The Last of the Dinosaurs

The horned reptiles such as Triceratops were the last dinosaurs to appear. Then, about sixty-five million years ago, the dinosaurs died out. Not one was left.

Why they disappeared so suddenly and completely has long baffled scientists. There may have been many theories attempting to explain it. Some of them are described below.

Triceratops, one of the last dinosaurs to appear.

The Last of the Dinosaurs

Poor 'design'

It is easy to say that the dinosaurs vanished because they were replaced by more efficient animals. But since the dinosaurs lasted some 140 million years, compared with perhaps four million years so far for the human species, there cannot have been anything disastrously wrong with their 'design'.

Small brains

There is a widely held belief that dinosaurs had brains so pitifully small that they were barely able to move their huge bodies in attack, defence or the search for food. Particularly of the large, familiar dinosaurs such as Diplodocus and Stegosaurus it is often said that the animal's huge length would so delay the passage of nervous messages to and from its distant brain that it could not avoid danger to its rear end quickly enough. Some have even said the swelling of the spinal cord in the animal's hip region was a 'second brain' to speed things up. There is no truth whatever in this. The swelling was merely a huge bundle of nerves used to control the massive legs and tail of the animals.

Corythosaurus (above) and psittacosaurus were two more
dinosaurs that walked on two legs.

Just too big

Popular belief maintains that the lumbering monster dinosaurs could not fit in with the modern world. Here it is important to remember that many dinosaurs were small and fleet of foot. In any case, there are definite advantages in being large, since the body loses heat less quickly. Some say the dinosaurs could not compete with the mammals, or even that the mammals ate their eggs, but at the time the dinosaurs became extinct the mammals were too small and too few in numbers to offer any serious competition. Only when the dinosaurs had gone did the mammals spread across the world.

If the mammals did not drive the dinosaurs out, then the mammals must have been able to withstand whatever it was that made the dinosaurs extinct.