Tuesday, 26 July 2016

Six dinosaur myths explained

The first dinosaur bone found in 1676 was thought to come from an elephant or perhaps an unknown giant. After a century, scientists realised such fossils came from a creature they named "Megalosaurus", portrayed as a sort of stocky, overgrown lizard. Then, in 1842, leading anatomist Richard Owen recognised Megalosaurus as part of a whole new group of animals, which he named Dinosauria, or Terrible Lizards. Ever since, around 700 different dinosaur species have been discovered, with more found every month. Our ideas about dinosaurs have also changed radically. The dinosaurs we know today are very different from the ones in the books you may have read as a child. In this list we can see some common myths about dinosaurs.


1. Dinosaurs were all big. Dinosaurs came in all sizes.

The name dinosaur tends to evoke images of a gigantic creature – and certainly many were very large. Tyrannosaurus Rex (aka T.Rex) was around 12 metres long and weighed more than five tonnes, about the size of an average elephant, and it probably wasn’t even the biggest carnivore. Long-necked, plant-eating sauropods grew to titanic proportions. The enormous Argentinosaurus is known from just a few bones, but its size has been estimated at 30 metres in length and 80 tonnes in weight. That’s larger than any living land mammal and all but the largest whales. And dinosaurs are unique here. No other group of land animals before or since was able to grow as large.

Still, not all dinosaurs were giants. The horned dinosaur Protoceratops was the size of a sheep. Velociraptor was the size of a golden retriever and had to be enlarged in the film Jurassic Park to make it more terrifying. Recent years have seen an explosion in the number of small species discovered, such as the cat-sized raptor Hesperonychus, the rabbit-sized plant-eater Tianyulong, and the quail-sized insect-eater Parvicursor. The smaller species were probably more common than their giant cousins. It’s just that the massive bones of a T.Rex are more likely to have been preserved and a lot easier to spot in the field.

2. Dinosaurs were all scaly. Dinosaurs were scaly and feathery.

When dinosaurs were first discovered, it seemed quite obvious that since they were related to crocodiles and lizards, they must have been scaly. And many dinosaurs – including duckbills, horned dinosaurs, sauropods, and armoured dinosaurs – do preserve scale impressions.

But in the 1970s, palaeontologists began wondering if some dinosaurs might have been feathered, like their bird relatives.
This was considered wild speculation at the time, but in 1997 a small carnivorous dinosaur named Sinosauropteryx was found to be covered not with scales, but a soft, fuzzy down. Since then, feathers have been discovered on the plant-eating ornithopods, fanged heterodontosaurs, and many families of carnivorous dinosaurs including Tyrannosauridae - meaning that T. Rex was probably covered in feathers, not scales.

3. Dinosaurs were all green and brown. Dinosaurs came in all colours and patterns.

Pre-Historic paintings of dinosaurs showed monotone animals dressed in depressing shades of grey, green, and brown. But in reality, the colours would have been much more vibrant, even garish.
Studies of dinosaur scales and feathers have revealed traces of melanin, the same pigment that lends colour to lizard scales, bird
feathers and our hair. Analyses show that dinosaurs came in a wide variety of colours including black, white, and ginger. A few show-offs even had an iridescent sheen to their feathers.
Not only that, but many dinosaurs were boldly patterned with spots and stripes, white bellies and dark backs. Some of these patterns probably evolved as camouflage, to help dinosaurs hide from predators and prey. But bright colours and conspicuous patterns would have served to draw the eye of potential mates, much like the tail of a peacock.

4. Dinosaurs were bad parents. Dinosaurs protected their decendants.

Most reptiles simply bury their eggs and walk away, leaving their offspring to fend for themselves as best they can. This hands-off parenting is extremely risky. Dinosaurs were once thought to use the same strategy reptiles today use. But that surely was not it. Living dinosaur relatives – birds and crocodiles – guard their eggs and their young, so it’s a reasonable assumption that the dinosaurs
did as well. And there’s now evidence of this. When expeditions to the Gobi Desert found a dinosaur atop a clutch of eggs, it was assumed to have died while plundering the nest. It was named Oviraptor, or "egg thief". But then more skeletons were found atop clutches of eggs, sitting on them like brooding birds. It turns out Oviraptor didn’t eat eggs - it was guarding them.







5. Dinosaurs were doomed to extinction. Some dinosaurs adapted by time.

Dinosaur extinction was long blamed on some failure of the dinosaurs themselves, a failure to adapt to the changing environment. In reality, dinosaurs were diverse for more than 100 million years with fossils found in North and South America, Asia, Europe, Africa, and even Antarctica.

Although some argue this diversity was in decline, the fossils show that dinosaurs remained widespread, common and diverse until 66 million years ago, when an asteroid struck Earth in what is now Mexico. Debris from the impact blocked out the sun and plunged the world into darkness.
The disappearance of the dinosaurs wasn’t fated – it was a cosmic accident. If the asteroid had deviated by a fraction of a fraction of a degree, dinosaurs would still rule the planet – and we wouldn’t.

6. Dinosaurs all became extinct. A few remained after the disaster.

The asteroid mentioned earlier wiped out almost all the dinosaurs, but not all. The T. rex, Triceratops and the rest disappeared, but a handful of small feathered dinosaurs, probably less than a dozen species, survived. They were birds - small, flying cousins of T. rex and Velociraptor and the direct descendants of the carnivorous dinosaurs. And they not only survived but thrived, evolving into some ten thousand species of birds. One of these is now more commonly known as, the chicken.

We do not own this article. This article is owned by "The Conversation" and was modified and redistrbuted by us. For mor information visit https://theconversation.com/the-top-six-dinosaur-myths-and-how-we-busted-them-59031. Images are also not owned by us, they can be easily found by google search for reference.
KSGenre © 2016. Article edited by Kyle Farrugia. 

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