Riddle of the Sphinx

Everything About Fiction You Never Wanted to Know.

"What walks on four legs in the morning, two legs in the afternoon, three legs in the evening, and no legs at night?"


The classic riddle presented to Oedipus Rex by the Sphinx in Greek Mythology. He was the first one to solve it—all the others who failed were eaten by the Sphinx—after which she threw herself down a chasm. This is one of the oldest Stock Puzzles out there, going back to the Greek writer Apollodorus in the second century CE.

The answer? As a baby, a human goes about on all fours ("four legs in the morning"; morning = childhood), until he learns to walk, which he does so well into adulthood ("two legs in the afternoon"; afternoon = adulthood), until old age requires him to use a cane to support himself ("three legs in the evening", evening = old age), finally he dies ("no legs at night", night = death). So the answer is "a man".

This trope is about the riddle; it may or may not be delivered by a sphinx. The more general trope for sphinxes that ask riddles is Riddling Sphinx.

Also see Riddle Me This, These Questions Three.

Examples of Riddle of the Sphinx include:

Anime and Manga

  • Parodied in Final Fantasy Unlimited episode 16, where the "correct" answer is the Hemoran bacterium. The person who answered "a human" got it wrong.
    • Parodied again in the same sequence when someone tries a ridiculously complicated answer to a riddle...and the "correct" answer is the simple, obvious one. As it turns out, the entire quiz is a sham.
  • Used by a riddle-based time-shifter in Flint the Time Detective. The Quirky Miniboss Squad, stumped, tries to guess a chimpanzee.
  • Sakon from Karakurizoushi Ayatsuri Sakon corrects a man who tells him about the Egyptian riddle of the sphinx.


  • Played with in Mirror Mask. Helena, when asked this riddle, answers with the name of the performing dog from the circus in which she grew up. The sphinx tells her that the answer is man, and she responds...

Helena: Nuh-uh. I saw him. He was walking on four legs in the morning, two legs during the afternoon show, and he was limping on three in the evening because he hurt his paw! He can skateboard, too.



  • Subverted in Percy Jackson and The Olympians during The Battle of the Labyrinth, Percy and the gang meet the Sphinx who, like everything else in Greek mythology in this series, gets modernized. She now uses an SAT style automatic grader and asks random trivia questions. Annabeth, who was taking the quiz expecting to hear the original questions, takes this as an insult to her intelligence and refuses to take the quiz. Guess who has to fight a Sphinx.
  • Spoofed in the Discworld novel Pyramids. Pteppic encounters a Sphinx who asks him this riddle. He's unable to answer, but protests that the metaphor is overly simplistic, forcing it to give a more accurate version covering all possibilities. Pteppic answers this and walks off before the Sphinx remembers that it had already told him the answer.
  • Parodied by John Sladek, in a story parodying Cordwainer Smith. "The answer is a coffee table. I fixed four legs to it in the morning but two legs fell off in the afternoon, and by the evening I'd only gotten around to replacing one of them."
  • In Gene Wolfe's Soldier of the Mist, Latro meets up with the same sphinx. He answers that it is a man going a journey: in the morning, he rides a horse, but when the horse is stolen, he walks, and then in the evening, he cuts himself a walking stick. This answer was also approved by the sphinx.
  • In John Barnes's One for the Morning Glory, the Riddling Beast at the edge of the goblin kingdom asks, "What goes on four legs in the morning, shaves the barber at noon, and crosses the road in the evening, and what does it have in its pockets?" Prince Amatus correctly answers "Myself and the things that are mine" because the answer to such riddles is always "myself"—though the pockets nearly threw him. Later, they turn about the Riddling Beast so it guards the way out of the goblin kingdom—which is good, because a goblin can not easily answer a riddle whose answer is "myself and the things that are mine."
  • In the book Pyramid Scheme the Sphinx can only eat someone who fails to answer her riddle. The heroes, of course, know the answer (although there's a certain amount of tension because while the guy being asked knows the answer, he doesn't know Ancient Greek....) After hearing the Sphinx complain about how hungry she is they offer to teach her a new riddle in exchange for her help. After they escape the myth world, the Sphinx gets a job as a greeter / tourist attraction at the Luxor hotel in Las Vegas. She asks guests riddles in exchange for all the food she can eat.
  • In The Stress of Her Regard, it's revealed that Oedipus only answered correctly by accident: its intended answer is "sentient life on Earth", and the "legs" are the atomic bonds in the skeletal structures of Earth's primordial silicon-boned, present calcium-boned, and future aluminum-boned inhabitants. (The former are the novel's vampires, and the latter are presumably robots.) It's implied that Oedipus actually said "people", and the sphinx didn't grade his answer too harshly.
  • In the Amber book Trumps of Doom Merlin briefly encounters a sphinx that asks him a riddle. He gives an answer which, while not the one the sphinx wanted, did meet the conditions of the riddle. Eventually after giving the sphinx a ridiculous one[1] he just threatens the sphinx until it agrees to let him go.
  • The riddle is the reason that the members of the Club in Esther Friesner's "The Wedding of Wylda Serene" accepted the sphinx that one of their members brought, figuring that everyone knew the answer, so no one would get eaten. Then she learned some new ones...
    • In her novel Sphynxes Wild, the sphinx—currently operating as a Greek heiress in Atlantic City—is the villain, and not until the hero finally answers her new riddle can she be defeated.
  • Gollum tells a version of this riddle in The Hobbit. Bilbo answers correctly.

Live-Action TV

  • Kyoryu Sentai Zyuranger has this as one of the questions asked by Dora Sphinx- his victim, who'd answered every riddle correctly until then, didn't get this one.


