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Subject: ‘Dinosaurs’

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Dinosaurs were simply too large to survive the forces of nature and evolution

Posted in Animals, Dinosaurs, Nature, Prehistory on Tuesday, 17 September 2013

This edited article about Prehistoric animals originally appeared in Look and Learn issue number 404 published on 11 October 1969.

Anatosaurus, picture, image, illustration

Anatosaurus, the duck-billed dinosaur

The one thing to remember about the monsters of long ago is that they really were monsters. Compared with modern animals they were strangely formed and nearly all of them were enormous.

The most familiar of these monsters are dinosaurs, orders of reptiles, which lived on Earth many years before man arrived.

Tyrannosaurus belonged to the suborder Theropoda and, standing on its hind legs, was probably about 20 ft. high. From head to tail, it measured around 50 ft. It had very sharp teeth, about six inches long, and unlike some dinosaurs was flesh-eating.

In fact, as it and its kind roamed the Earth, hunting for the smaller animals which made up their food, great must have been the clamour that arose from their battles and the ground must have shaken and trembled at their approach.

Rather strangely, however, although tyrannosaurus had very powerful, muscular hind limbs, its forelimbs were tiny and virtually useless.

Allosaurus probably lived rather earlier in time than tyrannosaurus but this also was a formidable beast. There is a specimen in the American Museum of Natural History which is 34 ft. long.

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The 100 million-year-old mystery: what happened to the dinosaurs?

Posted in Animals, Dinosaurs, Mystery, Nature, Prehistory on Thursday, 7 June 2012

This edited article about dinosaurs originally appeared in Look and Learn issue number 721 published on 8 November 1975.

Dinosaur skeleton, picture, image, illustration

Children looking at the skeleton of an Iguanadon by Roger Payne

Reptiles ruled the earth, the sea and the air for over 100 million years. Then about 70 million years ago they disappeared from the world almost completely, leaving only the fairly small groups which survive today – snakes, lizards, turtles and crocodiles.

Why and how such a large, varied and long-dominant group became virtually extinct is a question which still puzzles scientists. Was it simply racial old age or were there other reasons?

One theory is that climatic changes at the time meant changing vegetation, making it increasingly difficult for the herbivorous dinosaurs to find food. These creatures, therefore, gradually died out. With their prey gone, the meat eaters also starved to death.

Another theory also links the disappearance of the dinosaurs with the climate. As the reptiles were cold-blooded they were unable to cope physically with a changing climate.

Yet another idea is that the small, egg-eating mammals which had developed were responsible: the mammals stole and ate the dinosaur eggs, therefore less and less dinosaurs were born.

Perhaps there were a number of factors which contributed to their extinction.

Whatever the reason, however, they certainly did vanish and their going made way for the rise of the mammals.

The Age of Reptiles peaked with the dinosaurs

Posted in Animals, Dinosaurs, Nature, Prehistory on Thursday, 7 June 2012

This edited article about dinosaurs originally appeared in Look and Learn issue number 721 published on 8 November 1975.

Dinosaurs, picture, image, illustration

Dinosaurs by David Nockels

The best known creatures from the Age of Reptiles are the dinosaurs (‘terrible lizards’). The word ‘dinosaur’ usually conjures up a picture of a huge, ponderous and rather stupid creature, like brontosaurus, or, a 20 foot (6m) tall, meat-eating tyrannosaurus with sharp claws and fearsome teeth for devouring its victims.

In fact dinosaurs came in all shapes and sizes. Although many were large and slow, others were no bigger than a chicken and could move very fast. And some of the most frightening-looking were in fact peaceful plant-eaters which had developed heavy armour plating to protect them from predators.

Dinosaurs belonged to one of the largest groups of reptiles, the archosaurs. The earliest archosaurs were the thecodonts’ (‘socket-toothed’) of the Triassic period, an order of carnivorous reptiles. Thecodonts were an extremely important group as they were the ancestors of the crocodiles, the flying reptiles (pterosaurs) and the first birds as well as the two distinct types of dinosaur – the saurischia (‘lizard-hipped’) and the ornithischia (‘bird-hipped’).

The carnivorous tyrannosaurus – the largest land-dwelling meat eater of all time – and the gentle plant eater, brontosaurus, both belonged to the lizard-hipped group of dinosaurs.

