The panic migration of the lemmings is triggered by a kink in the food chain.

During the years of abundance a female can produce four litters of eight young ones in a season. The usual

breeding rate is two litters of five.

The more than threefold population explosion causes acute shortage of food.

Huge groups of lemmings dash off in search of food. Most of them die on the journey.

They plunge over the hills into the rivers.

Many dive into the sea in their uncontrollable drive to find food.

Nature restores the balance by this drastic step.