Editing Swarm behaviour (section)

==Myths==

* There is a popular myth that [[lemming]]s commit [[mass suicide]] by swarming off cliffs when they migrate. Driven by strong biological urges, some species of lemmings may migrate in large groups when population density becomes too great. Lemmings can swim and may choose to cross a body of water in search of a new habitat. In such cases, many may drown if the body of water is so wide as to stretch their physical capability to the limit. This fact combined with some unexplained fluctuations in the population of Norwegian lemmings gave rise to the myth.<ref>{{cite web |url=http://www.wildlifenews.alaska.gov/index.cfm?adfg=wildlife_news.view_article&articles_id=56&issue_id=6 |title=Lemming Suicide Myth Disney Film Faked Bogus Behavior |first=Riley |last=Woodford |url-status=unfit |archive-url=https://web.archive.org/web/20100103112042/http://www.wildlifenews.alaska.gov/index.cfm?adfg=wildlife_news.view_article&articles_id=56&issue_id=6 |archive-date=January 3, 2010}}</ref>
* [[Piranha]] have a reputation as fearless fish that swarm in ferocious and predatory packs. However, recent research, which started "with the premise that they school as a means of cooperative hunting", discovered that they were in fact rather fearful fish, like other fish, who schooled for protection from their predators, such as cormorants, caimans and dolphins. A researcher described them as "basically like regular fish with large teeth".<ref>[https://www.nytimes.com/2005/05/24/science/24obse.html?_r=1 Red-Bellied Piranha Is Really Yellow] ''New York Times'', 24 May 2005.</ref>