|
|
|
| Sunday, 2 October 2005 |
 |
|
 |
Junior Observer |  |
| News Business Features Editorial
|
When dinosaurs ruled the world... Their diet
Even though dinosaurs lived millions of years ago, man continues to 'dig' around for more and more information about these prehistoric creatures. Last week we touched base with these gigantic animals, by exploring the various theories put forward by scientists as to their disappearance, and also looked at many other interesting facts about them. This week too we continue with our journey into the fascinating world of dinosaurs... We now know that there were two types of dinosaurs, the plant-eaters and the meat- eaters. The herbivores or the plant-eating dinosaurs which were also known as sauropods came in all shapes and sizes. Leaves were the main diet of many sauropods. It is believed that like the giraffe, Brachiosaurus used its long neck to graze on leafy treetops, while the Psittacosaurus probably snipped leaves off with its bird-like beak, then sliced them into smaller bits with its scissor-like teeth. How do experts know what these animals ate, you may wonder. Well, as most plant-eating dinosaurs too had teeth, they can tell what food they ate by looking at tooth fossils found from around the world. For instance, it has been revealed that a dino named Lufengosaurus, an early sauropod, had many small peg-like teeth with jagged edges. These were great for nipping on soft leaves but no use for chewing. So, the food was probably swallowed whole. As grasses did not develop on Earth until 25 million years after the dinosaurs died out, these prehistoric animals' food comprised various other plants such as leaves, pine needles and juicy shoots. Hadrosaurs are dinos with crests, frills and inflatable air sacs on their heads, and Saurolophus which belonged to this group is believed to have eaten leaves from flowering plants and crunchy pine cones. It may have chopped off the leaves with its horny beak and then chewed them with its flat, back teeth. Shunosaurus had peg-like teeth to munch on leaves and juicy shoots while the horned Triceratops sliced up tough ferns and horsetails with their sharp beaks and teeth. Would you believe that a sauropod's huge body was filled almost entirely with its guts? Brachiosaurus is said to have consumed up to 200 kilograms of plants in a day, so naturally its stomach had to be huge to accommodate all this food, and the intestines too had to be long to digest this tough food. Until as recently as 1998, experts only guessed as to what the dino's insides may have looked like, but when two dinosaurs from China were found with their guts intact that year, many interesting facts were revealed. In some instances, small stones too have been found in the rib cages of many dinosaurs. As few dinosaurs could move their jaws from side to side, and had no ability to chew their food, they probably swallowed it whole, along with small stones (gastroliths) to help them grind food as it churned about in their stomach. You may be aware that chickens swallow grit for this same purpose.
These bones had been too big to belong to unborn Coelophysis, so, experts believe these particular therapods may have eaten the young of their own kind when food was short. Other theropods may have also been cannibals. Meat-eating dinosaurs too came in all shapes and sizes. They ranged in size from chicken-size Saltopus (60 centimetres) to huge Tyrannosaurus (about 12 metres long). Big theropods such as the Tyrannosaurus, Allosaurus and Dilophosaurus may have hunted large plant eating dinos. The speedy Troodon may have survived on small reptiles and mammals. It may have also snatched unguarded eggs from other dinosaur nests. Struthiomimus, Avimimus and Oviraptor used their strong beaks to catch and crush insects and eggs.
Deinonychus (terrible claw) and its relatives are known to have specialised in using their claws to kill animals much larger than themselves. They had deadly claws about 12 centimetres long on the second toe of their back foot which they used to slash their victims. The Deinonychus, though small, is believed to have hunted in packs like the wolves of today. Hunting in a pack may have enabled them to even attack larger prey such as the young of Diplodocus, separating it from the rest of its herd. Their eyesight too would have been sharp as they had forward-facing eyes and good binocular (overlapping) vision like modern owls. *** Shapes of teeth The size and shape of dinosaur teeth depended on what it ate. The ornithopod Heterodontosaurus had sharp narrow front teeth for cutting and slicing. Plateosaurus (2), and sauropods like Diplodocus (3) and Apatosaurus (4) had peg-like teeth to shred and crush food. Stegosaurus (5) had leaf-shaped teeth for slicing and munching soft plants. The sharp, backward pointing teeth of Megalosaurs (6) is typical of many large meat-eating dinosaurs. They were used for gripping and ripping their prey. *** Dino facts * Apatosaurus was once called Brontosaurus, or 'thunder lizard'. * Diplocoducus or 'double beam', called so after the shape of a type of bone found in its tail, was the longest-ever land animal. It grew up to about 27 metres long. * Brachiosaurus, 'arm lizard' was so named because its front legs were longer than most sauropods. * Struthriomimus was a bird-like beast who may have stolen eggs * One of the first bird-hipped dinosaurs was Fabrosaurus which was no bigger than a lizard. It had a horny beak and was discovered in Southern Africa. * Parasaurolophus had a horn curving backwards from the top of its head *** Lizard and bird hips Experts divide dinosaurs into two groups according to the shape of their hips. Sauropods (plant-eaters) had lizard hips. As their big stomachs unbalanced them, they had to walk on all four legs. Two-legged theropods (meat-eaters) also had lizard hips Plant-eating, bird-hipped dinosaurs evolved later and many walked on two legs. Armoured bird-hipped sauropods were so heavy that they had to walk on all four legs. |
|
| News | Business | Features
| Editorial | Security
| Politics | Produced by Lake House |
All meat-eating or carnivorous dinosaurs were therapods which means
'beast foot'. They walked on two legs. They had three toes which were
armed with sharp claws. Therapods are believed to be fierce hunters and
scavengers. Some may have been even cannibals, as fossils have revealed.
The remains of Coelophysis found in New Mexico, United States, had
skeletons of young ones inside the stomach. 
Experts think that dinosaurs such as Baryonyx would have snapped up
fish with their long crocodile-like jaws and also speared the fish with
the huge hook-like claw on its front feet, like brown bears or grizzlies
do. 
