In the beginning... Edit
In Genesis chapter one it says God created the heavens and the Earth. Later on in that chapter it says that God also created every living thing including Dinosaurs. Modern science or should I say modern crap thinking scientists think that the universe and the Earth are both billions of years old. They only say that because they hate creation.
The Pre-Flood world Edit
After Adam and Eve sinned in the Garden of Eden the world was a dangerous place to live. Not only lions, tigers,and bears were a threat to early man. The most dangerous beings were the dinosaurs. Just think about it for a minute, people who only have spears going up against a 40 foot Tyrannosaurus-rex. Sounds crazy doesn't it? Well it is. According to theological estimates the Earth is about 6000 years old. So that means the dinosaurs could cause lot's of trouble for 2000 years. After that 2000 year period the Flood was coming.
For more information on the flood see Dinosaurs and the Flood.