【高级听力】（文末附视频）Why Cities Can’t Get Rid of Rats
Why Cities Can't Get Rid of Rats
《文 末 附 视 频》
This may not be a word-for-word transcript.
Wormtail. Professor Ratigan. The R.O.U.S. Pop culture has given rats a bad rep. And honestly, it’s understandable why.
Take northeastern India’s rat flood. Twice a century, rats swarm when bamboo forests drop about 80 tons of seeds. After they devour the seeds, they devastate local agriculture. In the 1960s, the resulting famine was so bad, it led to a major political uprising.
So, it’s no wonder that the technical term for a group of rats is a “mischief”! And they’re not just a problem for farmers; these crafty rodents are the ultimate urbanites.
Meet your average city rats: Rattus rattus and Rattus norvegicus. These rats live pretty much wherever we do, especially in cities. Take New York City for example. We don’t know exactly how many rats call the Big Apple home. But a 2014 study gave a ballpark estimate of 2 million rats.
And that means in heavily-infested areas, you could have several rats per person! And in some ways, rats are actually better suited for living in cities than we are. After all, they can climb brick walls, they can “tightrope walk” over telephone cables, and their incisors grow 14 inches a year, which lets them gnaw into anything – including everywhere you don’t want them.
But their most powerful ability? Rats are clever – too clever. Scientists have shown that rats can learn to use tools. And when offered the choice between a chocolate and freeing a trapped friend, the rats choose to free their friend over chocolate!
When you translate those smarts into the real world, rats easily avoid traps. Trying to poison them won’t help much, either. They are extremely patient when it comes to new foods. They’ll taste just a tiny portion at first, wait to see if that food makes them sick and only if it doesn’t, will they consume the rest.
This is called “delayed learning” and it’s why rats are notoriously difficult to poison. Plus, they can develop resistance to many poisons over time. So, even if you outwit them, probably [it] still won’t work.
Another major issue is that rats reproduce so quickly. A single doe usually has 8-12 pups every 8 weeks! And those babies can have pups of their own after only 5 weeks!
So, as long as they have access to food, rat populations will rebound from just about any attack. The only attack they can’t handle is improved sanitation.
And cities are starting to figure that out. In 2017, for example, New York City launched a $32 million war plan against its rats – eliminate 70% of the rats in its 10 most-infested neighborhoods.
The plan is simple: cut off their food source.
You see, NYC produces around 33 million tons of trash a year – an endless buffet for the rats. The trash piles aren’t getting any smaller, so the city is at least making it harder for rats to reach the trash by replacing traditional trash compactors with a mailbox-style opening.
So, will NYC succeed by the end of 2018, as proposed?
Judging by the thousands of years where rats came out on top, it sounds a little too optimistic.
We’ve been talking a lot of trash about wild rats as problematic pests, but Pet Fancy rats are a completely different story. They don’t spread disease, they’re social, smart, and easily trainable. And get this, one amazing study found that rats giggle when you tickle them.
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