This edited article about the basilisk originally appeared in Look and Learn issue number 245 published on 24 September 1966.

Helmeted basilisk

It sometimes happens, although very rarely, that an elderly domestic hen may begin to grow wattles and to crow while still laying eggs. It may also happen that an elderly barnyard cockerel may lay a kind of egg. These things merely indicate that the birds are undergoing a change of sex in later life.

These things were noted by people living many centuries ago. They did not understand what was happening, so to them such events seemed miraculous, and they invented a legend to explain them. The legend was that the egg laid by an elderly cockerel would hatch and from it would come a rather terrifying creature which was half cockerel, half serpent. This cockerel with a serpent’s tail they called a cockatrice or basilisk.

The basilisk was the epitome of everything evil and was said to be so deadly that, if it looked at a man, he would drop dead. It was generally believed that there were basilisks all over the country, in hiding.

There was, however, an ingenious knight who had the idea that, if he made a suit of armour composed of mirrors, he could rid the country of basilisks because, whenever he confronted one of them, the basilisk would see its own image in his armour and would itself drop dead!

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This edited article about insects originally appeared in Look and Learn issue number 234 published on 9 July 1966.

Huge dragonfly-like insects lived in prehistoric forests

Two questions which will probably occur to anybody who looks at insects in all their variety are: “Why are there so many of them?” and “Where did they come from?”

Study of the lives of insects gives us an idea as to why there should be so many, for every different sort does a particular job which is not done by anything else in the area in which it lives. The large numbers of different species can be accounted for by the limited abilities of each one, for there are few “Jack-of-all-trades” among insects.

To discover how insects came into being is much more difficult, for in the animal kingdom are many related creatures. Spiders and crabs, for example, both have jointed legs attached to a hard skeleton outside the body. But these are cousins, not ancestors, to the insects.

We know what the ancestors may have looked like, however, through the discovery of a “living fossil” type of animal, known from many tropical parts of the world. This is called Peripatus, or Velvet Worm, because its body is covered by a huge number of tiny bumps which look like plush.

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This edited article about hibernation originally appeared in Look and Learn issue number 152 published on 12 December 1964.

A cutaway landscape showing hibernating animals by David Nockels

During the cold winter months you will sometimes find butterflies and moths hidden away behind curtains and pictures or in corners of rooms that are little used. They look quite dead, but if you move them carefully to some place that is warm you will see them gradually fluttering back into life.

In the same way, you may find a hedgehog buried in the leaves at the bottom of a ditch or rolled up in a ball under a garden shed. If you have a pet tortoise it will disappear in winter – unless you come across it in some sheltered spot drawn into its shell and to all appearance lifeless.

These are only a few of the many creatures who escape the cold of winter and manage without food by going into the deep sleep called hibernation.

The term “hibernation” comes from the Latin word hibernatus, meaning “winter quarters.” And that is exactly what hibernating creatures do: they go into winter quarters and sleep soundly until spring brings warmth again.

In countries of northern and western Europe and North America many animals find their supply of food cut off in winter and would starve. So they go into a long deep slumber, and keep themselves alive on the fat that has accumulated in their bodies when they were able to feed in the summer and autumn.

Unlike the birds, which can fly for thousands of miles to warmer lands where food is plentiful, most animals cannot travel long distances to places in search of food.

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This edited article about the manatee originally appeared in Look and Learn issue number 146 published on 31 October 1964.

Mermaid or manatee?

When nature designed the manatee she was not quite sure whether it was going to be a fish or a land-living animal. For although this queer creature spends all its life in the water it feeds by browsing on vegetation.

At one time zoologists thought it was a close but small relative of the whale. It has a fish-shaped body, forelimbs like paddles and the flat, horizontal tail of the whale.

But there the resemblance ends. The manatee has teeth, whereas the whale has none. It does not blow like a whale, but comes to the surface of the water to breathe just as a land animal would do. And even more unlike whales, it is not a deep-sea creature, seldom venturing far from the coast or the mouths of rivers.

Actually, the creature is closely-related to herbivorous (plant-eating) land animals such as the cow. It is thought that the ancestors of the manatee were land animals which through millions of years became specially adapted for feeding on underwater vegetation.

When the manatee periodically raises its head out of the water to breathe, it has a strangely human appearance. This probably gave rise to the legend of the mermaid. For that reason its Latin zoological name is Sirenia, from the Latin word, sirene, meaning “sea nymph.”

There are three species. One is native to South America, one to North America, and the third to the coast of West Africa. No adult species is more than eight feet long and all have a smooth, hairless skin.

The forelimbs or flippers are oval shaped and have three nails at the tips.

Manatees’ mouths are specially designed for cutting great swathes of underwater vegetation.

The upper lip consists of two bristly pads by means of which the weed is sucked into the mouth, where it is squeezed and pressed by horny plates on the palate. The process of chewing is helped by eleven pairs of cheek teeth in each jaw.

These teeth are constantly being renewed. They are arranged in such a way that as the front ones are shed their places are filled by teeth from behind. As the first teeth are used up before the last of the series has fully developed, only six teeth are functioning at the same time.

