Lemmings are friendly rodents (unless you saw them in your kitchen) that have carried an urban legend about their behavior for decades. It has always been believed that these animals commit mass suicide when their population is excessive compared to their resources, thus facilitating the survival of the young, but it is not true. And all the blame is on a Disney documentary from the 1950s.
The documentary, called “White Wilderness”, showed the life of these small rodents in their natural habitat. In it you can see how many of them commit suicide by jumping off a cliff, thus corroborating what everyone believed about them. The problem comes when it was discovered that those responsible for the filming not only manipulated some shots to make it appear that they were thrown into the void, but that they themselves pushed the animals to the edge of a cliff so that the cameras could capture their supposed suicide.
Lemmings don’t actually commit suicide when they are densely populated, but simply migrate in search of new resources. Logically, many of them die on the way from hunger, the attack of predators or accidental falls, but the cause is far from being suicide.
Apparently, when the members of the documentary discovered the reality (that they were not committing suicide), instead of spoiling the entire investment and staying without recording, they preferred to invent it to their liking. If Mickey Mouse finds out …
Although the theory of mass suicide was older, the documentary was the determining point for it to be taken as law. In fact, several decades later, in the 90s, a video game called Lemmings became very popular, which consisted of saving the maximum number of them using some orders that they had to fulfill, among which was self-immolation or, directly, suicide.
Here, the famous Disney documentary that, by the way, won an Oscar.