Running on All Fours

You know how they say "learn to crawl before you run"? Well, this character has learned to do both at once. This character may walk or run on two legs but is absurdly fast and nimble when running on all fours. Though running on all fours for humans is still possible, we've evolved to move faster and more efficiently through bipedal motion (our arms would have to be longer to be really good at it).

This character though is a bit of a throwback for doing otherwise, and a pretty successful throwback as well because they can run just as fast (if not faster) than on two legs. This atavism is represented by the character being Raised by Wolves, a partly non-human Beast Man or a Wolf Man. On the other extreme a Cyborg or genetically altered character might have this added as an alternate mode of locomotion. Then again, the Stringy-Haired Ghost Girl and other supernatural critters may move this way just for freaky kicks.

Sometimes, Funny Animals and Civilized Animals will assume this stance, whether as part of a Masquerade or not.

This Sister Trope of Primal Stance often involves Ceiling Cling, In a Single Bound, Wall Crawl and Wall Jump. The character can grab onto the roof, jump super high, run on walls and jump from object to object. Civilized Animals and Funny Animals are known to switch to all fours.

The polar opposite of Four Legs Good, Two Legs Better, where a quadruped adopts a decidedly humanoid gait. May constitute a mild example of Bizarre Alien Locomotion. Can be part of an Anthropomorphic Zig-Zag or Furry Reminder.

Examples of Running on All Fours include:

Anime and Manga

The eponymous hero of Naruto does this from time to time, especially in the earlier part of the series, when he was less aware of the 9-Tailed Fox sealed inside him. None of the other characters with Tailed Beasts sealed inside them exhibit this behavior.
- Kiba does this as well.
Berserk units in Neon Genesis Evangelion and Rebuild of Evangelion run this way.
Yamcha does this in Dragon Ball Z after he fails to catch King Kai's Monkey while running on two legs, as part of King Kai's training. He promptly catches him this way.
Merle in Vision of Escaflowne does this.
An early minor villain in 666 Satan does this due to an absurdly acute fear of heights.
Pokémon: Pikachu can function equally well on either four or two legs - they walk on two legs but run on four.

Comic Books

As the page pic shows, X-Men foe Sabretooth is fond of this across continuities.

Film

Several characters in Kung Fu Panda, Tigress being the most notable example.
In Legion, one of the angel-possessed humans (the ice-cream man) has his limbs elongate and allow him to really run on all fours like a demented spider.
Lampshaded in Madagascar when Marty invites Alex to try it.
The creatures in Pandorum alternate between bipedal and quadripedal running when chasing the heroes.
The Promise has all of the slaves used as bait in the opening battle move around like this because as slaves they weren't allowed to act like humans. The protagonist Kunlun is easily able to outrun all of his other fellow slaves, but it turns into an aversion since he does run faster bipedally—he's just that good of a runner.
Samara from The Ring, who crawls up the well and out of a TV set.
Played for Black Humor in Shallow Hal. The main characters have a friend with spina bifida, leaving him with limited use of his legs; thus, he gets around on all fours.
The Wolf Man, when transformed, tends to abandon bipedal running when not in the middle of killing someone, which is rare if there's anybody near enough to sink his claws into.
The Lycans of Underworld, when transformed, run on all fours on ground and through trees and can easily catch up with horses, either way.
In the movie The Animal, Marvin Mange, who has been implanted with various animal organs, starts running on all fours when being chased down by a truck.
Some Decepticons from the Transformers: Dark of the Moon.
Apes in the Planet of the Apes remake, although mostly bipedal, did this when they were really excited and in a hurry.

