Hastings' Dictionary of the Bible (1898)
LEVI'ATHAN, the Hebrew name of an animal minutely described in Job 41, the monster of the water, as behemoth was of the land. Probably- the crocodile is here intended — a reptile which resembles the alligator, but is larger and more formidable, with narrower snout, and feet webbed to the end of the toes. "The whole head, back, and tail are covered with quadrangular horny plates or scales, which not only protect the body — a rifle-ball
glancing off from them as from a rock — but also serve as ballast, enabling the creature to sink rapidly, on being disturbed, by Leviathan. (Crocodilus Vulgaris. After Tristram.) merely expelling the air from its lungs." — Tristram. It is believed that the crocodile was once abundant in the lower Nile to its mouth, but it is now rarely seen within the confines of Egypt. This reptile once abounded also in the Zerka or Crocodile River, which
flows through the Plain of Sharon, and doubtless in the Tigris. The crocodile seems to be meant by the word "leviathan" in Ps 74:14; Isa 27:1. But in Ps 104:26 the word is evidently used for some sea-monster, perhaps the whale. Several large cetaceous animals are found in the Mediterranean.