To answer your first question: Most people would say that dinosaurs are not mentioned in the Bible. And they would be wrong. Oranges are also not mentioned in the Bible and yet no one would deny an orange for supper. Contrary to popular belief, dinosaurs are mentioned in the Torah, and no, it's not what you think. No, it's not Genesis 1:21's "taninim gedolim", translated as "great sea monsters" and it's not Leviathan, either, which means whale. Rather, the first time we read about dinosaurs is in the beginning, as you would expect.
And G-d said, "Let the waters swarm a swarming of living creatures,
and let fowl fly over the earth, across the expanse of the heavens."
On the fifth day, G-d created birds. True, birds do not look like dinosaurs, and dinosaurs do not look like birds, but archaeologists have proven that birds are not only modern descendants of dinosaurs, they are dinosaurs. Dinosaurs are mentioned elsewhere in the Bible. A lot of people would laugh at the notion that Noah saved the dinosaurs on the Ark. He did. Noah sent a raven and a dove to look for land.
As to your second question: Even if readers do not like this approach and admit that dinosaurs, as in giant reptiles or Tyrannosaurus are not mentioned in the Torah, we can answer that “the Torah speaks in human language” (Rabbi Ishmael). Because the Torah was given to the generation of emancipated slaves, it could not expect them to understand science and evolutionary biology. As a result, it had to work with the time it was given.
 Although some read taneneem to mean crocodiles, snakes, or dragons
 As are all reptiles