  • Mentioned in PDQ Bach's Oedipus Tex (of course), where a "Bigfoot" plays the Sphinx's role and Oedipus plays that of his brother Rex.

Newspaper & Magazine Comics

  • Spoofed, along with many other stock riddles, in Sovisa when Alexi is confronted by a riddle-telling old man (a further spoof, in that the man states it's one of the few jobs a man of his age can hold down), Alexi antagonizes him by answering his riddles before he's finished telling them. A section of the text is as follows:

Man: Listen well to your first fiendish riddle, foolish boy! "What walks on four legs in-"
Alexi: Man.
Man: What? What do you mean "man"?
Alexi: It's the answer, I've heard that riddle around a hojillion times.
Man: Well then get ready for round two! "As I was going to St. Ives, I-"
Alexi: One. One was going to St. Ives.
Man: OK, wise-ass, no more Mr. Nice Granddad. "I'm the beginning of Eterni-"
Alexi: The letter "E". You know, you could try to put some effort into this.
Man: Do I come to you at work and tell you how to do your job? No. -Startin' to piss me off, boy. Right, "I occur once in a minute, tw-"
Alexi: The letter "M", I see we're stuck on letters now.
Man: All right. I see I'll have to pull out all the stops. "You come to two doors, guarded by a pair of men, one tells only the truth, wh-"
Alexi: The truth or lies guys riddle? Seriously? You know, I don't think you eve- Ow! You kicked me!


Stand Up Comedy

  • The comedian Richard Herring says the answer shouldn't be a man because a stick isn't really a leg. The real answer should be Paul McCartney and his wives.
  • An Emo Philips routine postulates that the answer is a donkey, "who has four legs in the morning, then in the afternoon you chop two of them off, then in the evening you glue one back on again."

Tabletop Games

Video Games

  • Used in Devil May Cry 3, where you were supposed to walk through the doorway with the right number of glowing eyes. Picking the wrong doorway led to a fight against several monsters and a Puzzle Reset.
  • The third-level boss of Wario Master of Disguise for the Nintendo DS has the player answering a sphinx's riddles, the answers being objects you saw during the level (including the "man" riddle). Miss a question and you die instantly.
  • At the end of the Tombs of Amenti in Valkyrie Profile, you are asked this riddle. The choices are "Humans", "Man", and "Homo Sapiens", so it's impossible to get it wrong.
  • Referenced in gruesome fashion by the Riddler in Batman: Arkham Asylum: he claims the answer is "a baby", because it walks around on four limbs, but it walks on only two if you cut off its legs and three if you give it a crutch. When asked how he could make such a sick joke, the Riddler calmly responds "It's not my baby."
    • The Riddler also poses this riddle to Booster Gold in the cold open of an episode of Batman the Brave And The Bold and gives Batman an electric shock when Booster can't answer it.
    • In an issue of The Batman Adventures the Riddler robs two men (i.e., four legs) in the morning, one man in the afternoon, and a man with a cane in the evening. Batman realizes that this means the Riddler is hiding out in a building with a giant sphynx statue on the roof. When Batman explains how he tracked him down, a shocked Riddler reveals that he had been making a conscious effort to commit a crime without leaving clues, and that the pattern of his crimes was entirely subconscious. The shaken villain surrenders and asks to be taken to Arkham, realizing for the first time that he might really need help.
  • Averted in the Riddle of the Sphinx video game, which has nothing to do with this old trope except the name.
  • Shows up in the Unexpected Text Adventure section of NieR.
  • Played with in Monster Girl Quest. As part of a trial to be eligible to marry a dragon, a Sphinx gives this question, and it is lampshaded by Luka how almost everyone knows the answer to this question and that it's anticlimactic. The riddle's true purpose is to illustrate that any monster and human romance will be a Mayfly-December Romance and to make the trial taker aware of this fact and its implications. Note that if Luka answers, "Me!" the Sphinx accepts that as correct, as Luka is human.

Web Comics

  • Nerf Now: If this question ever comes up in Jeopardy!, Dracula's got it covered.
  • Parodied on these two pages of Gastrophobia, where everyone knows the Sphinx's riddle. But they don't have to be so rude about it. It's to the point where she's now trying to think up a new riddle.
    • She's briefly excited when someone incorrectly answers "Goblin"...but then she realizes the speaker is a goblin, and is forced to admit that it counts.
  • Same riddle, same characters, different outcome.
  • Phix from 'Wapsi Square' is the Sphinx. Subverted in that Phix was one of a number of sphinxes, and the one who thought killing someone based on a riddle was a really stupid idea. She's glad, however, to have left those days behind.
  • Subverted in this Saturday Morning Breakfast Cereal comic.

Western Animation

  • Used particularly badly in one episode of Extreme Ghostbusters, where a ghost modeled on the Sphinx asks this of its victims and renders those who answer incorrectly into helpless, mindless beings. This includes an entire chapter of Mensa, the one group of people who you would expect to know the answer.
  • Similarly, the opening of an episode of The Mummy: The Animated Series had the O'Connells, a family of Adventurer Archaeologists/Egyptologists, oblivious of the answer to the riddle. You'd think at least Evie would know...
  • Also parodied in Sabrina the Animated Series: The sphinx gives the riddle, and Sabrina answers, "Man." However, the answer is the nine-legged... some creature that exists only in that world.
  • Used in the My Little Pony cartoon, in the episode "The Golden Horseshoes."
  • Ulysses 31: The Secret Of The Sphynx had this, strangely most mythology used in the show was based on Greek mythology, and the Riddle is also Greek, but it was all done in an Egyptian setting.
  1. about a frog in a cuisinart