While we understand from Genesis one that animals and mankind were created on the sixth day, there remains a question among theologians and scientists about the origin of dinosaurs. Some believe they were part of the sixth day of creation activities. Others take the position that they resulted from hybridization of some reptiles God originally created.
Some people think the references to "leviathan" (Job 41:1), "behemoth" (Job 40:15) and dragons (many texts) are references to dinosaurs. Most Bible scholars suggest that the descriptions in Job are of crocodiles or hippos. Both lived in the Near East in those days. It is tempting to think that dragons are a faded memory of dinosaurs but we cannot be sure. We can only speculate.
Those who have collected dinosaur remains in the Midwest plains of Canada and the United States or in the Colorado Plateau region have no lingering doubt concerning their reality. Thousands of specimens have been found and excavated.
The fossil remains of these reptiles indicate that they were indeed a highly diversified group, ranging in size from that of a rabbit to tremendous beasts 20 feet high, 85 feet long, and weighing up to 50 tons. It appears that some were relatively light-footed and had bipedal locomotion, while others were quadrupedal and moved about in a slow and cumbersome manner. Some were carnivores and others herbivores. Certain types were well suited for aquatic habitat while others remained on land.
The sudden extinction of the dinosaurs, as shown by the geological records, is a mystery that evolutionary paleontologists have considerable difficulty explaining. What happened? Change of temperature? Change in the plants? Blasts of heat from a meteor; mammals eating dinosaurs eggs; hyperpituitarism; change in oxygen concentration; over-specialization and senility of the dinosaur stalk; etc. These are some of the rationalizations of scientists. The current dominant theory is that a large object from space hit the Earth and blasted up so much dust that the sun was obscured for months and the plants and animals died. However there are problems with this theory also because the extinction was selective. Some plants and animals (including fragile ones compared to dinosaurs) did not become extinct.
When God directed the animals into the ark, He no doubt directed only those that were like His original created types. There is little evidence that dinosaurs were taken into the ark. That God did not preserve them in the ark and that they died as a result of a world-wide flood is as good an explanation as any.
Why did God not take dinosaurs into the ark? In Genesis 6:12 we find the statement, "And God looked upon the earth, and, behold, it was corrupt; for all flesh had corrupted his way upon the earth." Satan, the being who rebelled against God, cannot create, but he can change (even as modern scientists can produce change through mutations, hybridization and genetic engineering). The entrance of sin into the world allowed Satan to corrupt humans and other living organisms. Now we have leaves changed to thorns, teeth changed to poison fangs, genes changed into viruses and useful bacteria into disease producers. Satan corrupted some of the reptiles God originally created into the bizarre creatures we call dinosaurs. God chose not to save them at the time of the Flood. Perhaps God also saw that feeble post-flood humans would not be able to control such large animals. Thus we suggest that God preserved the air-breathing, land animals except the very large animals and the corrupted ones.