The New Dinosaurs

Dinosaurs have always held a strong attraction for the world's youth. Most children have at one time or another been mesmerized while combing over picture books detailing these amazing creatures. Huge, slowly plodding animals, they ruled the Earth for 130 million years. Woops--did I say slowly plodding? New theories have completely changed the way scientists look at dinosaurs.

As dinosaurs evolved, they quickly spread around the world. Few species were able to withstand the rapid diffusion of the dinosaurs. There were many other contenders for dominance, but dinosaurs managed to succeed where all others failed. Even the mammals, which arrived on the scene almost as early as the dinosaurs, had to wait until the dinosaurs disappeared before making their bid for dominance.

Often mistakenly compared to crocodiles, dinosaurs were similar to present day reptiles with some important differences. The main difference was the possession of birdlike characteristics as well. They hind legs were very similar to those found presently in the worlds large flightless birds.

Originally, the large meat eaters were seen as slowly moving predators standing almost vertically with a long dragging tail. The more modern view sees these same predators moving quite rapidly with bodies oriented almost horizontal to the ground and the tail standing straight out behind. Their tender prey were similarly agile.

Dinosaurs were also originally thought to be cold blooded; today scientists are not so sure. Recent research has provided much more evidence to support the theory that they were indeed warm blooded and thus their activities were not regulated by the weather as in today's reptiles. One indicator of warm bloodedness is rate of growth. Most warm blooded animals grow very fast from tiny juvenile to full grown adult. Cold blooded animals, on the other hand, grown much slower. A python may take twenty years to grow to its maximum size whereas a stegosaurus could go from tiny juvenile to five ton adult in only six years.

Dinosaur bones, when studied closely under a microscope, more closely resemble todays warm blooded mammals than those of cold blooded reptiles. In addition, warm blooded animals require larger brains, hearts and lungs. Although most dinosaurs had quite small brains, many had large enlargements of the spinal chord which would compensate for the small brain size--almost like a second brain. Also, there is evidence that the hearts and lungs of dinosaurs were much larger than modern reptiles and similar to todays warm blooded fraternity.

As we learn more about the dinosaurs, the more inaccurate early literature appears to be. There is recent evidence that dinosaurs cared for their young. Most reptiles lay their eggs and that's the end of it. Discoveries of egg sites with individuals of varying age have helped show that they actually provided maternal care to their young. This may not seem like much but it shows how little we know about life prior to man coming onto the scene. Each day, paleontologists seem to come up with new information and it often contradicts earlier dinosaurian theories.