All the members of the ornithischia were plant eaters. This group includes the large, horned triceratops, the stegosaurus and the iguandon.

Both of the dinosuar groups were more or less equally divided into quadrupeds and bipeds.

The evolution of Earth’s first mammals eventually brought placental birth

Posted in Animals, Dinosaurs, Nature, Prehistory on Thursday, 7 June 2012

This edited article about prehistoric mammals originally appeared in Look and Learn issue number 720 published on 1 November 1975.

Protoceratops eggs, picture, image, illustration

Reptiles, like the dinosaurs before them , lay their eggs and abandon them; here we see the Protoceratops young hatching from their unattended dinosaur eggs

All mammals are thought to have descended from the carnivorous reptile, therapsid which lived in Permian and Triassic times. This had upright legs instead of splayed-out reptilian ones and a wide variety of teeth. In the Jurassic the first true mammal appeared, the tiny, shrew-like triconodon.

About 70 million years ago the Cenozoic (or New Life) era began with the Palaeocene; the climate was mild and the vegetation tropical. The small mammals which had lived in the shadow of the dinosaurs were ready to replace them as the dominant form of life.

Mammals were better equipped for survival than reptiles. They were warm-blooded and could cope with changing climatic conditions. They developed larger brains than reptiles. Thirdly, although early mammals were egg-layers, later marsupials (pouched mammals) and then placental mammals, which gave birth to fully developed live babies, evolved. Marsupials and placental mammals care for their young until they can fend for themselves, unlike reptiles which lay their eggs on the ground and then abandon them.

Reptiles ruled the earth for 100 million years

Posted in Animals, Dinosaurs, Nature, Prehistory on Thursday, 7 June 2012

This edited article about prehistoric reptiles originally appeared in Look and Learn issue number 720 published on 1 November 1975.

The dimetrodon, picture, image, illustration

The Dimetrodon

Reptiles replaced amphibians as the dominant life form and their reign lasted for more than 100 million years.

During the Permian era an interesting group of reptiles was the pelycosaurs (mammal-like reptiles), the best known of which was the dimetrodon. This 10 ft. (3 m.) long carnivore was most notable for its sail-like fin, formed by a row of thin bones covered with skin. This is thought to have acted as a heat receptor to keep the creature’s blood at the correct temperature.

During the Triassic era a group of flying reptiles, called pterosaurs, evolved. Their wings were folds of leathery skin stretched between their short back legs and the tips of their long front limbs. Half the wing’s length was supported by a long wrist bone and fourth digit, the other three ‘fingers’ being claws used for climbing and hanging from a perch. Their bodies were thinly covered with hair and, like birds, they had hollow bones filled with air. They ranged in size from as small as a sparrow to the huge pteranodon with a 27 ft. (8.1 m.) wing-span.

Other reptiles took to the sea.

The principal groups were the streamlined ichthyosaurs and the plesiosaurs. The latter had paddle-shaped limbs with which they ‘rowed’ themselves along in the water.

Fossils testify to the age of the giant reptile

Posted in Animals, Biology, Dinosaurs, Prehistory on Friday, 13 April 2012

This edited article about dinosaurs originally appeared in Look and Learn issue number 688 published on 22 March 1975.

Tyrannosaurus rex, picture, image, illustration

Tyrannosaurus Rex attacking a Styracosaurus by William Francis Phillipps

A hungry two-legged reptile crept along the sands of the Gobi desert in Central Asia. As it snuffled in the sand, this creature, named an Oviraptor (or egg-stealer), came upon just the meal he was looking for – a nest of eggs.

The eggs were in varying stages of development and some had inside them the partly-formed young of a horned reptile called a Protoceratops.

It must have been a great find for the Oviraptor, but he did not have long to enjoy it. A violent sandstorm arose and buried the egg-stealer and his plunder.

All this is supposition. But what is fact is that millions of years later, in the 1920s, scientists found the nest, and several others. Inside them were the fossilised remains of the baby dinosaurs in various stages of growth, from newly hatched young to adults measuring 1.5  metres to over two metres. And inside the eggs were found preserved embryos.

