Buzz
Could there be anything more terrifying on Earth than swarms, masses, or hordes of insects? These creatures are known by many names, most of which carry negative connotations—pests, creepy crawlies, no-see-ums, and more.
Their simplicity is truly remarkable. They're hundreds, even thousands of times smaller than humans, yet when they come together in overwhelming numbers, we find ourselves completely outmatched.
10. The Wonder of the Gulls
This tale is among the most renowned in Mormon history, recounting a ‘Biblical’ plague of crickets, known today as Mormon crickets, that descended upon the Great Salt Lake region in 1848. That year, Brigham Young led the Mormon settlers into Utah, and after a mild winter, they were hopeful for a bountiful harvest. Unfortunately, insect swarms posed a serious threat to their survival, and the unseasonably warm winter meant that spring and summer pests, ranging from insects to snakes, had not been killed off by the cold. Even larger, more dangerous creatures like cougars expanded their territories in the milder winter months.
Mormon crickets are actually a type of large katydid. They grow up to 7.5 centimeters (3 inches) in length, capable of pinching but not biting, and they cannot fly, making their swarming behavior all the more remarkable. While they often swarm across the Southwestern United States, the swarm in 1848 is thought to be the largest ever recorded. The Mormon pioneers likely would have faced devastation—had it not been for a similarly ‘Biblical’ arrival of seagulls. California seagulls, which are abundant around the Great Salt Lake, are large enough to thrive in the area. According to settlers’ diaries and newspapers, despite their despair over the cricket infestation, the settlers prayed for help, and a massive flock of gulls appeared in the sky, descending to devour all the crickets.
9. The Annual Red Crab Migration on Christmas Island
This event is considered a remarkable phenomenon of nature. Every November, in alignment with the full moon, millions of red crabs from Christmas Island make their way to the shore to lay their eggs, only to return to their burrows once the job is done. The island spans 135 square kilometers (52 square miles), and estimates suggest that the crab population ranges between 43 and 100 million. If the thought of an island completely covered by crabs unnerves you, take comfort in the fact that Christmas Island is 431 kilometers (268 miles) away from the nearest landmass.
Virtually no species of crab can be considered harmless. The red crab typically has a carapace of 11 centimeters (4.5 inches), and its pincers are strong enough to cut human skin. When they move in large numbers, it becomes impossible to walk among them without stepping on some or having them crawl over you, making the island look as though it's ‘bleeding’. Fortunately for the crabs, the entire island is an Australian nature reserve, and human activity is prohibited during the migration. Recently, the crab population has suffered a dramatic decline of 10–15 million due to the invasive 'yellow crazy ant.'
8. The Oklahoma Cricket Invasion of 2013
Ten thousand crickets may sound like a lot, but the actual number was estimated to be in the billions. Shoppers had to navigate under crickets that crawled on the ceilings of gas pump canopies. The sound of people running was likened to walking on crackers. Local expert Brian Jervis noted that they first appeared in unusually large numbers in September 2012, faded over winter, and then reappeared in even greater numbers the following summer. This was likely due to a prolonged dry spell in spring, followed by a wet period in June and July that softened the ground and made egg-laying much easier. Residents were urged to turn off outdoor lights at night, seal air conditioning vents, and rush in and out of their homes quickly. Even so, the stench from the dead crickets became unbearable.
The stench from the decaying crickets became so overpowering that it caused nausea throughout the affected areas.
7. The Asian Giant Hornet Claims 42 Lives in 2013
The Asian giant hornet has become somewhat of an Internet sensation. While many have heard about it, most people, unless they are in China or Japan, haven't seen one firsthand. Those who have, however, describe it as a true nightmare. Though not particularly aggressive, the Japanese subspecies, often called the 'sparrow bee,' can grow as large as a hummingbird, measuring 4 centimeters (1.5 inches) in length. Their stinger’s external segment is a quarter of an inch long, and their mandibles are powerful enough to decapitate honeybees, which they do to feed on their larvae. While their defense mechanism against large animals near their nest is no more aggressive than that of other hornets or wasps, their sting can be deadly, even for those who don’t have allergies.
