"The Bible does not mentions dinosaurs. Since it doesn't with dinosaurs being so abundant in times past it can't be reliable as the Word of God."
First you have the , "Behemoth" which cannot be a Hippo because of Job 40:17 "He bends his tail like a cedar". A hippo has a short tail like a pig. Behemoth, had a large tail shaped like a cedar tree (large and tapered). I believe a better choice is that Behemoth is a Brachiosaurus type of large land dwelling dinosaur. It fits the description perfect.
The word dinosaur is a fairly new word (1800's) it would not have been used when the Bible was written because it was yet to be invented. Instead what if they went by another name? As for example dragon?
It is very interesting to note, however, that nearly every major ancient culture has myths and legends about giant reptiles. How would these civilizations, continents and millennia apart, all come up with legends of giant reptile creatures? Evolutionary scientists tell us that dinosaurs existed millions of years before human beings. Dinosaur fossils were not discovered until thousands of years after the myths of giants reptiles began. How can this be?
Dragon art from Babylon.
It is also interesting to note that some of the Books that have not been canonized mentions dragons. The apocrypha mentions dragon keepers at the court in Babylon, and that Daniel killed a dragon which was worshiped as a god. He baked pitch, fat, and hair (trichas) together to make cakes (mazas, barley-cakes, but translated "lumps") which he fed the animal. Though I would not recommend the Apocrypha to be read as part of the Bible it still paints an interesting picture.