What is the worst invasive public species?

From kudzu to cane toads, invasive species are changing the world. But which of these transplants is the worst for the local landscape? Tune in as Marshall Brain tackles invasive species across the world -- and ultimately concludes which one is the worst.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:00):
Welcome to Brainstuff from house stuff Works dot Com, where
smart happens. I am your brain with today's question, which
invasive species is the worst one in the United States.

(00:20):
If you were to go back and look at the
United States a thousand years ago, the number and types
of animal implant species you would find would be quite
different than they are today. The change started with the
arrival of Europeans to the North American continent. Some of
the species they brought with themselves initially included farm animals

(00:41):
like horses, chickens, cattle, pigs, and even honey bees. None
of these animals existed in North America prior to the
arrival of the Europeans, and none of these species would
be considered to be particularly invasive either. That's because none
of these species spreads with any special rapidity, and none
of them, with the possible exception of feral pigs in

(01:01):
places like Texas, is particularly hard to control. In fact,
cows and chickens have some trouble surviving without human help.
One of the first invasive species that the Europeans brought
with them were brown rats, which arrived in the United
States sometime in the middle of the seventeen hundreds and
rats fit the definition of an invasive species perfectly. Rats

(01:25):
are a non native species that spreads rapidly, causes a
great deal of damage, and is extremely hard to control.
There could be as many as a hundred million rats
living in New York City alone. There really isn't any
way to do a definitive census, so no one knows
for sure. Amazingly, there are invasive species infesting the United

(01:46):
States today that are even more troublesome than brown rats.
Let's look at three of the most interesting to get
some sense of how invasive a species can be. One
of the most surprising is the Asian carp. You may
have never heard of this one if you don't live
along certain rivers in the Midwest, but if you do,
the spread of the Asian carp is spectacular. There are

(02:09):
millions of them, and they have a propensity towards leaping
out of the water as boats go by in numbers
that boggle the mind. You can find videos of Asian
carp on YouTube that shows stunning numbers of fish in
any given river. The problem is that the fish are big.
Twenty pounds or more is common. They eat a lot

(02:30):
and they reproduce rapidly, so they kill off all native fish.
One possibility is to harvest them for food, but people
in the United States do not tend to associate any
kind of carp with fine dining. Another invasive species is
the quagga muscle, a small fresh water shellfish about the
size of a quarter. To get an idea of the

(02:52):
problem quagga muscles create, take a look at the size
of Lake Michigan on a map of the United States.
Compare Lake Michigan size to the size of a state
like Massachusetts or Connecticut. Now imagine the floor of Lake Michigan,
the whole thing covered in a dense layer of quagga muscles.

(03:13):
The muscles filter all of the beneficial food algae out
of the water excreted as feces, and in doing so,
promote the growth of other forms of algae that can
create a stinking mess on shore. At the same time,
with the beneficial algae gone, the number of fish in
the lake has plummeted. Muscles like the quagga have a
tendency to clog pipes for things like municipal water systems

(03:36):
as well. It's also possible for an invasive species to
be a plant and kud Zoo is a great example.
If you live in the southeastern United States, you cannot
miss kudzoo because it is a vine that is very
hard to stop. In the summer, kudzoo vines grow as
much as a foot per day. You can almost see

(03:56):
kudzoo growing if you sit and watch it. Because it
throws so fast and has very dense foliage, kut Zoo
can grow right over trees and smother them. Kud Zoo
will also grow over things like houses, power lines, and
so on, and can cause a great deal of damage
when it does that. It has very deep, bulbous roots

(04:17):
that make kud zoo difficult to eliminate from a piece
of land. There are many other invasive species in the
United States, including things like Starling's fire ants and even
pythons that are proliferating in the Everglades. Efforts to control
them have so far proven to be fairly futile. In
each case, we hope that science can figure out some

(04:38):
way to control their spread, or that the marketplace can
create some kind of widespread demand for them so they
come under predatory pressure from human beings. For more illness
and thousands of other topics does that house stuff works
dot Com and don't forget to check out the brain
Stuff blog on the house stuff works dot com home page.

(04:58):
You can also follow brains up on Facebook or Twitter
at brain stuff hs w M. The house Stuff Works
iPhone app has arrived. Download it today on iTunes, m