When one thinks of a locust swarm we usually think of the Biblical Plagues, a divine intervention to punish humanity in a past far gone. But a more recent biblical plague played out in the Great Plains of the United States during the summer of 1875.
Keeping with the tales of the past, farmers watched in panic as the skies dimmed as trillions of locusts came over the horizon moving faster than any natural disaster. These insects moved so quickly that people literally had to run for shelter to escape the swarms.
Witnesses reported trees breaking under the weight of the insects and layers forming on the ground up to six inches thick. There were so many locusts that their brined and solidified bodies clogged the Great Salt Lake in Utah and formed walls six feet high extending two miles away from the lake. The swarm was speculated to contain more than 3.5 trillion locusts and span over 198,000 square miles, larger than the state of California.
The locusts destroyed crops, killed poultry that gorged on the insects, and infested the soil with the sheer number of eggs that were laid beneath the surface. But these swarms were not a punishment from God, but rather from a mutation that occurs when large numbers of grasshoppers are forced to live close to one another during times of drought.
The close living proximity causes changes in the types of eggs that the female grasshoppers lay. The nymphs that hatch out of the mutated eggs grow longer wings, tend to stay in large swarms, and even change in size and color. The result is a huge migratory population of locusts that no longer resemble their grasshopper parents.
Even more mysterious then the appearance of this locust swarm was its sudden disappearance. By the turn of the century the Rocky Mountain Locust had died off completely and they have not been seen alive since 1902, much to the relief of farmers everywhere.