medical problem, sickness was often viewed as a symptom of disharmony with nature. In Maori culture, illnesses were divided into diseases of the gods (mate atua) and physical diseases (mate tangata). Diseases sent by the gods were often attributed to attacks by evil spirits, because the person had broken a religious rule. For instance, for Maori, places where people had died, or places where their ancestors were buried were sacred, so if someone took food from a river where someone had died, or took a stick from a tree that had held their ancestor's bones and placed it on a cooking fire, it was believed that the gods could punish them for their disrespectful acts by making them sick. More than 200 plants were used medicinally by Maori. The leaves of the flax plant were used to treat skin infections and food poisoning, and the hard part of the leaf was also used as a splint or brace for broken bones and injured backs. Flax fibers were used along with a sharpened stick to sew up bad cuts. The bark and leaves of the pepper tree were used to heal cuts, wounds and stomach pain. People who had toothache were instructed to chew the leaves of this same tree, and this was found to be of considerable benefit. The pepper tree was also used in vapor baths to treat people with painful joints. Colonization by Europeans in the 1800s had a significant effect on traditional Maori healing. Europeans brought many new diseases with them which Maori healers had limited ability to combat. Though Western medicine was also relatively ineffectual at the time, this failure still strongly affected Maori confidence in their healers. Some western missionaries attributed the spread of disease to the fact the Maori did not believe in Christianity, and as Maori healers appeared powerless, many Maori accepted this explanation and turned to Christianity. Over time the schools of higher learning which had trained healers started to close and the tradition of the Maori healer declined. From the late 20th century, there was renewed Maori interest in their traditional medicine. This was due to several factors. There was a resurgence of all aspects of Maori culture in New Zealand. Furthermore, people started to be less trusting of Western medicine—statistics from the 1970s came out revealing that Maori health continued to be poorer than that of other New Zealanders. There were also problems with access to health care for Maori. Additionally, there was and still is today a perceived lack of a spiritual dimension in Western health services. Although Maori today largely accept Western concepts of health and illness, and use the mainstream health system, there is significant demand for traditional medicine. This is true for unusual illnesses, or those that fail to respond to standard medical treatment, but also for common ailments such as the cold and influenza. Today's healers differ significantly from those of old times. Training is highly variable, usually informal, and often less tribally bound than the rigorous education of the traditional houses of higher learning. Many modern healers work in urban clinics, some alongside mainstream health professionals. They experiment, incorporating knowledge from Western and other medical systems. As a result, their modern day work has no standard system of diagnosis or widespread agreement about treatments. Despite this, many healers are recognized as having knowledge and ability that has been passed down from their ancestors. The Maori language is also seen as important by many of those receiving treatment.

A Even though crocodiles have existed for 200 million years, they’re anything but primitive. As crocodiles’ ancestors, crocodilia came to adapt to an aquatic lifestyle. When most of the other contemporary reptiles went extinct, crocodiles were able to make it because their bodies changed and they adapted better to the climate. They witnessed the rise and fall of the dinosaurs, which once ruled the planet, and even the 65 million years of alleged mammalian dominance didn’t wipe them off. Nowadays, the crocodiles and alligators are not that different from their prehistoric ancestors, which proves that they were (and still are) incredibly adaptive. B The first crocodile-like ancestors came into existence approximately 230 million years ago, and they had many of the features which make crocodiles natural and perfect stealth hunters: streamlined body, long tail, protective armour and long jaws. They are born with four short, webbed legs, but this does not mean that their capacity to move on the ground should ever be underestimated. When they move, they are so fast that you won’t even have any chance to try making the same mistake again by getting too close, especially when they’re hunting. C Like other reptiles, crocodiles are poikilothermal animals (commonly known as coldblooded, whose body temperature changes with that of the surroundings) and consequently, require exposure to sunlight regularly to raise body temperature. When it is too hot, they would rather stay in water or shade. Compared with mammals and birds, crocodiles have a slower metabolism, which makes them less vulnerable to food shortage. In the most extreme case, a crocodile can slow its metabolism down even further, to the point that it would survive without food for a whole year, enabling them to outlive mammals in relatively volatile environments. D Crocodiles have a highly efficient way to catch prey. The prey rarely realises there might be a crocodile under the water because the crocodile makes a move without any noise or great vibration when spotting its prey. It only keeps its eyes above the water level. As soon as it feels close enough to the victim, it jerks out of the water with its wide open jaws. Crocodiles are successful because they are capable of switching feeding methods. It chases after fish and snatches birds at the water surface, hides in the waterside bushes in anticipation of a gazelle, and when the chance to ambush presents itself, the crocodile dashes forward, knocks the animal out with its powerful tail and then drags the prey into the water to drown. E In many crocodilian habitats, the hot season brings drought that dries up their hunting grounds, leaving it harder for them to regulate body temperatures. This actually allowed reptiles to rule. For instance, many crocodiles can protect themselves by digging holes and covering themselves in mud, waiting for months without consuming any food or water until the rains finally return. They transform into a quiescent state called aestivation. F The majority of crocodilia are thought to go into aestivation during the dry season. In a six-year study by Kennett and Christian, the King Crocodiles, a species of Australian freshwater crocodiles, spent nearly four months a year underground without access to water resources. Doubly labelled water was applied to detect field metabolic rates and water flux, and during some years, plasma fluid samples were taken once a month to keep track of the effects of aestivation regarding the accumulation of nitrogenous wastes and electrolyte concentrations. G The study discovered that the crocodiles’ metabolic engines function slowly, creating waste and exhausting water and fat reserves. Waste is stored in the urine, becoming more and more concentrated. Nevertheless, the concentration of waste products in blood doesn’t fluctuate much, allowing the crocodiles to carry on their normal functions. Besides, even though the crocodiles lost water reserves and body weight when underground, the losses were proportional; upon emerging, the aestivating animals had no dehydration and displayed no other harmful effects such as a slowed-down growth rate. The two researchers reckon that this capacity of crocodiles to get themselves through the harsh times and the long starvation periods is sure to be the answer to the crocodilian line’s survival throughout history.