Literature

Goblins of Artemis Fowl are described as bipedal simpletons that revert to all-fours for running, specifically for the speed boost
Monk Mayfair from the Doc Savage novels sometimes does this (his arms are so long they almost touch the ground when he is standing up).
Gor: the alien Kurii are bipedal, but switch to all fours when running.
Some strains of ratfolk from the Garrett P.I. series run by bending forward and bounding on all fours, bouncing their palms off the ground as they go.
Some goblins are said to do this in The Hobbit. Justified because goblins have longer arms in comparison to their bodies than humans/elves/dwarves/hobbits, and sometimes the bigger ones need to do this in order to quickly move through tunnels with low ceilings, as their race is subterranean by inclination.
The Woggle-Bug in The Wizard of Oz series would walk on two legs, as he felt it was more civilized, but would revert to four legs when he was scared and needed to run faster.
In the Harry Potter series, the werewolf Fenrir Greyback does this... while in human form.

Live Action TV

There's a variant in Lexx, where Xev is able to curl up like a wheel and roll rapidly, because she's become part cluster-lizard and that's their method of locomotion.
The heroes of Hyakujuu Sentai Gaoranger run on all fours when chasing an enemy. Also used in the adaptation Power Rangers Wild Force, yet downplayed because all of them got Cool Bikes (as opposed to Gaoranger where only the Sixth Ranger had a bike).

Video Games

In Lugaru the Player Character can do this. Justified, since he is a rabbit, although normally bipedal.
The Stranger from Oddworld: Stranger's Wrath starts loping if he runs for long enough. It's actually rather impressive considering the fact that Stranger's true form is that of a centaur-like creature.
The animal dash ability in Tomba allows the titular character to do this.
The protagonist of Prehistorik Man runs on all four.
In Kingdom Hearts II, protagonist Sora does this in Anti-Form.
The Worgen in World of Warcraft usually walk around on two legs, but go to all fours when they need to move fast. The playable Worgen have this instead of a racial mount.
The Fast Zombies from Half-Life 2, which have long fingers to seemingly support this.
Cave woman Ayla runs this way in Chrono Trigger.
As in the anime and manga section, Pikachu can function equally well on either four or two legs - when they're in 3D, they're shown to run on four and walk on two.
City of Heroes features the purchasable power Beast Run which allows a character to do this.

Web Comics

Florence in Freefall switches to quadruped when running, because she's a wolf. She actually grew up as a quadruped and then had to adapt to standing upright as an adult.
El Goonish Shive. During the "Painted Black" arc, while Grace is infiltrating Damien's underground lair she encounters Vlad and tries to run away from him. While in her half squirrel/half human form she gets down on all fours like a squirrel to run away from him.

Web Original

The MS Paint Fan Adventure Water Works has Slick do this with his arm and leg blades. He explains it's faster than walking, but considered rude as you damage people's floors"
Shia LeBeouf in Actual Cannibal Shia LeBeouf
In the web animation for BT21 RJ (and by extension all civilized alpacas) stands in two legs but runs in four when wanting to run really fast.

Western Animation

Rigby from Regular Show when he needs to move quickly.
Zeke the Big Bad Wolf from the Silly Symphonies cartoon, Three Little Pigs is normally a bipedal half-dressed Funny Animal, but at the end of the cartoon, he becomes completely naked, assumes a four-legged stance, and runs away.
The Gargoyles often do this when they're in a hurry.
Nightcrawler in X-Men: Evolution is occasionally seen running on all fours, usually when he's in an urgent situation.
The Thunderkittens in ThunderCats (2011).
Aisling from The Secret of Kells sometimes runs the same way in her human form as in her wolf form.
Fifi LaFume from Tiny Toon Adventures sometimes does this.
Wakko Warner from Animaniacs and would do this a few times as well.
Pinky the tall mouse from Pinky and The Brain would run in his hamster wheel like this.
Spike from both the original My Little Pony and Friendship is Magic is occasionally seen doing this.

Real Life

Most children have to learn to go up stairs without using their hands.
Some adults can pull it off better than others.
In documented cases of human children being raised by wild animals like wolves, or in one case, gazelles, they are often found being able to run perfectly well on all fours.
Inverted by some lizards, which walk on four legs but rise up on their hind legs to run.