1. It is conceivable that Yahweh could have gone on questioning the serpent. But since the serpent had refused to acknowledge His covenant sovereignty there was no reason for Yahweh to extend It His arm of grace.
2. Åbe W. Sjöberg has suggested that the serpent may be a chameleon, a reptile with four legs but with its belly very close to the ground; the evidence he offers to back up his suggestion, however, is so meagre the article is a waste of time ("Eve and the Chameleon," in In the Shelter of Elyon: Essays on Ancient Palestinian Life and Literature in Honor of G. W. Ahlström, ed. by W. Boyd Barrick & John R. Spencer (JSOTSS 31; Sheffield: JSOT Press, 1984), 217-225.
3. G. J. Wenham, Genesis 1-15, (WBC 1; Waco, TX: Word Books, 1987), 80.