What is the symbolism for a crocodile in the Bible?

I got the answer out of my science text book - Life Science . It's in Christian perspective. It says "... In Job 41 God describes a creature called the leviathan, a mighty, untameable, fearless animal with tightly fitting scales and a mouth full of terrible teeth. The leviathan lived in the water, which it was able to churn with its great strength. Some people think that this description fits the crocidile. However, one of the characteristics of the leviathan is that " out of his mouth go burning lamps, and sparks of fire leap out. Out of his nostrils goeth smoke."(Job 41:19- 21). Taken literally, these characteristics are not like those belonging to the modern crocidile. Was the leviathen a fire breathing dragon ?Maybe God was using poetic language but it might be possible that a firebreathing dragon exsisted. Scientists have found large chambers in certain dinosaur skulls. These chambers do not exist in skulls of living organisms, and scientists are not sure of their function. An extinct reptile sometimes called the "SuperCroc" measured up to 12 m (40 ft) long and may have weighed 10ton.At the tip of its nose it has chambers that could have special chemical producing glands that made fire. This chemical reaction might be similar to the bombardier beetle's reaction. ( look it up) The point of this animal in scripture ( crocidile or dragon) is to point out God's power. It doesn't have a symbolic meaning. It is put their to show that God is so mighty he made the leviathen.