In the account about the converting of Moses’ rod into a snake (Ex 7:9-13), the Hebrew word tan·ninʹ is used, evidently referring to a “big snake” in view of the use of the word in other texts as describing a monstrous creature of the sea. (Ge 1:21; Job 7:12; Ps 74:13; 148:7; Isa 27:1; 51:9) Other texts where the term clearly applies to venomous snakes are Deuteronomy 32:33 and Psalm 91:13, where cobras are also mentioned. A fountain in postexilic Jerusalem was known as “the Fountain of the Big Snake.”​—Ne 2:13.

At Jeremiah 51:34 the inhabitress of Zion likens King Nebuchadnezzar to a “big snake” that has swallowed her down.