The sting is notoriously painful, often compared to the feeling of a nail heated with a blowtorch being twisted into your flesh. Capable of flying at speeds of up to 40 kilometers (25 miles) per hour, they can cover distances of up to 100 kilometers (60 miles) in a single day. Their venom contains mandaratoxin, a highly potent substance capable of dissolving flesh, and the wounds from their stings are large, resembling bullet holes. Between July and October 2013, a single outbreak in Shaanxi Province, China, led to the death of 42 people. Additionally, 206 people in three cities were hospitalized. When injected in large quantities, the venom can cause kidney failure—one victim required 200 stitches and 13 dialysis sessions.
6. Killer Bees
Commonly known as 'killer bees,' Africanized honeybees are visually identical to the European honeybee subspecies. However, unlike European bees, disturbing a killer bee hive can be as dangerous as playing Russian roulette, as these bees need very little provocation to become aggressive. While a lawnmower 50 meters (150 feet) away typically wouldn’t trouble European bees, killer bees would perceive it as a threat and attack. Most people can’t outrun a honeybee, but killer bees fly at speeds of 19-24 kilometers (12-15 miles) per hour and will chase you for several hundred meters. While their venom is no more dangerous than other honeybees, their aggressive, coordinated attacks make them far more lethal. Finding shelter inside is usually effective, but it’s wise to close all windows.
This kind of nightmare scenario occurs more often than one might expect. On average, about 40 people in North America fall victim to killer bee attacks each year. On June 3, 2013, in Moody, Texas, Larry Goodwin accidentally disturbed an abandoned chicken coop with his tractor while clearing brush, and 40,000 bees swarmed out. He attempted to escape in his tractor, but eventually had to jump out and run toward a garden hose to spray the bees away until his neighbors could take shelter indoors. A woman who tried to help was stung repeatedly and forced to retreat into her home. Volunteer firefighters who attempted to intervene with water cannons were chased off by the bees. Unfortunately, Goodwin did not survive.
The key distinction between Africanized honeybees and European honeybees is that only about 10 percent of a European hive will defend it when disturbed. In contrast, killer bees will send out a much larger portion of the hive, creating a much larger, more terrifying swarm. Like other bees, each killer bee dies after stinging, as their barbed stingers tear free from their bodies. However, these bees are so aggressive that they can even penetrate the protective clothing worn by beekeepers in order to sting them. No other species of bee is known to exhibit such behavior.
5. Mosquitoes That Drain Livestock of Blood
When mosquitoes form large swarms, the outcome is just what you’d anticipate. Unlike bees, which sting in defense, mosquitoes don’t attack unless provoked. A single bite from a mosquito is usually harmless, but it can transmit diseases like malaria. They don’t tend to take much blood before an alert person swats them away. Even a large mosquito can only consume one drop of blood, but when they gather in swarms of billions, the situation escalates, as occurred from August to late September 1980 on Stephen Perry's farm near Brazoria, Texas.
The swarm was triggered when billions of mosquito eggs, which had been dormant in the nearby marshes for 20 years, were flooded by saltwater tides. The saltwater was enough to activate the eggs, and once they hatched, billions of larvae turned into mosquitoes, attacking Perry’s livestock in synchronized swarms. Perry began finding dead cattle and horses around his property. Necropsies showed no external injuries, but sometimes half of the usual 7-9 gallons of blood was missing from the carcasses. Perry recalled being able to wave his hand above his head and bring down hundreds of mosquitoes. These swarms persisted for over a month, one after the other.
4. Monarch Migrations
Not all swarms evoke fear—some, like the monarch butterflies, create a sense of awe when they gather in the millions. These butterflies are unique among North American species for their bird-like migration, though they don't survive the journey. They embark on a long flight from as far as 4,000 kilometers (2,500 miles) away in Canada, heading south to Mexico. Along the way, females lay their eggs, and as they perish, the new generation continues their migration. These butterflies seem to be born with an innate understanding of the journey ahead.
Nearly all monarch species spend the winter in what is now protected as the Monarch Biosphere Reserve, located in Mexico's Michoacan region. This expansive forest, consisting of pines and oaks, covers about 138,000 acres. Each year, the monarchs restrict themselves to only 11.6 acres within this vast forest. They cluster together on the trees, resting on leaves, needles, bark, the ground, and even on each other, creating a spectacle resembling orange vines. When they take flight in unison, the sound they produce is said to resemble the soft patter of rain.
