this keeps happening
A Brief History of Bad Ideas
The hippo bill was not some lonely act of madness. It belongs to a proud tradition of looking at a problem, importing an animal to fix it, and then spending the next century regretting it.
The all-stars of unintended consequences
Cane toads in Australia
About a hundred cane toads were shipped to Queensland to eat the beetles wrecking the sugarcane. The beetles lived high on the stalks, out of reach, so the toads ignored them and bred instead. They are poisonous, they have no local predators, and there are now upward of 200 million of them still spreading across the continent, poisoning everything that tries to eat them.
Mongooses in Hawaii
Plantation owners brought in the small Indian mongoose to kill the rats in the cane fields. One catch: rats are nocturnal and mongooses are not, so the two barely crossed paths. The mongoose, left without rats, devoured native ground-nesting birds and turtle eggs instead. Kauai stayed mongoose-free and is quietly grateful.
Starlings in New York
A man named Eugene Schieffelin released around 60 European starlings in Central Park, and another 40 the next year. Those birds founded the entire North American population, which peaked near 200 million and remains a major agricultural pest, though numbers have fallen by about half since the 1970s.
Asian carp in the US
Imported to clean algae out of southern fish ponds and sewage lagoons. Floods let them escape into the Mississippi, and they have been muscling up the river system toward the Great Lakes ever since. Silver carp also leap out of the water at the sound of a boat motor, turning a quiet day on the river into a contact sport.
Nutria in Louisiana
The local entry. South American rodents brought in for fur, escaped, and now eating the marsh to death and speeding the state's coastal collapse. They were even floated as a way to control invasive plants, including water hyacinth. Setting one invader on another. Sound familiar?
Rabbits in Australia
A landowner released two dozen rabbits for hunting, a touch of home rather than a fix, and they spread about 100 kilometers a year, the fastest known mammal invasion ever recorded. The country built a thousand-mile fence to stop them. The fence did not stop them.
not quite the same
The escapees, for the record
A couple of famous invasions get lumped in here but belong in a slightly different bin. Nobody imported these to fix anything. They simply got loose.
Burmese pythons in the Everglades
Pets that were released or escaped, with a 1992 hurricane often blamed for freeing a facility full of them. However it started, they have collapsed the Everglades' mammals, with raccoon and opossum sightings down around 99 percent in the worst-hit areas.
The cocaine hippos of Colombia
The most on-the-nose example we have, and it gets its own full treatment on the what-if page. Four hippos, a private zoo, a dead drug lord, and an invasive herd nobody can get under control. It is the hippo bill come to life, just one country south.
keeping it honest
Two stories everyone overcooks
Hold on, that one is a myth
Kudzu, the vine that ate the South, mostly did not eat the South. It was pushed hard for erosion control in the 1930s, and it is real and invasive, but the legend wildly overstates how much ground it actually covers. It thrives on sunny roadsides where everyone can see it, which makes it look far more dominant than it is.
Hold on, that one is a myth
The beloved tale that Schieffelin released the starlings to bring every bird mentioned in Shakespeare to America has no evidence behind it. The story first appears in the 1940s, decades after his death, as one naturalist's guess. His own obituary mentions the starlings and says nothing about the Bard.
the moral
The pattern is the point
Every one of these started as a reasonable-sounding plan pitched by confident people. Eat the beetles. Kill the rats. Clean the ponds. Control the weed. The animal always had its own agenda. The hippo bill is the one that got away, the rare case where the confident people were stopped before the animal could write the ending. Given the competition on this page, that is a genuinely happy outcome.
The takeaway
If you ever find yourself in a hearing room arguing that the solution to your problem is a large foreign animal, this page is your sign to go home. The animal does not care about your plan. The animal has never read your plan. The animal is going to do whatever it wants, and there will be a great deal more of it next year.