The riddle of the Sphinx

An important element in Sophocles, Oedipus the King is the Sphinx and her riddle. To be sure, the content of the riddle is never specified in the play. There are, however, a number of specific references or allusions to the Sphinx in the play (H&P, p. 707, line 37; p. 710, line 131; p. 717, line 382; p. 720, line 485)
Quite a few versions of the riddle are available, but most of these probably represent some distortion of the form in which it was familiar to Sophocles' audience. The version which is most familiar today runs something like this, available on the web at History For Kids:

"What goes on four feet in the morning, two feet at noon, and three feet in the evening?" (H&P give essentially the same version, p. 693, but with "legs" in place of "feet".)

Ancient Greek sources, such as Apollodorus and Athenaeus, on the other hand, give a different emphasis to the riddle.

Apollodorus' version is the more widely available. It runs as follows:

"What is that which has one voice and yet becomes four-footed and two-footed and three-footed?"

Also important is Athenaeus' somewhat fuller version, available at a Sophocles website, as follows:

"A thing there is whose voice is one;
Whose feet are four and two and three.
So mutable a thing is none
That moves in earth or sky or sea.
When on most feet this thing doth go,
Its strength is weakest and its pace most slow."

Besides this relatively comprehensive version, there is also evidence for a shorter version, consisting of just one dactylic hexameter line, as follows:

"A thing there is whose voice is one;
Whose feet are four and two."

One possible answer to this form of the riddle is "a pastoral society" (i.e., one in which humans and their animals live in close association with one another). Such a formulation of the riddle is important at various points in Oedipus Rex. For example, the plague is described near the beginning of the play (H&P, p. 707, lines 24-25) as affecting both the flocks and women of Thebes. Also, it is eventually the two shepherds (from Corinth and Thebes respectively), who have lived in close association with their flocks (H&P, p. 742, lines 1082-1090) who eventually provide the key evidence for explicating Oedipus' background.

More generally, evidence for the importance of a variety of different forms of the riddle emerges in the confrontation between Oedipus and Teiresias (H&P, pp. 714-719, lines 289-453). This can be viewed in terms of Teiresias' having realized that the riddle did not admit of any simple solution, whereas Oedipus, brilliantly, but with ultimately fatal consequences, picked out just the answer "man".
Particularly striking evidence of the importance of a multitude of riddles in the play comes in the concluding lines, in which, finally, there is a reference to riddles - in the plural - rather than a single riddle. This point is, however, obscured in many translations (including Cook's translation, in H&P), in which the Greek plural ainigmata (which Sophocles uses in place of the singular ainigma) is translated just as "riddle". For the original form of the text, though, see an on-line essay which includes the following translation by David Grene. (The passage from Grene's translation is found near the end of the essay.) [Emphasis on word "riddles" added]:

You that live in my ancestral Thebes, behold this Oedipus,- him who knew the famous riddles and was a man most masterful; not a citizen who did not look with envy on his lot-see him now and see the breakers of misfortune swallow him! Look upon that last day always. Count no mortal happy till he has passed the final limit of his life secure from pain.