In 1921 a Russian naturalist named Uvarov solved the mystery. Locusts are grasshoppers: they are the same animal. Swarms of locusts are ordinary grasshoppers gone berserk. If you take ordinary grasshoppers of any of several species from any of a number of the world’s dry regions—including the Rocky Mountains—and rear them in glass jars under crowded conditions, they go into the migratory phase. That is, they turn into locusts.
