Cane toads are an example of an intentional species introduction turned invasive

Most invasive species are spread accidentally by human activity

In the Florida Everglades, Burmese pythons were only found as pets in the 1980s, but their escapes and releases since then have led to a population of hundreds of thousands as of 2024. The spotted lanternfly—native to Asia—was first detected in Pennsylvania in 2014 and has since spread to about 20 states by hitchhiking.

Benign species can become invasive if introduced into predator-free habitats

Most ecosystems contain organisms that, over many generations, have evolved into a stable balance with one another and their surroundings. In a new environment, a species may no longer be restricted by the limiting factors it is used to, and the native organisms in the area may not adapt quickly enough to the invader to establish a new balance.

Poison frogs get their toxins from eating insects and mice

Other animals, including royal ground snakes, are able to survive eating poison. Scientists study the creative antitoxin defenses in these animals to discover treatments for poisoning.

Humans may be the ultimate invasive species

Originating in East Africa, Homo sapiens migrated across the world beginning about 60,000 years ago and directly harmed countless species by consuming resources and modifying ecosystems to serve our needs. While meeting the definition of an invasive species, some ecologists argue the opposite, claiming that humans have helped preserve numerous species.

From 1970 to 2017, invasive species have caused $1.28T in damage globally

The costliest species were the Asian tiger and yellow fever mosquitoes ($149B), which arrived in the US from Asia and sub-Saharan Africa, respectively. The bulk of their damage came from their transmission of diseases such as Zika, chikungunya, and dengue. (Some readers may experience a paywall.)

How scientists know invasive nutria were likely introduced to California by humans

Although native to South America, DNA testing of the semiaquatic rodents showed they are closely related to a population in Oregon, suggesting they were deliberately transported into the state. First identified in the San Joaquin Valley in 2017, the distance, terrain, and lack of nutria between the two regions has allowed researchers to rule out natural migration.

Feral and free-ranging cats rank among the most harmful invasive species

Transported across the planet by humans, cats can now be found in many environments and are estimated to kill about 2 billion birds each year in the US. Studies suggest cats have contributed to the extinction of at least 63 species worldwide.

An invasive, tree-killing beetle may threaten large swaths of Australia

A Curtin University study warns that large parts of Australia, including major cities and farming regions, could be highly vulnerable to the fast-spreading polyphagous shot hole borer, which releases a fungus that can starve trees of nutrients. The tiny insect has already caused severe damage across the Perth metropolitan area.

How we helped make Aedes aegypti mosquitoes such a problem

Mosquito genome sequencing data suggests that Aedes aegypti mosquitoes first started specializing on human blood around 5,000 years ago—when climates shifted and humans started domesticating plants in Africa and stored large amounts of water that may have attracted the bugs.

Distinct plant species evolved to produce caffeine as a pesticide

Although it provides a defense against insects trying to eat caffeine-bearing plants, the molecule is an example of exaptation, where its original function was repurposed over time. Studies show that some plants now produce caffeine-laced nectar to help pollinators move more quickly and pollinate more efficiently.

Fungi have been used to restore island habitats in the central Pacific

After removing 1.5 million invasive coconut palm trees and eradicating the black rats that fed on them, as well as seabirds and crabs, conservationists working with the US Fish and Wildlife Service identified areas where fungi could be transplanted to provide nutrients to native trees. These trees serve as nesting sites for seabirds whose guano nourishes coral reefs.

Invasivorism is a form of ethical eating focused on eating invasive species

The culinary approach helps combat the growth of invasive species populations by increasing demand for dishes made with them, but some suggest that creating a market for these species may help prolong their presence by moderating control. Some diners have expressed reluctance toward consuming more exotic species, such as nutria—raccoon-sized rodents.

Cross-species transplantation has been attempted in medicine for more than 300 years

Early reported xenotransplantation attempts included 17th century efforts in France to transfuse blood from animals into humans. The poor results prompted France to issue a xenotransplantation ban. In the 19th century, researchers tried animal-to-human skin grafts from species including sheep, rabbits, dogs, cats, rats, chickens, and pigeons.

Canine inspectors can help detect potential carriers of invasive insects

At ports of entry in the US, Customs and Border Protection agents use dogs to sniff for forbidden foods and other items that are known to harbor invasive pests. Agents also physically inspect items such as flowers to prevent entry by species that may harm US agriculture.

More than half of the 7,000 'kissing bugs' locals sent to Texas A&M University had parasites

Texas A&M University scientists began a community science program in 2012 asking people to send in kissing bugs (any of the 11 species of bugs potentially infected with Trypanosoma cruzi parasites). About 1,500 people sent in over 7,000 bugs for scientific research, and about 55% of the bugs were infected with the parasite that causes Chagas disease.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

Salvador Dalí had pet anteaters he (supposedly) took on walks

Known for his adept and weird public relations stunts, Dalí kept exotic pets, such as an ocelot named Babou, as well as anteaters. The insectivorous mammal accompanied him on walks (though it may have just been for a photo op) and on talk show appearances.

In the 1930s, three Australian soldiers were sent to fight emus with machine guns—and lost

As part of a post-WWI initiative to turn veterans into farmers, soldiers were given plots of land. After emus were found damaging the farmland, three men were sent to handle the flightless birds. These men ended up losing to the second-largest bird species in the world and potentially exacerbating crop losses by sending swaths of the birds running and trampling over wheat.

A Florida nuclear power plant canal system hosts the highest density of crocodiles in North America

Biologists have become regular fixtures at Turkey Point Nuclear Plant, where crocodiles found refuge after Florida's population boom pushed them out of coves and mangrove swamps. Teams working on the plant have done their part to modify the land and help the species thrive.

There are at least 6 fascinating examples of mind-controlling parasites

Parasitic organisms—including flatworms and barnacles, not just fungi—can modify animal behavior. They can give rise to dancing fish, pulsating snails, suicidal rats, and more. Though some of these pathogens can sicken humans, there is no strong evidence that any can control human behavior.

How the cicada entered popular music

For significant swaths of the country, cicadas are a calming summer soundtrack. In the past few decades, though, the insects' distinct sound have also entered the music world, providing drone and ambience for a range of musicians.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

At one point in the 20th century, more than a million Americans had pet monkeys

This choice to domesticate monkeys proved to be trickier than expected, and thus isn't a very appealing option for humans. Monkeys breed more slowly than other animals, while also being susceptible to diseases and challenging to contain.

Fossilized bite marks suggest some dinosaurs may have engaged in cannibalism

An excavation site near the Colorado-Utah border contained Allosaurus bones with tooth marks of other Allosaurus, which may have occurred in response to a dry season in the area. The Tyrannosaurus and Majungasaurus have also been shown to eat their own.

These cells 'taste' danger, trigger immune responses

Taste receptor-coated tuft cells are found throughout the body, where they communicate with and take part in a growing list of biological processes. In the intestines, these taste receptor-studded cells can sense byproducts of parasite metabolisms. This causes the taste receptors to release chemicals that alert the immune system, order nearby goblet cells to produce mucus, and trigger muscle contractions in attempts to launch the parasites from the intestines.

In 1892, two scientists purposefully infected themselves with cholera bacteria

When they became ill—one with mild diarrhea and the other with severe cholera—researchers pointed to that as proof that the pathogen caused the disease.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

See these 16 pieces of art evoking phobias of snakes, flying, spiders, and more. 

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Graffiti dates back to at least ancient Pompeii, where citizens scrawled messages to one another on public walls