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Speaker 1: Welcome to Brainstuff from house stuff Works dot Com, where

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Speaker 1: smart happens. I am your brain with today's question, which

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Speaker 1: invasive species is the worst one in the United States.

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Speaker 1: If you were to go back and look at the

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Speaker 1: United States a thousand years ago, the number and types

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Speaker 1: of animal implant species you would find would be quite

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Speaker 1: different than they are today. The change started with the

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Speaker 1: arrival of Europeans to the North American continent. Some of

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Speaker 1: the species they brought with themselves initially included farm animals

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Speaker 1: like horses, chickens, cattle, pigs, and even honey bees. None

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Speaker 1: of these animals existed in North America prior to the

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Speaker 1: arrival of the Europeans, and none of these species would

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Speaker 1: be considered to be particularly invasive either. That's because none

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Speaker 1: of these species spreads with any special rapidity, and none

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Speaker 1: of them, with the possible exception of feral pigs in

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Speaker 1: places like Texas, is particularly hard to control. In fact,

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Speaker 1: cows and chickens have some trouble surviving without human help.

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Speaker 1: One of the first invasive species that the Europeans brought

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Speaker 1: with them were brown rats, which arrived in the United

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Speaker 1: States sometime in the middle of the seventeen hundreds and

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Speaker 1: rats fit the definition of an invasive species perfectly. Rats

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Speaker 1: are a non native species that spreads rapidly, causes a

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Speaker 1: great deal of damage, and is extremely hard to control.

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Speaker 1: There could be as many as a hundred million rats

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Speaker 1: living in New York City alone. There really isn't any

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Speaker 1: way to do a definitive census, so no one knows

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Speaker 1: for sure. Amazingly, there are invasive species infesting the United

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Speaker 1: States today that are even more troublesome than brown rats.

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Speaker 1: Let's look at three of the most interesting to get

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Speaker 1: some sense of how invasive a species can be. One

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Speaker 1: of the most surprising is the Asian carp. You may

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Speaker 1: have never heard of this one if you don't live

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Speaker 1: along certain rivers in the Midwest, but if you do,

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Speaker 1: the spread of the Asian carp is spectacular. There are

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Speaker 1: millions of them, and they have a propensity towards leaping

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Speaker 1: out of the water as boats go by in numbers

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Speaker 1: that boggle the mind. You can find videos of Asian

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Speaker 1: carp on YouTube that shows stunning numbers of fish in

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Speaker 1: any given river. The problem is that the fish are big.

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Speaker 1: Twenty pounds or more is common. They eat a lot

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Speaker 1: and they reproduce rapidly, so they kill off all native fish.

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Speaker 1: One possibility is to harvest them for food, but people

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Speaker 1: in the United States do not tend to associate any

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Speaker 1: kind of carp with fine dining. Another invasive species is

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Speaker 1: the quagga muscle, a small fresh water shellfish about the

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Speaker 1: size of a quarter. To get an idea of the

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Speaker 1: problem quagga muscles create, take a look at the size

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Speaker 1: of Lake Michigan on a map of the United States.

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Speaker 1: Compare Lake Michigan size to the size of a state

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Speaker 1: like Massachusetts or Connecticut. Now imagine the floor of Lake Michigan,

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Speaker 1: the whole thing covered in a dense layer of quagga muscles.

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Speaker 1: The muscles filter all of the beneficial food algae out

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Speaker 1: of the water excreted as feces, and in doing so,

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Speaker 1: promote the growth of other forms of algae that can

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Speaker 1: create a stinking mess on shore. At the same time,

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Speaker 1: with the beneficial algae gone, the number of fish in

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Speaker 1: the lake has plummeted. Muscles like the quagga have a

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Speaker 1: tendency to clog pipes for things like municipal water systems

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Speaker 1: as well. It's also possible for an invasive species to

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Speaker 1: be a plant and kud Zoo is a great example.

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Speaker 1: If you live in the southeastern United States, you cannot

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Speaker 1: miss kudzoo because it is a vine that is very

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Speaker 1: hard to stop. In the summer, kudzoo vines grow as

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Speaker 1: much as a foot per day. You can almost see

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Speaker 1: kudzoo growing if you sit and watch it. Because it

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Speaker 1: throws so fast and has very dense foliage, kut Zoo

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Speaker 1: can grow right over trees and smother them. Kud Zoo

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Speaker 1: will also grow over things like houses, power lines, and

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Speaker 1: so on, and can cause a great deal of damage

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Speaker 1: when it does that. It has very deep, bulbous roots

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Speaker 1: that make kud zoo difficult to eliminate from a piece

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Speaker 1: of land. There are many other invasive species in the

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Speaker 1: United States, including things like Starling's fire ants and even

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Speaker 1: pythons that are proliferating in the Everglades. Efforts to control

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Speaker 1: them have so far proven to be fairly futile. In

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Speaker 1: each case, we hope that science can figure out some

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Speaker 1: way to control their spread, or that the marketplace can

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Speaker 1: create some kind of widespread demand for them so they

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Speaker 1: come under predatory pressure from human beings. For more illness

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Speaker 1: and thousands of other topics does that house stuff works

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Speaker 1: dot Com and don't forget to check out the brain

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Speaker 1: Stuff blog on the house stuff works dot com home page.

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