Job 41:1,15 “Can you draw out Leviathan with a hook, Or snare his tongue with a line which you lower?…His back is made of rows of shields (scales?), shut up closely as with a seal.”
A “leviathan” denotes a very large, fierce sea animal which moves by wiggling its body. The word is usually interpreted as referring to a scaled crocodile, but the creature could also be some unknown deep-sea monster! Figuratively, leviathan describes a cruel enemy, even that serpent Satan (Isaiah 27:1 with Revelation 20:2).
Is Job 41 speaking of dinosaurs? Possibly, but to state that Job 41 is speaking only of dinosaurs may be stretching the interpretation.
Another reference which might include dinosaurs is in the 5th creative day.
Genesis 1:21-24 (ESV), “So God created the great sea creatures and every living creature that moves, with which the waters swarm, according to their kinds, and every winged bird according to its kind. And God saw that it was good. And God blessed them, saying, ‘Be fruitful and multiply and fill the waters in the seas, and let birds multiply on the earth.’ And there was evening and there was morning, the fifth day.”
The “great sea-creatures” can be another reference to dinosaurs, but not exclusively. There are many animals which fit this description. Paleontology teaches us that dinosaurs did exist. They dominated the earth and suffered extinction during day 5. Furthermore, we need to properly understand that the term “day” means a period of time, and is not limited to a literal 24 hours.
Genesis 1:24 (NIV) records, “And God said, ‘Let the land produce living creatures according to their kinds: the livestock, the creatures that move along the ground, and the wild animals, each according to its kind.’ And it was so.” Thus, within the 6th day, the current classes of animals began to dominate the earth.
As exciting as studying dinosaurs may be, it is not of great importance in the Bible. The Bible essentially explains man’s fall from perfection, his redemption, and his restoration back to perfection. Dinosaurs were a fascinating part of creation but have no real part in the redemptive story of mankind.
Additional Resource: Christian Questions CQ Kids Video: "Did the Dinosaurs Live When Adam and Eve Were Alive?"