Zane White, of Balclutha Primary School, asks :-

Why do lemmings run and leap off a cliff and kill themselves?

John Parkes, an ecologist at Landcare who advises conservation groups around the world (USA, Mexico, Chile, Argentian, Australia, many Pacific countries) on how to remove pests from islands, responded.

Lemmings are a group of small rodents that live around the arctic from Scandinavia across Russia to North America. They are in a group of animals called microtine rodents that include voles and muskrats. There are many lemming species grouped into six genera.

Like many small mammals, some lemming populations have a boom and bust life cycle. There is considerable scientific debate as to why many lemming species, particularly in the north of their range, appear to explode in numbers every 3 or 4 years, but one consequence of such an explosion in numbers is that the animals become obvious as they are forced to disperse in search of food. Lemmings can swim and will cross rivers and small lakes when dispersing, but are not very good at it and normally avoid water.

In 1958 Walt Disney made a film called Wild Wilderness about the arctic. This was filmed in Alberta in Canada but the lemming sequences pretended to be about the Norway lemming and showed spectacular shots of lemmings jumping to their deaths off a cliff. The pretence about the lemming species was not the only one in the film. The film company apparently paid Canadian children to catch the local lemmings which were then pushed over the cliff with the claim that the rodents ‘commit suicide’ – a myth was born. Animal ethics was not an issue in Hollywood in those days!

Interestingly, there are animals that, in a way, do ‘commit suicide’. The most extreme is that of the males of the small Australian marsupial Antechinus which die after they breed and before their offspring are born. Bad luck for the males but it does mean they do not compete for food with their mates or young.