
How rats became an inescapable part of city living - orcul
https://www.nationalgeographic.com/magazine/2019/04/rats-are-an-inescapable-part-of-city-life/
======
geowwy

        > From Seattle to Buenos Aires, urban rat populations are rising—as much as 15
        > to 20 percent in the past decade, according to one expert. Charismatic
        > animals like elephants, polar bears, and lions are all in decline, yet
        > inside our cities, we find it hard even with extraordinary efforts to keep
        > rat populations in check.
    

One big reason for that is the removal of free-roaming cats and dogs from
human habitats.

Free roaming cats and dogs have been a part of our society for as long as
we've been forming cities, we only recently decided to remove them. Of course
it's going to have the knock on effects we're now starting to see,

* vermin

* food waste

* wild animals venturing into cities

* etc.

~~~
hycaria
They went into trash nowadays. Also cats preying on birds and decimating them.
There's no ideal solution.

~~~
hobs
Because human cities didnt have gigantic midden piles before? There's no
change there.

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gnulinux
I grew up in Istanbul -- the cat city -- where free roaming cats are
everywhere and have never seen a mouse in my life. I thought "mice in city"
was a Medieval thing. Until I moved to Bay Area... And then I moved to
Boston... Turns out there are mice all over the cities in US.

EDIT: Also recently I learned I'm allergic to mice. This went undiagnosed for
22 years until I moved into Boston.

~~~
geebee
That's interesting, I've heard similar things about Rome (where I've never
been either).

My big worry about maintaining a large population of roaming cats is the
impact on the bird population. I'm interested in hearing directly from someone
who grew up in Istanbul - do you recall hearing or seeing birds often growing
up?

~~~
toyg
Didn’t grow up there but visited. Istanbul is on the sea, so there are plenty
of seagulls - aka “sea rats”, since they feast on trash. The few open / green
spaces I’ve seen had plenty of birds, mostly pigeon-like if i remember
correctly.

Been to Rome a few times too and that’s also pretty full of pigeons, afaik.
The feline colonies in Rome are the stuff of legend, several Italian writers
used them in stories. I bet they’ve been around since Roman times...

~~~
geebee
That makes a certain amount of sense. I'm not too surprised seagulls would be
ok in the presence of cats. They're large, fairly powerful birds. Crows also
seem more common in SF than they were in previous decades, and again, I'd
expect crows to be more resilient facing a predator like cats. They're large,
highly intelligent, pretty tough, and fight in groups.

Here's the thing - to a large extent, the birds you mentioned are urban birds,
by and large. Seagulls are very coastal, but as you said, they eat trash, so
the population will be very large in coastal urban areas. Crows also tend to
flourish in urban areas. Pidgeons are notoriously urban creature, and while
I've seen cats prey on them, they don't seem as vulnerable as smaller song
bird species.

I'm interested in whether these smaller songbird species are present in Rome
or Istanbul or other places that are cat-heavy, though there are of course
factors other than cats (some regions wouldn't have these species regardless
of the presence of cats).

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neonate
[https://outline.com/sPzj3G](https://outline.com/sPzj3G)

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SlowRobotAhead
“It is the tail,” says Laurinda Williams, who breeds rats on Long Island and
sells them as pets. “If it weren’t for the tail, everyone would have rats.”

Definitely true.

The other thing about rat size... man IDK. I was in Panang Malaysia and saw a
dead rat in a drain that blew my mind it was so large. It was no doubt in my
mind over 2lbs. It was nasiating to see, and I’ve seen rats in DC, NYC, Paris.
The articles claim of 1lb 13oz might be correct but it sure seems they must be
extremely light for their size.

~~~
stevekemp
Back when I was a student I kept a couple as pets, as they were much more
interesting than gerbils, mice, and hamsters. (That's about the size of pets
we had space for.)

I do recall a few people were weirded out by their tails, but I never really
understood it.

I'd be happy to keep rats again, they're intelligent enough to do interesting
things, and learn from their environment. They can also respond to simple
verbal commands - recognizing their names - and they're not at all prone to
biting children, which is a good thing!

~~~
InitialLastName
Seconded; I had a pair of rats until recently, and they made awesome pets:
affectionate, smart enough to play with, and with distinct personalities while
being pretty low maintenance (and willing to eat most of our food scraps). If
my partner hadn't developed a skin allergy to them (which made handling them
suck for her) we would for sure have acquired more when ours died.

Edit: in retrospect, I'm pretty sure that quote is from the breeder we used!
She's doing hamsters and rabbits now as well.

------
jpmattia
> _So the extermination industry uses anticoagulants, or blood thinners, which
> don’t affect rats for hours and don’t kill them for several days. The rats
> die slowly from internal bleeding. Corrigan hates to inflict such a death,
> but he fears outbreaks of disease. So he continues to lend his expertise to
> clients._

This is incredibly short-sighted thinking: Even if we ignore the horrible
death it inflicts, what happens to the anti-coagulants after the rat dies?

Here's one example at the top of the page:
[https://www.mountainlion.org/actionalerts/043014CAab2657/043...](https://www.mountainlion.org/actionalerts/043014CAab2657/043014CAab2657.asp)

It's not like these poisons hit a precise target and magically evaporate: They
remain in the environment, and then what goes around comes around.

------
garyscary
Guess we’re lucky not to have rats here in Alberta.