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Diplodocus the herbivore

Posted in Animals, Dinosaurs, Prehistory on Wednesday, 15 June 2011

This edited article about dinosaurs originally appeared in Look and Learn issue number 969 published on 4 October 1980.

diplodocus, picture, image, illustration

The Diplodocus sustained its huge bulk on a diet of plants, by Roger Payne

If you are lucky enough to live within easy reach of London, or if you should visit the capital on holiday, you would enjoy a visit to the Museum of Natural History in Kensington. There you would find a whole section on prehistoric animals, and one of the largest reconstructed dinosaur skeletons in the world. It is of an animal which is known as diplodocus (pronounced diplo-docus) and its total length is almost 27 metres, but most of this is made up of its neck and tail.

Diplodocus was a plant-eater – a herbivore, and despite its great overall length it weighed a mere ten tonnes when it was alive about 130 million years ago. Also known as sauropods, these huge animals are believed to have spent only part of their time in the shallow water round the edges of lakes or rivers. They probably rested there from the heat of the day, and foraged for food on dry land.

It is hard to see how these massive, and probably slow-moving, dinosaurs were able to defend themselves against predators, except perhaps by swimming or moving out into deeper water. With their exceptionally long necks they would certainly be able to see danger approaching when it was still some distance away.

One herbivorous dinosaur which certainly could defend itself against almost any attacker was known as triceratops. It was not alive at the same time as diplodocus, but millions of years later. Triceratops was certainly a fearsome-looking animal which in itself was probably enough to deter most predators. It was also fairly large as dinosaurs go, with a length of over seven metres, and a weight of around eight tonnes. Skeletons in a fossilised state have been found in North America and it appears that triceratops existed in quite large herds towards the end of the Mesozoic era.

Its principal defence was the battery of horns round its large, heavily-boned head. It had a big horn above each eye, and a smaller one on its nose not unlike that of the present day rhinoceros. It also had a “frill” of bone which reached back to protect its shoulders.

Triceratops also had enormously powerful jaws. The muscles that closed them were more than one metre in length, and, as with other dinosaurs, its teeth were replaced as they wore out.

Fossils of these horned creatures have been found in the north-east of Asia, and in the western area of North America. Several varieties developed, some with a short “frilled” bone collar and others with a longer collar. One even had horns growing horizontally outwards from its cheeks.

Tyrannosaurus Rex

Posted in Animals, Dinosaurs, Prehistory on Tuesday, 14 June 2011

This edited article about dinosaurs originally appeared in Look and Learn issue number 968 published on 27 September 1980.

T. Rex, picture, image, illustration

The Tyrannosaurus Rex attacks

If ever a writer of horror stories wanted to frighten his readers, or a film-producer wanted to bring a spine-chilling monster into his pictures, the chances are that both of them might choose to base their plots on what has been described by scientists as the largest flesh-eating animal ever to walk the earth – the dinosaur known as tyrannosaurus rex.

This fearsome looking animal had a total length of almost 15 metres from the top of its head to the tip of its tail. When it reared up to full height, its huge head towered five metres above the ground, and it could easily have looked over the top of a double-decker bus. Its probable weight was at least eight tonnes – more than double the weight of the average African elephant – and its skull was over a metre long.

Although it probably could not run as fast as the allosaurus, it could certainly move fast enough to catch some of the lumbering plant-eating dinosaurs on which it undoubtedly preyed. Fossilised remains of its footprints have been found, and measurements show that its stride was little more than one metre, although this would probably have increased when this huge animal began to run.

This monster of the Mesozoic era had teeth which resembled serrated daggers and most of them were 15 cms long.

One aspect of tyrannosaurus has puzzled zoologists. From fossilised remains found in North America it is apparent that it had only short, stunted forelimbs, which were a mere 75 cms long. Although there are one or two theories about this – some scientists think they were used to aid it in getting to its feet after resting – no one can be sure why they were so much smaller than its other limbs.

Tyrannosaurus was alive right up to the end of what is called the Cretaceous period at the end of the Mesozoic era, when all the dinosaurs began mysteriously to disappear.

Another dinosaur which lived at the same time, called phobosuchus, was a distant ancestor of the present day crocodile. It lived in swampy river areas, and probably lay in wait for smaller land-based dinosaurs which came down to drink the water.

This king-sized crocodile was 16 metres long – compared with just under six metres for the larger present day specimens – and its head alone was two metres in length. An encounter between one of these waterborne reptiles and tyrannosaurus would have been a battle royal indeed!