A facinating list of common misconceptions. It is Wikipedia, but these misconceptions have the supporting data. http://en.wikipedia.org/wiki/List_of_common_misconceptions
"Lemmings do not engage in suicidal dives off cliffs when migrating. They will, however, occasionally, and unintentionally fall off cliffs when venturing into unknown territory, with no knowledge of the boundaries of the environment. The misconception is due largely to the Disney film White Wilderness, which shot many of the migration scenes (also staged by using multiple shots of different groups of lemmings) on a large, snow-covered turntable in a studio. Photographers later pushed the lemmings off a cliff" I REALLY hate Disney now. they're so freaking obsessed with death and tradgedy
