Humans like to meddle with nature. It’s what we do. It’s our thing, y’know? If we weren’t smashing stones together and wiping out other species, we just wouldn’t be human. The paleontological record clearly shows that since humans arrived on the scene large animals – from woolly mammoths to moas to Neanderthals – have been dropping like flies.
Since the renaissance and the advent of ships and intercontinental voyages, we’ve been mucking about with nature in a more subtle (and often more devastating) fashion: moving plants, animals and diseases from where they do belong to where they don’t belong.
Classic examples: The introduction of smallpox to the Americas decimated the native Indian populations, who had not built up a resistance to the virus like Europeans. Rats and cats have almost completely wiped out many species of flightless birds in New Zealand (whose only native mammals are bats). Zebra mussels – presumably transported from the lakes of southeastern Russia to the Great Lakes of North America in ballast water – have crowded out many native species (and become a giant headache for those forced to clean them out of the pipes they frequently clog).
Last century, many of the worst alien species around the world were deliberately introduced into new habitats by well-meaning and misguided people. In the 1930s farmers in the drought-riddled southern US were encouraged to plant the kudzu, a climbing vine native to Japan that thrives in dry soil, in order to control erosion. Unfortunately, without it’s natural predators and diseases and so forth, the plant exploded beyond control. Today it’s known as “the plant that ate the south” – if you drive through the southern US (which I spent much of my childhood doing) you can see it everywhere, cascading over trees and forests for miles and miles.
Perhaps the most famous invasive alien is one of the funniest: the cane toad. The toad was introduced to Australia (from it’s native Central America) to control the pesky cane beetles that were eating the sugar cane crops. The large, foul-tempered toad, upon arrival in Australia, did not in fact eat the beetles – instead, they ate just about everything else.
To make matters worse, the toad’s skin is extremely poisonous – so unsuspecting gators and other predators that tried to eat the animal croaked (badum ba CHING!). AND, if that wasn’t bad enough, the toads are one of those amphibians that employ “explosive breeding” techniques. Instead of having a few tadpoles at a time – like, say, a poison dart frog – they have mass orgies that result in huge sticky masses of eggs and sperm that spawn huge numbers of nasty, black tadpoles.
The toad is a huge problem in Australia, and it doesn’t seem like they will ever be able to eradicate it. In fact, it’s spreading – volunteers the other day captured a massive specimen in Darwin, weighing more than 2 lbs, the largest ever caught in the Northern Territory.
Sobering thoughts. Be careful before you go messing with nature.
The upside to the cane toad tragedy is that there is a hilarious documentary about the creatures from 1988 titled simply Cane Toads. It covers the whole spectrum of cane toad culture in Australia, from the motorists who enjoy running over the toads to hear the big booming explosion noise they make, to druggies who smoke the poison, to children who keep the animals as pets and dress them up in pink doll dresses. I highly recommend that you see this film.
I looked on youtube for a clip of the girls with their doll-toads, but alas, none could be found. I did find this photo though: