The insects commonly called “murder hornets” are northern giant hornets (Vespa mandarinia), the largest hornet species in the world. They made international headlines in 2019 when they were first detected in Washington State, sparking fears of an invasion that could devastate honeybee populations and pose a danger to humans. After a five-year eradication campaign, U.S. and Canadian authorities announced the hornets have been successfully eliminated from North America.
Why They’re Called “Murder Hornets”
The nickname took off in 2020 after media coverage of the Washington State detections. It stuck because of the hornets’ brutal method of attacking honeybee colonies and the roughly 40 human deaths they cause each year in Asia, primarily in Japan. The Entomological Society of America formally rejected the “murder hornet” label in July 2022, adopting “northern giant hornet” as the official common name. The USDA followed suit, noting that the sensationalized name fueled unnecessary public panic and didn’t reflect the insect’s actual risk to most people.
At the same time, two related species also received standardized names: the southern giant hornet (Vespa soror) and the yellow-legged hornet (Vespa velutina). The renaming was partly practical, since multiple hornet species were being lumped together in public conversation, and partly an effort to move away from a name that some felt carried xenophobic undertones given the insect’s Asian origin.
Size, Appearance, and Sting
Northern giant hornets are unmistakably large. Queens can reach about two inches in body length, with workers slightly smaller. Their heads are a distinctive orange-yellow, and their abdomens have alternating bands of dark brown and orange. The wingspan on a queen can stretch over three inches, making them easy to distinguish from native wasps and hornets if you know what to look for.
Their stinger is roughly a quarter inch long, far longer than a typical honeybee’s, and can penetrate standard beekeeping suits. Unlike honeybees, hornets can sting repeatedly. The venom contains a cocktail that destroys tissue at the sting site, which is why stings produce intense, lingering pain and significant swelling even in people who aren’t allergic. Multiple stings can cause kidney damage or organ failure regardless of allergy status.
How They Destroy Honeybee Colonies
What earned these hornets their fearsome reputation is their coordinated assault on honeybee hives. The attack unfolds in distinct phases. First, a scout locates a hive and marks it with pheromones. That chemical signal recruits dozens of nestmates to the target. Then comes the slaughter phase: a group of hornets, sometimes fewer than 30, can decapitate an entire colony of tens of thousands of European honeybees in a matter of hours. They use their large mandibles to clip the heads off defending bees one by one.
Once the colony is wiped out, the hornets occupy the hive and spend days feeding bee larvae and pupae to their own young. European honeybees, the species used in most commercial beekeeping, have essentially no defense against this. Asian honeybees, which evolved alongside the hornets, developed a remarkable counter-strategy: they swarm an invading scout in a tight ball and vibrate their flight muscles to raise the temperature high enough to cook the hornet alive. European honeybees lack this behavior entirely, which is why the hornets posed such a serious threat to North American agriculture.
How They Arrived in the U.S.
In December 2019, the Washington State Department of Agriculture verified two reports of northern giant hornets near Blaine, a small city on the Canadian border. These were the first confirmed sightings in the United States. Around the same time, Canada identified hornets at two locations in British Columbia. How they got there remains unclear, but the leading theory involves accidental transport in international shipping containers.
Through 2020 and 2021, both Washington and Canada continued to find new hornets. Tracking them was a painstaking process. Researchers trapped individual hornets, attached tiny radio transmitters to them, and followed them back to their underground nests. By the end of 2021, Washington State had located and destroyed four nests in Whatcom County, all within a few miles of the Canadian border. The effort was complicated by the COVID-19 pandemic, which limited fieldwork during the critical 2020 season.
The Eradication Was Successful
After five years of sustained trapping, monitoring, and nest destruction, USDA’s Animal and Plant Health Inspection Service and the Washington State Department of Agriculture announced that the northern giant hornet has been eradicated from the United States. No new detections occurred in the years following the 2021 nest removals, giving officials confidence the population was eliminated before it could establish a permanent foothold.
The success hinged on catching the invasion early. Community members reported sightings, researchers deployed thousands of traps, and interagency teams responded quickly when hornets were found. Officials noted they will continue monitoring for any future introductions, since the same shipping pathways that brought the hornets once could bring them again. But for now, northern giant hornets are not present in North America.
How Dangerous They Are to Humans
In their native range across temperate and subtropical Asia, northern giant hornets kill an estimated 40 people per year, mostly in Japan. During a particularly severe four-month stretch in China in 2013, the hornets caused 42 deaths and 1,675 injuries. Most fatalities involve people who stumble onto a nest or are stung many times, and people with venom allergies face the highest risk from even a single sting.
For perspective, honeybees and wasps collectively kill around 60 to 80 people per year in the United States. The northern giant hornet’s venom is more potent drop for drop, and it delivers more venom per sting, but the real danger comes from volume. A person who receives more than about 10 stings should seek emergency care, and anyone who experiences throat swelling, difficulty breathing, dizziness, or a rapid drop in blood pressure after any number of stings is having an anaphylactic reaction that requires immediate treatment with epinephrine.
For a single sting without an allergic reaction, cold compresses and over-the-counter antihistamines can manage the swelling and itching. The pain is intense but self-limiting. Watch the sting site for signs of infection in the following days, and keep in mind that any insect sting increases your risk of tetanus if you haven’t had a booster in the past five years.
Other Giant Hornets Still Worth Watching
While northern giant hornets have been cleared from the U.S., a related species is actively spreading. The yellow-legged hornet (Vespa velutina) was confirmed in Georgia in 2023, and unlike its larger cousin, it was detected after it had already begun reproducing. Yellow-legged hornets are smaller but are aggressive predators of honeybees and have already devastated bee populations across Europe since arriving there from Asia around 2004. They build large, visible nests high in trees rather than underground, making them somewhat easier to spot but harder to reach.
The yellow-legged hornet is now the primary invasive hornet threat in the United States. It poses a lower risk to humans than the northern giant hornet, with a less painful sting and smaller venom load, but its impact on pollinators and native insects could be significant if it becomes established across the Southeast.