Dragon. Dragons are imaginary beasts with a long history in the folklore of many cultures. Usually the dragon is a crafty creature that represents evil. The word dragon, as used in some translations of the Bible, is often confusing. Occasionally this word is used when the intended meaning was probably jackal (Lam. 4:3), (RSV), sea serpent or serpent (Ps. 91:13), (RSV), or even crocodile (Ezek. 29:3-4).
Behemoth. A “behemoth” has the general idea of a very large animal. While this is its idea, the specific animal referred to in the Bible is in question, a bison, or some other animal.
The largeness or large size of the animal is what is the concept. These animals were like elephants only bigger. They move about and anything or anybody in their way is in danger of their weight and size.
Leviathan (see Crocodile).A Leviathan in the Bible is a monster from the sea.
A unicorn is a mythical creature, similar to a horse, with a single spiral horn growing out of its forehead. In the Middle Ages, the unicorn appeared in paintings as a symbol of purity. Many people believed an animal like this really lived. In the Bible, most verses that refer to the unicorn emphasize its great strength (Num. 23:22; 24:8; Deut. 33:17). The biblical writer may have had the aurochs in mind. This horned wild ox was so large and powerful that no one could control or tame it (Job 39:9-10; Ps. 22:21; 92:10; Is. 34:7).
Sea Monster. Several terms are used in the Bible to describe large sea creatures: sea monsters or serpents, dragons, great fish, whales, and Leviathan. All of these do not refer to one animal, but it is impossible to match the terms with specific marine life. For instance, many animals have been mistaken for sea serpents– large eels, sharks, and giant squid. The Mediterranean and Red Seas contain whales and enough other such “monsters” to provide plenty of material for sea-related scare tales.