Mormon crickets are native to the rangelands of western North America, where they live among sagebrush and wildflowers across a surprisingly wide range of elevations and climates. Despite the name, they are not actually crickets. They’re shield-backed katydids (Anabrus simplex), and they’ve been part of the western landscape long before any human settlers arrived. The common name traces back to a single dramatic event in 1848 Utah, but the insects themselves come from a much broader swath of the American West.
Native Range and Habitat
Mormon crickets are found across 17 western states, from the low deserts of Nevada and Washington to the alpine tundra of the Rocky Mountains. Their core habitat is the open sagebrush-grass landscape of the Great Basin, the vast arid region stretching across Nevada, Utah, and parts of neighboring states. But they’re far from limited to that zone. In Colorado, small resident populations live in forest openings at 6,500 feet and above 11,000 feet in alpine tundra. Populations have been documented at elevations as low as 500 feet in the deserts of Nevada and Washington, and as high as 8,000 feet in the mountains of Montana and Wyoming.
This range spans dramatically different climates: from areas receiving just 6 inches of rain per year to those getting 20 inches, and from frost-free seasons as short as 30 days to as long as 180 days. That adaptability is part of what makes population explosions so hard to predict. The insects can persist quietly in many different environments, then erupt into enormous swarms when conditions align.
Why They’re Called “Mormon Crickets”
The name comes from an 1848 infestation in the Salt Lake Valley, when swarms descended on the crops of newly arrived Mormon settlers. California gulls swooped in and ate large numbers of the insects, an event the settlers viewed as miraculous. Entomologists later classified the species not as a cricket but as a katydid, yet the common name stuck. The “Mormon cricket” label has been in use ever since, even though the insects are found across the entire western U.S. and have no special connection to Utah.
Where Eggs Come From and How They Hatch
Female Mormon crickets deposit their eggs in soil, where they overwinter and sometimes remain dormant for far longer than a single season. In highland areas with cooler temperatures and more moisture, eggs can enter a state called diapause, essentially a pause in development, and stay underground for multiple generations without hatching. This means the “source” of a sudden outbreak may be eggs that were laid years earlier, quietly waiting in the soil.
In warmer, drier lowlands, eggs hatch and develop more quickly. But those same hot, dry conditions also kill a significant number of eggs before they ever hatch. The result is a delicate balance: rapid development versus high mortality in the lowlands, slow but steady survival in the highlands. When conditions shift, say a few wet years following drought, a large bank of dormant eggs can hatch simultaneously. That’s often how a landscape goes from having no visible Mormon crickets to being overrun with millions seemingly overnight.
What Triggers Mass Outbreaks
Scientists are still working to pin down the exact combination of environmental triggers that cause populations to explode. The general pattern involves a buildup of eggs in the soil over multiple years, followed by a season with the right temperature and moisture conditions to trigger a mass hatching. Because eggs can survive in diapause for so long, the “fuse” for an outbreak may be lit years before anyone notices.
Once populations are large enough, the insects begin forming migratory bands, dense groups of millions that march across the landscape. These bands aren’t random. Research published in the Proceedings of the National Academy of Sciences found that the marching behavior is driven by two specific nutritional deficiencies: protein and salt. When population density rises, local food resources get stripped. The insects become deprived of protein and salt, and they begin cannibalizing each other to compensate.
Cannibalism and the March
This is where the biology gets striking. Mormon crickets are, in the words of the researchers, “walking packages of protein and salt.” Their bodies contain exactly the nutrients that their hungry neighbors are craving. Cannibalism becomes rampant in dense groups, and individual crickets that stop moving are quickly eaten by those behind them. Experiments confirmed this directly: when researchers immobilized crickets within a marching band, those crickets were consumed.
So the mass marches that make the news are partly driven by each insect trying not to be eaten by the one behind it. Moving forward means encountering fresh habitat and food. Falling behind means becoming food. The presence of nearby crickets alone is enough to trigger increased movement in an individual, and the threat of cannibalism likely drives that response. Nutritional deprivation and cannibalism interact to create a self-reinforcing cycle of collective movement that can push bands across miles of rangeland.
Despite the dangers, there’s an upside to band membership. Grouping together provides protection from predators like birds, because any single cricket is less likely to be picked off in a crowd. The tradeoff is constant competition for food within the group. The march resolves that tension by continuously moving the group into new territory.
How Far They Travel
Mormon crickets cannot fly. Their wings are too small for flight, so they travel entirely on foot. Bands can cover significant ground each day, and over the course of a season, they may move across many miles of rangeland, farmland, and even roads. The sight of millions of large, dark insects crossing a highway is one of the more surreal experiences reported in rural western communities during outbreak years. Crushed crickets on pavement have caused roads to become slippery enough to cause accidents.
Where Outbreaks Hit Hardest
The states most frequently affected by large outbreaks include Nevada, Utah, Idaho, Montana, Wyoming, Oregon, and Colorado. The USDA’s Animal and Plant Health Inspection Service runs a rangeland suppression program specifically for Mormon crickets and grasshoppers across the 17 western states where they’re native. As of 2025, active environmental assessments for treatment programs were underway in Colorado and Utah, indicating ongoing concern about population levels in those areas.
The economic damage can be substantial. During a 1937 outbreak, crop losses reached $500,000 in Montana and $383,000 in Wyoming, figures that would be several times larger adjusted for inflation. Modern outbreaks threaten rangeland used for cattle grazing as well as crops, making them a concern for both farmers and ranchers. When bands move through an area, they consume sagebrush, wildflowers, grasses, and cultivated crops with little discrimination.
Not Crickets, Not Invaders
Two common misconceptions are worth clearing up. First, Mormon crickets are katydids, not true crickets. They belong to the family Tettigoniidae, the long-horned grasshoppers, and specifically to the subfamily of shield-backed katydids. They’re larger and bulkier than most familiar crickets, with adults reaching about two inches in length. Second, they’re not an invasive species. They’re entirely native to western North America and have been cycling through boom-and-bust population dynamics in this landscape for thousands of years. The swarms feel apocalyptic, but they’re a natural, if disruptive, part of the rangeland ecosystem.