From Bible Encyclopedia
This word is used for several Hebrew originals. In each case a poisonous serpent is clearly indicated by the context. It is impossible to tell in any case just what species is meant, but it must be remembered that the English word adder is used very ambiguously. It is from the Anglo-Saxon noedre, a snake or serpent, and is the common English name for Vipera berus, L, the common viper, which is found throughout Europe and northern Asia, though not in Bible lands; but the word “adder” is also used for various snakes, both poisonous and non-poisonous, found in different parts of the world. In America, for instance, both the poisonous moccasin (Ancistrodon) and the harmless hog-nosed snakes (Heterodon) are called adders. See Serpent.
(1) Akshub (“coiling” or “lying in wait”), properly an asp or viper, found only in this passage.
(3) Taiphoni (“hissing”) (Proverbs 23:32); elsewhere rendered “cockatrice,” Isaiah 11:8; Isaiah 14:29; Isaiah 59:5; Jeremiah 8:17, as it is here in the margin of the King James Version. The Revised Version has “basilisk.” This may have been the yellow viper, the Daboia xanthina, the largest and most dangerous of the vipers of Israel.
(4) Shephiphon (“creeping”), occurring only in Genesis 49:17, the small speckled venomous snake, the “horned snake,” or cerastes. Dan is compared to this serpent, which springs from its hiding-place on the passer-by.