Tripedalism

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Tripedalism (from the Latin tri = three + ped = foot) is locomotion by the use of three legs. There are no known naturally occurring three-legged animals, although the movement of some macropods such as kangaroos, which can alternate between resting their weight on their muscular tails and their two hind legs, may be an example of tripedal locomotion in animals. There are also the tripod fish. This fish rests on the ocean bottom on two rays from its two pelvic fins and one ray from its caudal fin ([1]).

A three-legged dog in south west England, injured in a road accident. The dog was running around at normal speed.

Tripedalism contrasts with the common bipedalism of two-legged animals and quadrupedalism of four-legged animals.

Quadrupedal amputees and mutations[edit]

There are however some three-legged creatures in the world today, namely four-legged animals (such as pet dogs and cats) who have had one limb amputated. With proper medical treatment most of these injured animals can go on to live fairly normal lives, despite being artificially tripedal. There are also cases of mutations or birth abnormalities in animals (including humans) which have resulted in three legs.

Use of tripedalism in science fiction and fantasy[edit]

Tripedalism is more at home within a science fiction or fantasy theme, such as where mysterious alien life forms walk upon three legs and on other worldly planets where all the Earthly conventions of two or four legged animals are vastly different.

  • John Wyndham's novel "The Day of the Triffids" (1951) had tripedal plants called triffids which walked around.
  • Pierson's Puppeteers are a tripedal alien race in the Known Space universe by author Larry Niven — they have two forelegs and a single hind leg ending in hooved feet and two snake-like heads instead of a humanoid upper body.
  • The Tripods, a trilogy of novels written by John Christopher, is a post-apocalyptic story set one hundred years after the invasion of Earth by tripedal aliens. The first two novels became the basis of a science fiction TV-series of the same name, produced in the United Kingdom in the mid-1980s.
  • In the computer game Half-Life (and its sequel Half-Life 2) there are numerous tripedal, alien animals seen throughout the series, including Houndeyes, as well as synthetic creatures created by the Combine called Striders and Hunters. Also, it is interesting to note there are a lot of bipedal, sentient, alien species in the game who have three arms, which may have evolved from a tripedal three legs.
  • In the Star Wars prequels, a battle droid is introduced called a destroyer (also known as a "droideka"), which has tripedal as well as rolling locomotion.
  • In the Pocoyo cartoon, tripedals are again the aliens (in this case, friendly).
  • In the 2012 video game Borderlands 2 there is a tripedal animal called Crystalisk.

Mythological tripedals[edit]

See also[edit]

External links[edit]

Illustrated research essay Three-Legged Animals in Mythology and Folklore.