Another creature many countries eagerly introduced to their homelands is the cane toad, a native of Venezuela and Guyana [source: Butler]. Like the European starlings, cane toads chow down on a lot of insects that can ruin sugarcane and other valuable crops. But these gigantic amphibians -- which can grow up to 15 inches (38.1 centimeters) long -- will eat almost any terrestrial animal, and fight with native amphibians for food and breeding grounds. Even worse, cane toads excrete a strong toxin from their skin that can sicken or kill domestic animals and wildlife, and even humans. People have died from eating the toads and their eggs, too [source: ISSG, WebEcoist].
Cane toads are especially problematic in the U.S. and Australia. In the latter country, some feel eradication is impossible because the toads' numbers are so great. One Queensland researcher is working on developing a strain of cane toad that can only give birth to males, ensuring the creatures' eventual demise, once the genetically engineered toads mate with regular ones [source: IMB - Institute for Molecular Bioscience]. However, only time will tell whether the cane toad or man is more resourceful -- and if we've finally learned our lesson about introducing non-native species into our homelands.
Author's Note: 5 Invasive Species That Might Conquer the World
When I was a kid, there was a popular sketch on "Saturday Night Live" about the killer bees that were coming to invade North America from the Southern Hemisphere. They reached America some 12 years after the sketch ran, and are entrenched in several southern states today, where they're causing agricultural turmoil -- although not mass murder, as some feared. Unfortunately, invasive species are a problem worldwide. I'm sure you all can quickly cite some of the problem plants, insects, birds or mammals in your own backyard. Just keep that in mind if you're ever tempted to buy an exotic pet, or plant a pretty -- but non-native -- plant in your backyard that's known to quickly spread. If we're all more watchful, we can help combat this problem.
- Alsup, Dave and Phil Gast. "16-foot python devours deer in Florida." CNN. Nov. 1, 2011. (March 26, 2012) http://www.fisheriesireland.ie/Press-releases/invasive-asian-clam-on-more-rivers.html
- Bamboo Wholesale. "Bamboo." (March 30, 2012) http://www.bamboowholesale.com.au/html/bamboo.html
- Brown, Carole Sevilla. "Most Hated Plants: Bamboo." Ecosystem Gardening. (March 26, 2012) http://www.ecosystemgardening.com/most-hated-plants-bamboo.html
- Butler, Tina. "Cane toads increasingly a problem in Australia." April 17, 2005. (March 30, 2012)http://news.mongabay.com/2005/0417b-tina_butler.html
- Columbia. "Introduced Species Summary Project: European Starling (Sturnus vulgaris)." (March 30, 2012) http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Sturnus_vulgaris.html
- EarthTrends. "Bioinvasions: Stemming the Tide of Exotic Species." July 2001. (March 30, 2012) http://earthtrends.wri.org/features/view_feature.php?theme=7&fid=18
- Environmental Graffiti. "The 5 Worst Invasive Species in the World." (March 26, 2012) http://www.environmentalgraffiti.com/offbeat-news/the-5-worst-invasive-species-in-the-world/463
- Fisheries Ireland. "Dangerous Invasive Clam found on the River Nore." July 20, 2010. (March 26, 2012) http://www.fisheriesireland.ie/Press-releases/invasive-asian-clam-on-more-rivers.html
- Great Michigan. "Invasive Species." (March 26, 2012) http://www.greatmichigan.org/additional-priorities/water/invasive-species
- Harrison, David. "Asian carp, other invasive species make a splash." Stateline. July 30, 2010. (March 26, 2012) http://www.stateline.org/live/details/story?contentId=502131
- Honolulu Zoo. "Cane Toad." (April 4, 2012) http://www.honoluluzoo.org/cane_toad.htm
- IMB - Institute for Molecular Bioscience. "Killing off the cane toad." (March 30, 2012) http://www.imb.uq.edu.au/index.html?page=48437
- ISSG. "100 of the World's Worst Invasive Alien Species." (March 26, 2012) http://www.issg.org/database/species/search.asp?st=100ss
- McDermott, Mat. "Invasive (and Dangerous) Species Alert: African Rock Pythons Invading South Florida." Treehugger. Sept. 14, 2009. (March 26, 2012) http://www.treehugger.com/natural-sciences/invasive-and-dangerous-species-alert-african-rock-pythons-invading-south-florida.html
- OMAFRA. "Why European Starlings Are A Perennial Problem: History And Biology Of European Starlings In North America." (March 30, 2012) http://www.omafra.gov.on.ca/english/crops/hort/news/tenderfr/tf0905a6.htm
- Pearce, Michael. "Unknowing fisherman may be spreading invasive Asian carp." Columbia Missourian. Aug. 27, 2010. (March 30, 2012) http://www.columbiamissourian.com/stories/2010/08/27/kansas-waterways-risk-invasive-carp-spread/
- Plants. "Phyllostachus aurea: Golden bamboo." (March 26, 2012) http://plants.ifas.ufl.edu/parks/bamboo.html
- The Wild Classroom. "Golden Bamboo." (March 26, 2012) http://www.thewildclassroom.com/biodiversity/problemplants/species/Bamboo.htm
- U.S. Forest Service. "Phyllostachys Aurea." (March 30, 2012) http://www.fs.fed.us/database/feis/plants/graminoid/phyaur/all.html
- Wallace, Rebecca. "International Standard Slows the Spread of Invasive Species." Forest Products Laboratory. (March 26, 2012) http://ahc.caf.wvu.edu/joomla/wpm/TechPapers/article6.pdf
- Walsh, Bryan. "Asian Carp in the Great Lakes? This Means War!" Time. Feb. 9, 2010. (March 30, 2012) http://www.time.com/time/health/article/0,8599,1962108,00.html
- Walsh, Bryan. "In a Globalized World, Are Invasive Species a Thing of the Past?" Time. June 14, 2011. (March 26, 2012) http://www.time.com/time/health/article/0,8599,2077582,00.html
- WebEcoist. "Incoming! The World's 10 Worst Invasive Species." (March 26, 2012) http://webecoist.momtastic.com/2009/12/15/incoming-the-worlds-10-worst-invasive-species/
- Zukerman, Wendy. "Australia's battle with the bunny." ABC Science. (March 30, 2012) http://www.abc.net.au/science/articles/2009/04/08/2538860.htm
HowStuffWorks looks at what the cleanest cities are doing to avoid a 'bad air day.'