# why do birds/ fish seem to turn and move as one, en masse? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [January 28, 2014, 1:03pm UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945 "2014-01-28T13:03:07Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![kerryraw](https://avatars.discourse-cdn.com/v4/letter/k/f05b48/32.png) [@kerryraw](https://boards.straightdope.com/u/kerryraw)\ **Post date:** [January 28, 2014, 1:03pm UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945/1 "2014-01-28T13:03:07Z")
Though I know this was questioned many moons ago, I recently came across the word to describe this phenomenon. It’s _allelomimesis_. From what I understand, new studies show that the most stable cluster sized is formed by a few individuals who are highly allelomimetic. > **[Cluster formation by allelomimesis in real-world complex adaptive systems](https://ui.adsabs.harvard.edu/abs/2005PhRvE..71d1905J)** > > Animal and human clusters are complex adaptive systems and many organize in cluster sizes s that obey the frequency distribution D(s)∝s-τ . The exponent τ describes the relative abundance of the cluster sizes in a given system. Data analyses reveal... > **[Allelomimetic behavior](https://en.wikipedia.org/wiki/Allelomimetic_behavior)** > > Allelomimetic behavior or allomimetic behavior is a range of activities in which the performance of a behavior increases the probability of that behavior being performed by other nearby animals. Allelomimetic behavior is sometimes called contagious behavior and has strong components of social facilitation, imitation, and group coordination. It is usually considered to occur between members of the same species. An alternate definition is that allelomimetic behavior is a more intense or more freque... ---
**Author:** ![C\_K\_Dexter\_Haven](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@C\_K\_Dexter\_Haven](https://boards.straightdope.com/u/C_K_Dexter_Haven)\ **Post date:** [January 28, 2014, 6:02pm UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945/2 "2014-01-28T18:02:17Z")
Welcome to the Straight Dope Message Boards, **kerryraw** , we’re glad you found us. For future ref, it’s helpful to other readers to provide a link to the column (or staff report) in question. Saves search time and tries to avoid duplication. No biggie, you’ll know for next time, and (as I say) welcome! Link to Staff Report (from 2004): [How does a flock of birds wheel and swoop in unison? - The Straight Dope](http://www.straightdope.com/columns/read/2151/how-does-a-flock-of-birds-wheel-and-swoop-in-unison) This was written by our resident ornithologist. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [January 28, 2014, 6:59pm UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945/3 "2014-01-28T18:59:12Z")
The short answer is that most lower animals and probably all life forms lower than that function more by algorithm than by anything like rational thought. While 100 humans might have a hell of a time doing instant simultaneous movements, you can devise a very simple algorithm that produces the behavior. ---
**Author:** ![burpo\_the\_wonder\_mutt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/burpo_the_wonder_mutt/32/365_2.png) [@burpo\_the\_wonder\_mutt](https://boards.straightdope.com/u/burpo_the_wonder_mutt)\ **Post date:** [February 5, 2014, 9:14pm UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945/4 "2014-02-05T21:14:43Z")
When I was in grammar school, we were told that birds have a tiny piece of lodestone in their heads and the minute magnetic fluctuations started by the lead bird caused them all to turn simultaneously. Sounds like magic; has this been rebuffed? ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [February 6, 2014, 1:53am UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945/5 "2014-02-06T01:53:13Z")
Birds can detect the magnetic field of the Earth, which is useful in long-distance navigation, but flocking behavior is based on reference to the two sides, which is where the eyes are. If you have ever had military training (even to the extent of being in a high-school marching band), you already know the basic secret—just keep the lines straight, and everything will work out. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [February 6, 2014, 2:28am UTC](https://boards.straightdope.com/t/why-do-birds-fish-seem-to-turn-and-move-as-one-en-masse/679945/6 "2014-02-06T02:28:23Z")
just keep an even distance then you can do curves in three dimensions too.