In the first place, there is no logical reason for scientists to date dinosaurs before man. They do so simply because of their evolutionary model and a presupposition that dinosaurs and man could not have cohabited. In fact, tracks of dinosaur and human footprints have been found in the Puluxy River bed in south Texas fossilized in stone. These tracks actually cross providing strong evidence for the co-existence of dinosaur and human.
Further, the Bible certainly includes dinosaurs when it speaks of the creation of all animals in Genesis 1:25 and again when the animals were taken into the ark (Genesis 7:2).
Job gave descriptions of two animals that are unlike anything we have ever seen today. The descriptions of Behemoth (Job 40:15-24) and Leviathan (Job 41) are as dinosaur-like as one could get.
Remember, that about 18,000 species of animals have become extinct since the flood (that is, there are over 18,000 species of animals in the fossil record that are not alive today). It is therefore not surprising that a few dinosaurs became extinct along with so many others.
By the way, travel to the zoo and go to the reptile section and see if you don’t see some animals that would be considered dinosaurs if they were found as fossils instead of alive!