~~~
ceejayoz
I had no idea! Fascinating.

[https://nationalpost.com/news/canada/the-stirring-story-
of-h...](https://nationalpost.com/news/canada/the-stirring-story-of-how-
alberta-became-the-first-place-in-the-world-to-banish-the-rat)

------
calciphus
It's a little odd that the second paragraph of the article cites how rats "may
have transmitted plague" and then links to an article titled "Maybe Rats
Aren't to Blame for the Black Death".

Why?

~~~
imgabe
The "common knowledge" is that rats (or their fleas) transmitted the plague.
New research suggests this might not be the case.

~~~
joecool1029
Here is a link to that research: [http://sci-
hub.tw/https://doi.org/10.1073/pnas.1715640115](http://sci-
hub.tw/https://doi.org/10.1073/pnas.1715640115)

------
LoSboccacc
well, _something_ has to be there, right?

there's a lot of energy floating down there in the urban substrata, from
sewage and trash going upward, so a food chain naturally emerges as
opportunistic omnivores break the ground with predators following suite.

------
KangLi
I don't agree with the idea that rats size is exaggerated in NYC. I have seen
some at a building under construction at night that left me perplexed. A rat
on steroids I'd say, walking like a pitbull..

------
garyscary
I guess we’re lucky in Alberta to not have rats

------
mirimir
Little known fact: rats, mice and pigs are our closest relatives, beyond
primates. Which is why we test stuff on mice. And use pigs in developing
medical devices.

~~~
thaumasiotes
This can't actually be true, because rats and pigs are not closely related to
each other. Pigs are more closely related to whales than they are to rats,
which means that if (say) we were more closely related to pigs than to rats,
we would also be more closely related to whales than to rats.

In terms of taxonomy, primates are an order of mammals. It follows immediately
that humans are equally closely related to all non-primate mammals. (That's
not true either, as you can see by e.g. the designation of marsupials as an
"infraclass", a level between class and order, but it's the first
approximation to reality.)

~~~
klodolph
You say "that's not true either", but really, it was never true in the first
place. Traditional taxonomy is bad at determining how related species are. If
you want that, you look for evidences of common ancestors, or do DNA analysis.

I tried digging through Wikipedia articles on taxonomy, but it seems to be a
bit of a mess, with different articles in the hierarchy using different,
incompatible sources. It looks like rodents and primates are both members of
clade Euarchontoglires, with common ancestors 85-95 mya.

[https://en.wikipedia.org/wiki/Euarchontoglires](https://en.wikipedia.org/wiki/Euarchontoglires)

Clade Laurasiatheria is a sibling containing pigs, cats, whales, bats, and
many others. Common ancestor with primates is listed as ~80-100 mya (yes, this
number doesn't match the other one).

~~~
mirimir
I clearly recall reading that DNA-based phylogenetic analysis indicated that
primates and rodents have common ancestors that are more recent than common
ancestors with other mammals. So in that sense, rodents are more closely
related than, for example, dogs, cats, cattle, etc.

Pigs I may be wrong about. They're clearly more similar than dogs, cats and
cattle. In embryonic development, for sure, and I remember that from
dissecting a fetal pig. And there is the saying that embryology recapitulates
phylogeny. But a quick search didn't come up with any DNA-based phylogenetics.

As you say, "traditional taxonomy is bad at determining how related species
are". It's largely based on morphology, embryology and fossil evidence. But
that can be irffy, given the thin fossil record, and the common occurrence of
independent selection.

DNA-based classification is really the only way to get objective phylogenetic
trees. And as we get them, we learn that lots of classical taxonomy is just
wrong. And that's why reading about taxonomy online is so confusing. It's a
mix of old and new, with lots of more-or-less uninformed speculation.

~~~
thaumasiotes
> Pigs I may be wrong about. They're clearly more similar than dogs, cats and
> cattle. In embryonic development, for sure, and I remember that from
> dissecting a fetal pig. And there is the saying that embryology
> recapitulates phylogeny. But a quick search didn't come up with any DNA-
> based phylogenetics.