Scientists have long known that the surface of the tongue is covered with taste buds: onion-shaped bundles of cells that stand guard for the digestive system. Long before our modern world of supermarkets and restaurants, taste buds served as a crucial tool to maintain the daily existence of our ancestors. The bitter flavour of a wild almond told a prehistoric human foraging in African forests that the nut was poisonous, and they should spit it out. A sweet fruit, though, was safe to consume, and full of energy from carbohydrates. The presence of lions and other man-eating predators also added urgency to meal choices. 'If the thing didn't taste good, you might decide it's not worth it to be out in the open and at risk,' says Steve Miller, a taste researcher at the University of Maryland School of Medicine. Much of what we 'taste' in everyday life is actually the work of our nose. The tongue can distinguish only five basic flavour sensations – sweet, sour, bitter, salt and umami, the 'savoury' taste of meat and cheese which indicates protein. Sour taste comes from acidic compounds, and, like bitter taste, it can be a sign to leave decomposing meat or vegetables. Unpleasant tartness in unripe fruits comes from too much citric acid. This is how a tree or shrub keeps hungry diners at bay until its seeds are mature enough to travel – via the diner's digestive system – to a new home. Unlike animals, humans have acquired a taste for tartness. In the case of the Japanese pickle called ‘umeboshi’, the plums are harvested when still green and sour, before the tree fills them with sugar and turns them into a tantalising snack for birds and animals. Sour cream, yoghurt, lemonade, gorgonzola cheese, the German fermented cabbage ‘sauerkraut’ and other tart treats are eaten every day by millions of people. Only a decade ago, popular myth held that separate areas of the tongue were responsible for each taste. Referred to as the ‘mouth map’, the concept probably originated with a German text mistranslated into English at the beginning of the 20th century. As recently as 1996, ‘mouth map’ diagrams still appeared in university neuroscience textbooks. By the late 1990s, however, scientists had learned enough about molecular biology to turn their attention seriously to taste. They had discovered that thousands of taste buds cover the tongue, each containing 50 to 100 taste cells. Each cell has two poles: one end covered with taste receptors projecting from the tongue's surface, and one end inside the tongue that connects to the brain via nerves. When a person bites into a lemon, acidic molecules from the food bump into acid-sensitive taste receptors, activating a taste cell, which sends a ‘sour’ message to the brain. The details of this process were long a matter of debate. In line with the ‘mouth map’ concept, some scientists believed that the taste buds in different areas of the tongue were filled with cells of only one type: the tip with sweet-sensing cells, the back with bitter-sensing cells, and so on. Others were not convinced and further suggested the location of cells was not an issue because each cell could sense all five tastes. However, no one had identified any of the taste receptors, so which cells responded to which tastes was unknown. Charles Zanker, professor of biology at the University of California, San Diego, and others set out to solve this problem with a variety of biological techniques, including engineering mutant mice that lacked certain receptors and could not taste certain tastes. They eventually isolated the first taste receptors – those for bitter and sweet. Each taste cell, they found, is covered with receptors for only one taste. A sweet cell, for example, is only turned on by sweet molecules because it only has sweet receptors. This dispelled the notion that all cells could sense all tastes. The scientists also assembled more evidence against the 'mouth map' myth when they found that each taste bud contains a full complement of taste cells. 'There are areas of emphasis,' Miller says, 'but there are not these absolutely divided areas.' Over time, the researchers identified the receptors for sweet, bitter and umami. But until recently, salt and sour receptors remained elusive. After eight years of this new wave of research into taste, a team led by Hideki Matsunami from Duke University in North Carolina, and Zanker's separate group of Californian scientists, simultaneously published that they had finally found the tongue's tart sensors. This breakthrough has answered some long-standing questions about the tongue's geography. One surprising finding was that the sour-taste receptors on the tongue are also found in the spinal cord, where they probably monitor the acidity of cerebrospinal fluid. Similarly, sweet and bitter taste receptors have been found in the intestinal tract. Taken as a whole, the identification of various key taste receptors illuminates a link between the mouth and the brain. It also provides new targets for research. In the past, artificial flavourings were often chance discoveries, made when chemists accidentally tasted a substance, but now experts hope that knowing the identities of taste receptors will allow a more methodical approach to be taken towards developing these additives. New molecules might even be developed to cling to sour taste receptors and block the unpalatable taste of medicines. The finding may also explain how tongues, like fingerprints, are unique, making some people sensitive and others numb to certain tastes.