# Why has no animal species ever evolved wheels? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [April 23, 2014, 11:40pm UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816 "2014-04-23T23:40:25Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![David\_Ehrlich](https://avatars.discourse-cdn.com/v4/letter/d/958977/32.png) [@David\_Ehrlich](https://boards.straightdope.com/u/David_Ehrlich)\ **Post date:** [April 23, 2014, 11:40pm UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816/1 "2014-04-23T23:40:25Z")
The problem with your CD example is that it not only lacks a fixed axle, but there’s no evident way to make the disc rotate. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [April 24, 2014, 2:01am UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816/2 "2014-04-24T02:01:25Z")
[Link to thread.](http://www.straightdope.com/columns/read/1151/why-has-no-animal-species-ever-evolved-wheels) Not so hard to imagine ones that could exist. The bottom line of the column though is a good one. Truth be told wheels are not so practical for the the variety of environments that most complex animals need to be able to traverse. You need to travel in trees? Wheels suck. Go up steep inclines? Better to have at least two feet. Get over logs and boulders in your path? Wheels not so good. Go up nature’s natural staircases? On wheels? The natural world is not best traversed with wheels. No selective pressure. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 24, 2014, 2:13am UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816/3 "2014-04-24T02:13:25Z")
Humans evolved wheels, they are secreted from our digital organs. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [April 24, 2014, 2:14am UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816/4 "2014-04-24T02:14:12Z")
Here is a better diagram of the rotating flagellum structure: > **[File:Flagellum base diagram-en.svg](https://en.wikipedia.org/wiki/File:Flagellum_base_diagram_en.svg)** > > Original file ‎(SVG file, nominally 629 × 561 pixels, file size: 121 KB) > Image moved from Flagellum base diagram.svg > A flagellum (plural: flagella) is a long, slender projection from the cell body, whose function is to propel a unicellular or small multicellular organism. The depicted type of flagellum is found in bacteria such as E. coli and Salmonella, and rotates like a propeller when the bacterium swims. > In some countries this may not be legally possible; if so: > LadyofHats grants anyone t... ---
**Author:** ![Vashbul](https://avatars.discourse-cdn.com/v4/letter/v/3d9bf3/32.png) [@Vashbul](https://boards.straightdope.com/u/Vashbul)\ **Post date:** [April 27, 2014, 6:09am UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816/5 "2014-04-27T06:09:24Z")
Why not have pairs of wheels, each pair would have one which contacts the ground and rotates, while the other lifts up off the ground and goes backwards, they take turns supplying locomotion and the axles (made of muscle) twist a turn or two and then reset? I could imagine that one evolving on a fairly flat sort of terrain. ---
**Author:** ![Blackfaer](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@Blackfaer](https://boards.straightdope.com/u/Blackfaer)\ **Post date:** [April 28, 2014, 12:01am UTC](https://boards.straightdope.com/t/why-has-no-animal-species-ever-evolved-wheels/686816/6 "2014-04-28T00:01:44Z")
> [@Vashbul](#): > > Why not have pairs of wheels, each pair would have one which contacts the ground and rotates, while the other lifts up off the ground and goes backwards, they take turns supplying locomotion and the axles (made of muscle) twist a turn or two and then reset? I could imagine that one evolving on a fairly flat sort of terrain. Sounds kind of like a foot…