Dinosaurs still stalk the Earth and may even live in your house, in a cage, according to a research scientist from the University of California.
The family budgie might not look like one of the scary creatures depicted in Jurassic Park, but the two species even have feathers in common, the British Association at Sheffield was told. For birds live on the same branch of the tree of life as dinosaurs, and are direct descendants.
"Birds actually are dinosaurs, but strange ones, like we are primates but strange ones," said Prof Ken Padian. Although we are more aware of the differences than the similarities, we are of the same order as the apes. Birds and crocodiles are two evolutionary lines which can be traced directly back to the dinosaurs, he said.
Dinosaurs had breast bones and wishbones of a remarkably similar design to those of modern birds, he said, a similarity which had prompted a colleague to describe the ferocious carnivore, T-Rex, as the "five-tonne roadrunner from hell".
They were part bird and part lizard, he said. "They probably were all of these things."
New fossil discoveries have also demonstrated that a wide range of dinosaurs had feathers. "Feathers didn't evolve for flight," he said, because they pre-dated birds as we know them. They could have been used for camouflage, for mating display, species or gender recognition, or insulation.
Much could be learned about dinosaur movement, behaviour and even sexual practices through the detailed study of the fossil records, said Dr David Norman of the University of Cambridge.
Studies of joint wear enable us to understand how limbs might have moved against one another. Advanced computer graphics have been merged with highly-detailed CAT scans of dinosaur skulls.
Once programmed, the computer can run a moving picture of how the skull might have flexed, for example during feeding.
"The behaviour of modern animals helps us to interpret the likely behaviour of extinct ones," said Prof Neill Alexander of the University of Leeds. Most popular pictures of dinosaur interaction showed a carnivore trying to take a bite out of a plant-eating species, but the most likely purpose for dinosaur weapons and protections was to enable males to wage war against one another.
"Most fights are between individuals of the same species. More specifically, they are between males of the same species and they are fighting over females," he said.
Dinosaur mate selection probably followed similar patterns to those seen today. Evolution was geared, he said, towards "choosy females" who were in the market to select the best possible male.
In modern animals this was done by elaborate displays as in peacocks, a clash of weapons as with red deer, or head-butting as with rams and boars. "There are structures in dinosaurs that suggest a similar behaviour," he said.
Triceratops' three-horned head neatly meshed with an opponent's for a deer-like fight, he said. Some dinosaur species had elaborate frills and crests that were weak and could not have been for defence or assault, but would have been good for display.
Inflatable bag-like structures and hollow channels in the skull and associated frills could have been used to produce loud sound effects to help attract females. These mating strategies paralleled those seen in modern species, Prof Alexander said.