The saying exists, but it is not based in anything other than wishful
thinking. Ontogeny does not recapitulate phylogeny; that saying is the tongue
map of evolutionary analysis.

[https://en.wikipedia.org/wiki/Recapitulation_theory](https://en.wikipedia.org/wiki/Recapitulation_theory)

> the shortcomings of the theory had been recognized by the early 20th
> century, and it had been relegated to "biological mythology" by the mid-20th
> century. This did not prevent its propagation into the 21st century in a
> variety of biology textbooks.

If you believe the page on euarchontoglires, you can see that pigs cannot be
more closely related to humans than dogs, cats, and cattle, because all four
of those human-other pairings have exactly the same common ancestor, the
common ancestor of the euarchontoglires (the tree branch containing humans)
and the laurasiatheria (the branch containing pigs, cattle, cats, and dogs).
Any closer "similarity" between pigs and humans in specific is not driven by
their evolutionary relationship.

> DNA-based classification is really the only way to get objective
> phylogenetic trees. And as we get them, we learn that lots of classical
> taxonomy is just wrong.

DNA-based classification is not conceptually different from morphology-based
classification. They are both directly premised on the model of "descent with
modification". DNA-based classification is generally superior because there is
more information in the DNA than in the morphology. (Or at least, we recognize
more information in the DNA than we do in the morphology.) But morphology-
based classification did nearly 100% of the work of establishing modern
taxonomy, and overwhelmingly DNA-based analyses confirm the existing
morphology-based conclusions.

> traditional taxonomy is bad at determining how related species are

This is true in the sense of assigning a cardinal number to the relationship.
("Diverged 80mya.") It is false if your goal is only to assign an ordinal
number. ("Humans are closely related to baboons, distantly related to rabbits,
and remotely related to elephants.") The same objection applies to DNA-based
taxonomy; we get cardinal numbers by assuming a particular constant-rate
molecular clock, but the raw conclusions of DNA analysis are entirely ordinal.

> as we get them, we learn that lots of classical taxonomy is just wrong.

(quoting again to respond along another topic)

Notwithstanding the overall massive success of traditional taxonomy, there are
some obvious weak points. They tend to derive from philosophical beliefs of
the biologists rather than from failures of the morphology-comparing model.
Two major biases that I'm aware of are the historical belief that taxa at the
same level should include roughly the same number of extant species -- this
was featured in a "teach the controversy" sidebar in a college biology
textbook of my mother's -- and the stronger view that genera should contain
more than a single species. Since the groupings prompted by these beliefs were
not even _intended_ to "cleave reality at the joints", it's not so surprising
that they suffered under more objective analysis.

~~~
mirimir
OK, I've largely conceded re pigs.

But do you agree that there's a good case that rodents are more closely
related to primates than most other mammals are? Or do you believe that the
evidence is too weak?

I could do some serious literature research, I suppose. But I didn't really
set out to write a review.

~~~
thaumasiotes
I have nothing against the claim that rodents are closer to primates than
other mammals are. I don't think that goes a long way toward explaining the
use of mice in labs; it would be an equally strong argument for using gerbils,
rabbits, capybaras...

I think mice are used because they're small and easy to keep, and because by
now there's a lot of lab-mouse-specific infrastructure -- existing literature
about them, special strains of mice bred for use in the lab, and so on.
[https://en.wikipedia.org/wiki/Laboratory_mouse#History_as_a_...](https://en.wikipedia.org/wiki/Laboratory_mouse#History_as_a_biological_model)
suggests (in my eyes) that the use of mice is basically a coincidence.

The fact that they're at least as closely related to humans as other similarly
cheap, non-dangerous animals is a plus, but I don't think it was the reason
mice were used historically and I think it's only a minor contributor to the
continuing use of mice today.

When you're really hoping to transfer a finding over to humans, you use monkey
models, though I understand those are getting rarer under a combination of
cost and animal-rights-activism issues.

~~~
mirimir
From an historical perspective, I totally agree. Decades ago, when scientists
settled on the mouse model, I don't believe that there was much (if any) solid
evidence about evolutionary relatedness. As you say, mice were used because
they were the least-expensive mammalian option.

Even so, it's arguable that predictive success for the mouse model helped
drive its widespread adoption. Even so, just about all small mammals (e.g.,
rodents, shrews and moles) are more closely related to primates than large
mammals. So maybe it was inevitable.

> ... getting rarer ...

Funny story. I was a grad student in the late 70s. And there was an animal-
rights riot on campus. The primate lab was besieged. And some of us, whose
thesis research depended on our building's mouse colony, were totally freaked.