Manatees eat such enormous quantities of water weeds that in 1962 their appetites were exploited to clear thick growths of weeds which were choking the drainage ditches and canals in Georgetown, British Guiana.

A force of 70 of the animals was taken on the strength of the British Guiana Department of Drainage and Irrigation. When they were put to work in a badly-choked canal they relentlessly cut a swathe through the vegetation, so enabling the water to flow more freely.

When they reached the end of the canal the vegetation had grown again behind them. So the manatees turned and mowed it down again.

Travelling backwards and forwards along the canals, the aquatic lawnmowers can in a few hours clear an amount of weeds which it would take a gang of men several days to do. On one occasion two large ponds each covering an area of nearly 4,000 square yards and hopelessly choked with water weeds were cleared by three industrious manatees in a week.

Incidentally, the British Guiana manatees are the first marine animals that have been successfully domesticated by man and made to work for him.

This edited article about amoeba originally appeared in Look and Learn issue number 118 published on 18 April 1964.

Crustacea with the distinctive cyclops (centre)

When you look in a pond it seems to be alive with sticklebacks and minnows, tadpoles and newts, water beetles and snails. They seem very tiny indeed and there are a lot of them.

But if you examine a drop of water from the pond through a microscope you see a world of creatures tinier than the smallest fish or insect.

In this crowded, busy little world every speck of life keeps its microscopic body alive by feeding and by taking in oxygen and giving out carbon dioxide to “breathe” as do fish and land animals.

Every living thing in the drop of pond water is continually on the move. Some move slowly as though feeling their way about. Others cross and re-cross and dart backwards and forwards in a flurry of activity. You might be at the top of a skyscraper watching a street during the rush hour instead of looking at a drop of water.

Smallest of all these microscopic creatures are the amoeba, which are the most simple forms of animal life. There are several kinds of amoeba but each consists of a single speck of jelly-like substance which must be magnified about a hundred times by the microscope to be seen.

Some amoeba propel themselves through the water by means of minute, hair-like threads called cilia. These are constantly vibrating and set up currents in the water to push the midgets along. Other amoeba move about by pushing out from their bodies microscopic projections of jelly called pseudopodia, which cause them to glide or flow across the surface of the water.

Then there is the paramoecium, sometimes called the slipper animalcule because of its shape. A procession of two hundred of them marching in single file would be less than an inch long. Despite its small size, the paramoecium is covered with a kind of shell called a pellicle.

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This edited article about nature originally appeared in Look and Learn issue number 807 published on 2nd July 1977.

Bats

Cuttlefish, trapdoor spiders, bats and glow-worms are only some of the members of the animal kingdom which “discovered” scientific facts long before Man

Powered by its jet engines, a Concorde sweeps several kilometres high across the Atlantic at twice the speed of sound (about 2,240 km per hour at a height of approximately 10 kilometres above sea level). Concorde is one of the greatest achievements in modern transport, but the principle of the engines that give the aircraft its fantastic speed is older than man himself.

Countless millions of years ago, a group of creatures called cephalopods were jet-propelling themselves through now forgotten seas. The most common cephalopods today are the cuttlefish.

Next time you visit a large aquarium or marine zoo look out for a cuttlefish. You will notice that, though it manoeuvres with its fins, when it is surprised it appears to be jet-propelled and moves through the water in a series of darting motions.

The secret of the cuttlefish’s jet propulsion is that it sucks water into its body through a wide opening in its head, called the mantle. As the water is sucked in, muscles in the mantle contract, so reducing the space for the water.

Contracting the muscles increases the pressure at which the water is held in the mantle. Increasing the pressure on the water causes it to squirt out at high speed through a narrow opening in the mantle. This opening is called the syphon. In fact the action is rather like squirting soda water from a syphon.

The cuttlefish’s motion is based on the same principle as that of rocket propulsion. As expanding gases shoot from the tail of a rocket, the force known as reaction causes the rocket itself to move forward. The cuttlefish’s water jet produces the same effect.

Turbo-jet engines that power aircraft work in exactly the same way. The only difference is that the jet engine uses a stream of hot and expanding gases.

Air is sucked in through the front of the engine and passes to a device called a compressor. The compressor then forces the air at increased pressure into a space called the combustion chamber. In the combustion chamber the air is mixed with a highly inflammable fuel and becomes very hot.

Heating the air and other gases makes them expand. As the gases expand, they struggle for more space in the combustion chamber and try to escape. The only escape route is through a nozzle at the rear of the engine.

Just as the cuttlefish is moved by the jet of high-pressure water forced out of its body, so the aircraft travels forward because of the high-pressure gases streaming from the rear of the engine.

Jet propulsion is just one of scores of devices which we use every day but which were really in use by animals before man ever thought of them.

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This edited article about Darwin in Australia originally appeared in Look and Learn issue number 757 published on 17th July 1976.

Charles Darwin on the Galapagos Islands by Andrew Howat

It was on Christmas Day, 1974 that a hurricane named Tracy hit the northern coast of Australia and virtually wiped out the 27 square mile city of Darwin, chief port and administrative centre of the Northern Territory. The rest of the world was shocked at the extent of the damage, although most people had to reach for a map in order to discover exactly where Darwin was.

