50 Interesting Facts about Invasive Species

The North American Gray Squirrel is considered an invasive species in Britain as they carry squirrel pox, which is deadly to the Red Squirrels native to Britain. The Gray Squirrel also eats seven times as much food as the Red Squirrels, crowding out any who survive the squirrel pox.

2. In 2013, USA bombed the island of Guam with 2,000 dead mice stuffed with painkillers to kill the Brown Tree Snake which is an invasive species on the island. The snake got there by accident in the 1950s on a shipping vessel.

3. From 1930s through 1950s, Soil Conservation Service in the USA promoted planting of kudzu plants in the south to fight soil erosion. The vine of kudzu plants can spread over one foot a day and spread through runners, rhizomes, and by vines that root at the nodes. This plant is now overtaking entire areas, out-competing all other plants including trees.

4. In 1960, Chicago Mayor Richard J. Daley gave Prince Akihito of Japan bluegill fish. He in turn gifted it to fishery research agencies in Japan. They escaped captivity and wreaked havoc with native species, provoking a rare public apology from the prince.

5. A bill was proposed in 1910 to release hippos into the Louisiana bayous, both as a way to clear out invasive water hyacinth and solve a critical shortage of meat. It was backed by Former President Roosevelt and The New York Times, which praised hippo meat as tasting like "lake cow bacon." The bill failed to pass by just 1 vote.

European Starlings are an incredibly invasive species that were introduced to the US by Eugene Schieffelin. He was convinced that the USA needed every bird in Shakespeare's works, so he released around 100 starlings in New York City in 1890. They are now one of the most abundant birds in North America with populations exceeding 200 million.

7. The common Tumbleweed which has been used to symbolize the American frontier in Hollywood movies is an invasive plant species native to Russia. They arrived through a contaminated flax shipment from Russia. The only two states that have not been infested by it are Alaska and Florida and they reportedly very tasty as a boiled vegetable or in salads.

8. Fire Ants are an invasive species to the US. The FDA estimates that $5 Billion is spent annually on medical treatment, damage, and control in areas infested with the ‘Red Imported Fire Ant.’

9. The lionfish is a prolific invasive species in the Atlantic Ocean and sharks typically don't recognize them as prey. It is decimating native ecosystems and is thought to be responsible for a drop in the biomass of native reef fish species by an average of 65 percent. To control its population, conservationists have attempted to train reef sharks to prey on them and even chefs and diners are campaigning to eat them.

10. Hydrilla was introduced to America in the 1950s by someone who discarded a used aquarium containing the plant in waters near Tampa Bay, Florida. It is now one of the most invasive marine plant species in the Western hemisphere and notoriously difficult to manage, much less eradicate.

Bradford Pear trees are considered a highly invasive species. It was once thought they would be sterile as a hybrid. They're incredibly weak and are often damaged in storms, so their life span is usually 15-20 years. They are also known as the "sem*n tree" due to its distinctive smell, which has been descried as a cross between rotting fish and sem*n.

12. The walking catfish can breathe air and use its pectoral fins to "walk" and move to different aquatic environments. Native to Southeast Asia, it became an invasive species in Florida during the 1960s and has been sighted in California, Connecticut, Georgia, and England.

13. Biologist Warwick E. Kerr crossbred European and African honeybees to make a hybrid that would produce more honey in tropical conditions. He accidentally created the killer bee, a deadly variant that has since become one of the most successful biologically invasive species of all time.

14. Japan is infested with invasive North American Raccoons, due to the popularity of the 1977 Cartoon series "Rascal the Raccoon." Thousands of Japanese adopted Raccoons, only to let them into the wild when they proved to be poor pets.

15. Marbled Crayfish is the only type of crayfish that can clone itself. All specimens of marble crayfish are female. Since no known wild population of it existed before it was discovered in pet trade by aquarium hobbyists, it is speculated that they are the result of accidental hybridization. It is now an invasive species in many counties.

The Asian Hornet accidentally came to France with some pottery from China in 2004. It has since become an invasive species, is now populated all over France, and is currently sweeping through the rest of Europe as we speak.

17. The Hawaiian Islands do not have any squirrels, but they do have Mongooses, which were released in the 1800s to help control the rat population and are now considered an invasive species.

18. Japanese Knotweed is listed by the World Conservation Union as one of the world's worst invasive species. It can damage buildings, roads, and architectural sites, and it's considered an epidemic in the UK, where it has spread nationwide. It is illegal to have it on your property in Australia.

19. The common House Sparrow was first introduced in the US in the 1850s when 25 mating pairs were released in Brooklyn. They then became an invasive species, but are currently declining in numbers across the country for unknown reasons.

20. Asian Carp is one of the most problematic invasive species and was introduced as an ecologically friendly way of controlling algae and invasive plant species. Scientists studying them have to wear protective head gear as they routinely jump out of the water and can cause severe head injuries. They are such a nuisance that an extreme fishing sport named Skarping has evolved around waters infested with them where competitors waterski armed with tridents, swords, and even basketball hoops.

The brown marmorated stink bug is an invasive species in the USA. It was introduced from Asian countries in the late 1990s. Its odor can also be compared to the smell of coriander (cilantro).

22. Crazy Ants are an invasive ant species that have invaded the USA, have disrupted food chains by eating everything, are immune to fire ant venom, and are the trickiest for exterminators. They can be so great in number in a colony that they blanket the ground. They also target and short out electronics like air conditioners.

23. There is an invasive species of flatworm in Ireland called the Australian Flatworm which feeds exclusively on earthworms. This has proven catastrophic for soil fertility and has led to serious plantation problems and has cost the Irish government millions.

24. Cannabis is invasive in North America and is referred to as 'feral cannabis,' 'wild marijuana,' and 'ditch weed' when it grows in the wild. Its seeds can lie dormant for 7-10 years and the wild plant can damage farm equipment. Feral cannabis is cultivated in North Korea.

25. Giant hogweed is a towering, invasive plant, whose sap is extremely phototoxic. If you touch the sap and are then exposed to UV rays from sun, it will produce severe caustic burns. These chemicals are also known to bond with your DNA and kill it.