- [Narrator] Wormtail. Professor Ratigan. The R.O.U.S'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 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 it's not just that
they're 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 two 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're 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 still won't work. Another major issue is that
rats reproduce so quickly. A single doe usually has eight
to 12 pups every eight weeks. And those babies can
have pups of their own after only five 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, New York City launched a $32 million war plan against its rats. Eliminate 70% of the rats in 10 of its most infested neighborhoods. The plan is simple, cut
off the rats' food source. You see, New York City produces around 33 million tons of trash a year, an endless buffet for the rats. And the trash piles aren't
getting any smaller. So the city is at least making it harder for the rats to
reach the trash by replacing traditional trash compactors
with a mailbox-style opening. So, will New York City 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.