Gone were the 1930s when it had been well known as the goal of daring round-the-world flyers, even though the name was familiar. Probably, people surmised, it had been named after Charles Darwin. But had the great British naturalist ever been as far afield as Australia? The doubts were not surprising, for few associated photographs of a bearded 80 year old with the young man of 22 who had made one of the most significant voyages of all time. This was a voyage to the New World in 1831.

With the help of an artist, Darwin’s task was to record and obtain specimens of the plant and animal life of the countries visited, and for the next five years he worked with enthusiasm as the Beagle, on which he was travelling, slowly made her way along the coasts of South America and onwards to lands that were still mentioned very hazily in even the best geography books. Tahiti, the Maldives, Keeling Island, Tasmania, New Zealand, Australia, Darwin saw them all, and as he noted, collected and catalogued his specimens a new and extraordinary conviction began to form in his mind.

It had begun to grow after his visit to the Galapagos Islands, where he had light-heartedly ridden on the back of a giant tortoise and faithfully logged its speed as 4 miles per day. The islands abounded in a number of different types of finch, each specially equipped by nature for a particular task. On one island the birds had strong beaks for cracking the local nuts, on another they had small beaks for catching insects. There were woodpecker-like finches, and fruit-eating finches and even one that dug grubs from holes with a cactus spine. It seemed to Darwin reasonable to suppose that they had evolved, and adapted their shape over the centuries in order to suit their surroundings.

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This edited article about bird migration originally appeared in Look and Learn issue number 741 published on 27 March 1976.

Migrating swallows by A Oxenham

The radar operator stared in horror at the screen in front of him. The ‘blips’, or echoes of light on the radar, indicated a vast number of enemy planes heading straight for Britain, possibly on a massive bombing raid!

An air-raid warning was immediately given, and thousands of war-time Britons muttered unkind things about the Germans before hurrying to their shelters or into the Underground stations.

Yet no bombs fell that night, no aircraft were picked up by the probing searchlights, and before long, the “all-clear” siren filled the air with its welcome wail.

These false alarms happened many times before it was realised that the mysterious aircraft were in fact birds.

Since then, radar has provided much valuable information about the heights birds fly at, their course and their speed, adding to our knowledge about the annual movement of birds that takes place every year without fail and which has been taking place every year since man has been around to observe it.

But although we know where the birds go and we know why they go, we still do not fully understand how they are able to find their way hundreds, even thousands, of miles across strange lands and seas until they reach their destination. And we certainly do not know how the birds recognise this destination when they reach it.

Take the swallows, for instance. During the spring and summer we see them wheeling and darting above our houses and fields, ever on the look-out for insects. But as autumn approaches, they turn their faces south.

Over the Channel they head, right across France, throughout the length of Italy and over the Mediterranean. Still they travel on, down the Nile into the heart of Africa until they reach the very southern tip, Cape Town.

But as the sun begins to gather strength in Britain, as the first buds begin to appear on the trees, the swallows make the return journey, often going back to the very same farm, the very same barn, where they had nested the previous year.

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This edited article about human skin originally appeared in Look and Learn issue number 734 published on 7 February 1976.

Skin is perpetually renewed but its protective surface can easily be broken, as in the case of a mosquito bite. Picture by R B Davis

In spite of the skin’s tissue-like thinness, it is the largest and heaviest organ of the human body. The skin of a fully-grown person covers an area of over 3,000 square inches and has a total weight of nearly four pounds. That is more than the liver weighs.

Every square inch of your skin contains hundreds of nerve endings, several feet of blood vessels, many thousands of cells and hundreds of sweat glands. The thickness of the skin varies from 1/6th of an inch to 1/250th of an inch. It is thickest on those parts of the body which are subject to the most “wear”, such as the soles of the hands and feet.

There are two layers of skin, the epidermis or top layer and the dermis, which lies immediately under the epidermis. The epidermis is the skin that flakes or peels off when you get sunburned.

When a piece of the epidermis is examined under a powerful microscope, it is seen to be made up of rows of flattened cells piled upon one another like the bricks in a wall. The outer layer of these cells, which make up the surface of the skin, are constantly dying and being worn away. And as fast as they are worn away they are replaced by new cells pushed up from below.

It is because of the continual renewal of the skin’s worn-out cells that a healthy skin looks clean and fresh over a period of years. Skin that has been damaged or destroyed by minor bruises, cuts or burns is soon replaced. Often the replacement is so perfect that no scar remains.

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This edited article about the mammoth originally appeared in Look and Learn issue number 718 published on 18 October 1975.

Mammoths lived in the Ice Age which explains why the remains of some of them have been perfectly preserved, by Angus McBride

The mammoth was an animal well suited to the Ice Age in which it lived. It had a shaggy coat of reddish-black hair and a thick layer of fat under the skin to protect it from the cold. Complete mammoths have been found in the frozen wastes of Siberia and Alaska – still wearing the remnants of their hairy coats. The contents of the beasts’ stomachs were also intact, giving scientists evidence of their diet.