Lemmings are legendary creatures. They live in the cold tundra where their stocky bodies, dense fur, short limbs, small hidden ears, and a stubby tail all help to minimise heat loss in the freezing conditions. Every three to four years, food becomes plentiful and numbers surge. When local food runs out, thousands leave their territory and go looking for new ground.
Hunger and overcrowding drive these migrations, and high density makes them chaotic. When the front of the group meets a steep slope, a rocky cliff or a wide river, momentum and panic take over. Individuals at the edge get pushed over by the weight of numbers behind them.
Lemmings can swim. What they cannot do is judge the width of a lake or an ocean inlet before they commit. Many drown from exhaustion, still swimming toward a far shore they mistook for the near bank of a stream.
What lemmings do not do is commit mass suicide by intentionally jumping off cliffs. The idea is a persistent myth driven by natural migration hazards and a famous Disney nature documentary White Wilderness filmed in 1958.
To get the footage to look like intent, the filmmakers bought imported lemmings in Canada and set them on snow-covered turntables to fake a stampede. Then they pushed them off a cliff into a river and filmed them falling.
Lemmings are driven by instinct to disperse and find resources. That is not the same as a biological urge for self-destruction, making this week’s insight all about not following the herd.
