The Unsuicidal Lemming

The Unsuicidal Lemming

In 1967, on a balmy spring day in Alaska, millions of burrowing hamsterlike rodents emerged from the ground. No one walking in the area could avoid stepping on the ground cover of squeaking lemmings. As if seized by mass madness, the animals assembled into a horde stretching for miles and rushed straight across the Alaskan tundra for nearly 125 miles. At a steep cliff near Point Barrow, the endless ranks plunged into the cold Arctic Ocean. The frigid water became the grave for the millions of lemmings that completed the trek. Witnesses insisted they were committing suicide. And so it would appear.

These rushes into the sea have provided the occasion for many lemming legends, particularly in Norway. The lemmings, the Norwegians maintain, are obeying an instinct to migrate to sunken Atlantis, or even to an ancient Greenland supposedly connected to Scandinavia in the geologic past. In earlier times people believed that lemmings fell from the sky like rain. How else could one explain the fact that suddenly the land was covered with hysterical, squeaking lemmings scurrying to nowhere?

Attempts have been made to predict the "lemming year," the cycle of population surges, as every seven, five, or three years. But the irregular explosions seem to follow several years of ideal weather conditions that produce increased vegetation and, therefore, lemmings aplenty.

Normally a small, inconspicuous animal, the lemming is a common rodent throughout the northern latitudes of all continents. Four to six inches long, with an inch or less of tail, thick, water—repellent coat, blunt muzzle, small eyes, and ears hidden under fur, it is well built for resisting cold.

In the summer, lemmings feed well on the abundant mosses, lichens, and other arctic vegetation. They store additional leaves and roots in holes and crevices between rocks. Rather than hibernating in winter, they dig shallow burrows in the ground or, if the earth is frozen, just under the snow. In the fall a long digging claw grows out from under the normal claws of each foot so they can cope with the digging demands of a frozen landscape. They live off roots, stems, and underground moss along with the food stored during the summer.

Large colonies of lemmings live together, congested but snug, and safe from foxes, lynxes, weasels, wolves, owls, ravens, hawks, and other predators. Breeding continues almost uninterrupted, and the winter season produces several litters. In spring digging claws are shed, and the lemmings leave their snow burrows. The complicated maze of well—trodden snow and ice that formed their tunnels is often the last thing to melt, leaving a lacy network of ice as a spring decoration.

Lemmings are prodigious producers. The average lemming litter has five or six young, and five or more litters may be born to a single female in one year. Although most mothers deliver their first young at age four to six months, they have been recorded as giving birth when 39 days old. Gestation taking about three weeks, the precocious mother would have become pregnant at the age of 20 days. With no reproductive controls and with several females from the first and second litters adding their families to the heap, the population grows explosively. And explode it does!

By late spring the passages of the underground burrows have become choked with lemmings. Roofs and walls cave in when their city can no longer accommodate the swarming crowds. Clamoring for space, the normally docile lemmings become aggressive toward each other; fights break out incessantly, and bickering and biting are everyday occurrences. Finally each animal obeys the impulse to get away, and "refugees" emerge from every burrow. Within a few hours they have eaten all the vegetation in their area and begin to mill around in wild confusion, gripped by panic. They run and leap in all directions, squeaking, barking, and gnashing teeth.

Eventually one lemming will cross a frontier that had been the outer limit of their world. Others follow until millions congregate into an enormous throng. They advance arbitrarily in all directions. They climb down mountains, only to meet another procession of lemmings climbing up. By some grim paradox, each lemming, at the onset of the migration, is obeying an unconscious instinct to flee from its perilously increasing numbers, but the migrating masses unwittingly take their problem with them.

During the march, the lemming becomes aggressive out of all proportion to its size, even to humans it may encounter. It will square off at a passerby, uttering doglike barks, gnashing its teeth, and biting. The stubborn little rodent holds its ground against any adversary, snarling and biting at a fox or weasel intent on making it the next meal. At times so many lemmings are killed by automobiles and railroad trains that massive removal of bodies by the National Guard becomes necessary for basic sanitation.

Individual hordes, sometimes over a hundred miles long, tend to move in a straight line toward some point on the horizon. Passing through villages, they run through rather than around any structure that is accessible. Human occupants must watch helplessly from a rooftop until the throng has passed and even more helplessly as it ravages newly planted crops. Those aware that this is a "lemming year" delay planting until after the caravan has moved on. Lakes and rivers are no problem; the lemmings, excellent swimmers, paddle across. Should a small boat happen in their path, they will climb aboard on one side and jump overboard on the other while the human occupants try to remain inconspicuous.

For almost all of the remaining lemmings, the expedition is over when they perish from stress, exhaustion, hunger, or predation. They have inadvertently provided a bounteous feast for all carnivores, including birds of prey and even fish during their march. The number of lemming marchers has been reduced many thousandfold by the time the obsessed travelers reach the seacoast. They plunge into the surf, swimming in dense squadrons farther and farther out toward that spot on the horizon. Mariners miles from land have reported that their ships appear to have run aground on what looks like a solid furry landmass of lemmings that extends for miles. The little rodents, kicking and paddling, swim continuously toward some vague paradise. Eventually they reach eternity.

The lemmings, of course, are not trying to commit suicide. They are merely searching for food and living space and carry their search to its inevitable conclusion.

There are exceptions. Some lemmings, observing the mass flights from their native habitat, recognize that the situation at home is correcting itself, and they stay right where they are. Other restless migrants occasionally have the good fortune to come upon territory suitable for their needs. For these lucky few the migration is over. They are the dropouts who can begin a new life.

Massive population explosions that drive most of a species into a frenzied march toward death seem to serve no purpose. But the lemmings that remain from one explosion seem to be stronger, calmer, and better able to resist the migratory impulse. They are the new generation that will prosper when the plague of overpopulation has subsided. This appears to be a graphic example of natural selection and the survival of the fittest. Also, the lemmings can provide the human race with the merciless example of the catastrophic madness to which an exploding population can be driven. Somehow the resemblance to the teeming human multitudes scuttling aimlessly about the world's cities in mass confusions and self—destruction is not easy to ignore.

From the book: 
Petrified Lightning