3. The Sadiya Tarantula Invasion
Spiders are usually solitary, due to their cannibalistic tendencies—members of the same species often end up devouring one another. No spider is willing to share space with another near its web, and even those that don't have webs refuse to tolerate the presence of others. As a result, swarming behavior is rare. Yet, on May 8, 2012, an outdoor festival in Sadiya, situated near the Himalayas, witnessed a truly bizarre event. A multitude of medium-sized tarantulas emerged from the hills, making their way into the streets, scaling walls, and even crawling onto the attendees.
Little is known about the swarm, but reports describe the spiders as 'highly aggressive.' They reportedly descended upon the town, leaping onto people and animals, biting them all over. It is said that two individuals succumbed to the bites. Initially, the victims sought treatment from local witch doctors, who made incisions in the bites, drained the blood, and cauterized the wounds. When this method failed, the victims turned to the hospital, suggesting that the cause of death was likely infection rather than the venom itself.
The swarm apparently disappeared as quickly as it had arrived, prompting arachnologists from around the world to rush into town to investigate the strange spiders. However, they were faced with an unsolvable mystery. Some specimens of the spiders were captured and seemed to be an entirely new species, possibly a hybrid. They displayed the aggressive temperament and physical structure of the notorious Sydney funnel-web, although this species is native only to Australia. Despite numerous efforts, the origin of the swarm remains unknown.
2. Migration of the Driver Ant
The driver ant, known as siafu, follows the philosophy of 'strength in numbers.' When their food supply dwindles, the colony relocates. Every living creature—whether insect, human, or elephant—must leave the area. These ants can float across rapid rivers by joining together in rolling balls and climb trees in search of food in the canopies. They navigate by using pheromones, as they lack eyes. If an animal ventures too close, a guard ant releases an alarm pheromone, causing the swarm to converge and attack. They kill large creatures by invading their lungs. Though they rarely sting, their massive jaws deliver fierce bites. These same jaws are used by natives in Africa and South America as makeshift stitches when conventional sewing tools are unavailable.
Ant migrations, though infrequent, happen about once every five years. These migrations are characteristic of almost all "army" ant species. The siafu is feared globally, often considered the most dangerous among them.
In Brazil and its northern neighbors, the species Echiton burchellii is prevalent. These colonies migrate periodically, never halting until they locate an area abundant in food. During these migrations, they build temporary camps, using their own bodies to form protective barriers around the queen and eggs. The ants create living walls made of their bodies, protecting themselves inside bushes and trees. Anything that disturbs their formation is met with savage attacks. While E. burchellii can cause pain with its bites, it lacks the ability to cut through human flesh like the siafu. However, it can attack the eyes and mucous membranes. There are over 50 species of siafu, with Dorylus molestus being one of the most famous. This species is often welcomed in African communities, as it helps control rats. Locals, however, must avoid them, as they are capable of consuming anything they can overpower. There are no documented cases of them killing elephants, though locals in the jungle regions claim to have witnessed such events. They are capable of biting through elephant skin.
1. Albert’s Swarm
One of the most remarkable historical insect swarms, the Rocky Mountain locust swarm remains the largest known gathering of any animal species in history. The locust species is now extinct, primarily due to farming practices like deep plowing, which later contributed to the Dust Bowl. This massive swarm struck western Missouri in April 1875. Albert Child, a doctor from Nebraska, observed the swarm and calculated its size based on its speed and the time it took to cross southern Nebraska. He estimated that the swarm covered an area of 513,000 square kilometers (198,000 square miles), larger than California. The swarm's weight was approximately 27.5 million tons, and it may have contained up to 12.5 trillion locusts. Like most locusts, they couldn’t bite, but they caused livestock to stampede and could even suffocate them by flying down their throats. These locusts devoured every leafy crop in their path.
The species vanished around the turn of the 20th century due to the destruction of its habitat, as the land was plowed, resulting in the loss of its buried eggs.
