The Hebrew word tan (plural, tannin) is so rendered in Job 7:12 (A.V.; but R.V., "sea-monster"). It is rendered by "dragons" in Deut. 32:33; Ps. 91:13; Jer. 51:34; Ps. 74:13 (marg., "whales;" and marg. of R.V., "sea-monsters"); Isa. 27:1; and "serpent" in Ex. 7:9 (R.V. marg., "any large reptile," and so in ver. 10, 12). The words of Job (7:12), uttered in bitter irony, where he asks, "Am I a sea or a whale?" simply mean, "Have I a wild, untamable nature, like the waves of the sea, which must be confined and held within bounds, that they cannot pass?" "The serpent of the sea, which was but the wild, stormy sea itself, wound itself around the land, and threatened to swallow it up...Job inquires if he must be watched and plagued like this monster, lest he throw the world into disorder" (Davidson's Job).
The whale tribe are included under the general Hebrew name tannin (Gen. 1:21; Lam. 4:3). "Even the sea-monsters [tanninim] draw out the breast." The whale brings forth its young alive, and suckles them.
It is to be noticed of the story of Jonah's being "three days and three nights in the whale's belly," as recorded in Matt. 12:40, that here the Gr. ketos means properly any kind of sea-monster of the shark or the whale tribe, and that in the book of Jonah (1:17) it is only said that "a great fish" was prepared to swallow Jonah. This fish may have been, therefore, some great shark. The white shark is known to frequent the Mediterranean Sea, and is sometimes found 30 feet in length.