What happens when we mess around with nature, trying to get it to do our bidding? Sometimes it works…but sometimes nature gets even. Here are a few instances when people intentionally introduced animals or plants into a new environment—and regretted it.
Import: English sparrows
Background: One hundred sparrows were brought from England to Brooklyn, New York, in 1850. Reason: to control canker worms that were killing trees in city parks.
Nature’s Revenge: The sparrows did their job—for a while. Then they got a taste for native insects, then they had a lot of babies, and then they took off. By 1875 the sparrows had made it to San Francisco, stealing nesting sites from native birds and ravaging crops and livestock feed along the way. In 1903 noted ornithologist W. L. Dawson said, “Without question the most deplorable event in the history of American ornithology was the introduction of the English sparrow.” Today they number about 150 million in North America.
Note: They’re not even sparrows—they’re from the weaverbird family.
Import: Cane toads
Background: The cane toad can grow up 9 to 10 inches long and weigh as much as 4 pounds. Its croak is said to sound like a dog’s bark. This bizarre species is native to Central America but was imported to Australia in 1935. Australian farmers wanted it to eat two types of beetle that were damaging their sugarcane crops.
Nature’s Revenge: Nobody seemed to notice that the cane toad lives on the ground—so they were only able to eat beetles that fell off the sugarcane. The experiment was a failure, then a disaster. The toads feasted on other native insect species—many to the point of extinction—and spread into neighboring habitats. They are large enough to eat any insect, as well as frogs and other toads, and have even been known to eat from dog and cat food bowls. And, to make matters worse, they’re poisonous. Whatever tries to eat them dies—even if they only eat the tadpoles. The situation continues to be dire: people who spot a cane toad are advised to contact toad hotlines and websites.
Chew on this: What’s a “winkle”? An edible sea snail.
Background: In the 16th and 17th centuries, hoards of people were leaving Europe on ships bound for the New World. Tyranny, poverty, horrendous filth, and epidemics drove boatload after boatload of settlers across the Atlantic seeking wide-open spaces, better resources, more freedom, and less disease.
Nature’s Revenge: The settlers found a pristine paradise—and quickly infested it with rats. Early ocean-crossing ships were famously rat infested, the vermin often numbering more than the humans onboard. The adaptable rodent made itself at home and spread all over the continent. According to a study by Cornell University, by 1999 there were approximately a billion rats in the United States—on farms alone, and rats do an estimated $19 billion in economic damage every year.
Import: Rabbits, opossums, and stoats
Background: New Zealand’s landscape had evolved for 60 to 80 million years with only four mammals—all bats. In this unique ecosystem, exceptionally unique flora and fauna, such as flightless birds, prospered. Then, in the early 1800s, Europeans arrived bringing sheep, pigs, and goats as livestock, and rabbits and opossums as game for sportsmen.
Nature’s Revenge: Rabbits multiply…like rabbits. By 1894 more than 17 million rabbit pelts were being exported annually. While that made money for some, the rabbits’ effect on the land, competing wildlife, and sheep farmers was devastating. The opossum did similar damage by eating massive amounts of native plant life in the exotic canopy.
Desperate farmers imported the stoat, a weasel-like creature that eats rabbits and opossums. That worked for a while, but birds, insects, and bats were easier for the stoats to catch. They quickly decimated bird populations, especially that of the kiwi. Thanks to the stoat, today several other species are either endangered or already extinct. New Zealand’s government spends millions every year trying to stop the continuing rampage. And what of the stoat’s intended targets, the rabbit and opossum? As of 2001, they were still the number one and number two pests in the country.
Rice-O-Roni: Italy produces the most rice of any country in Europe.