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Comment by ramblerman | Hacker News Reader

"Step one, therefore, would be to mount an intensive (and expensive) rat annihilation program. Residents would, no doubt, be happy to go rat-free, ..."

I despise rats. Yet I find it disconcerting that the author just brushes this off as a triviality. We are perfectly happy saving one species by wiping out another.

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Black rats are extremely common worldwide and are at no risk of extinction so nobody is 'wiping out' black rats. They're only talking about on Howe Island. The goal is not to avoid killing animals, it's to preserve biodiversity. Same reason people try to wipe out Kudzu, zebra mussels, snakeheads, rats, and other invasive species that displace endemic populations.

At one point there were more passenger pigeons on Earth than there were humans. Pigeons are widely considered by many folks to be little more than rats with wings, so it's unsurprising that few people cared as passenger pigeon populations were "wiped out", until ultimately the species became extinct.

I don't imagine that black rats will become extinct, but we should not pretend as though the prospect of "wiping out" local populations of any species is anything other than a morally ambiguous activity.

If the animal is an introduced species that has decimated native populations, I would think the morality quite straightforward.

Wiping out another - on that particular island, where they were non-native.

Invasive species cause havoc and removing them (whether by killing or by trapping[1]) is hard but useful work.

[1] See hedgehogs on some obscure Scots islands.

Duh, its evolution. You make it sound like a war theatre.

April 2003 - Attempts to begin a cull of hedgehogs on North Uist in the Western Isles have got under way.

(http://news.bbc.co.uk/1/hi/scotland/2920067.stm)

April 2005 - Animal rights activists are trying to rescue hedgehogs as an annual cull gets under way in the Outer Hebrides.

(http://news.bbc.co.uk/1/hi/scotland/4406675.stm)

October 2005 - Protest over annual hedgehog cull

(http://news.bbc.co.uk/1/hi/scotland/4390054.stm)

April 2007 - The board of Scottish Natural Heritage (SNH) has decided to suspend its cull of hedgehogs in the Western Isles.

(http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/63...)

February 2010 - Hebridean hedgehogs: a prickly issue The Uists cull has already cost more than £1m, but we should question the causal link between bird and hedgehog populations

(http://www.guardian.co.uk/commentisfree/2010/feb/25/hedgehog...)

February 2011 - £1.3m hedgehog cull to save islands' birds eggs 'fails'

(http://www.scotsman.com/news/163_1_3m_hedgehog_cull_to_save_...)

Also: Australia's efforts against the cane toad, invasive fish species all over the world introduced by humans for "sport", Florida's efforts against the Burmese python (which has become the dominant predator - even swallowing local adult alligators).

  > invasive fish species all over the world
  > introduced by humans for "sport"

Not just for "sport," IIRC there are some invasive species in the Mississippi River that got there when one of the floods engulfed some fish farms/hatcheries that had some exotic fish there to help maintain pests/algae/etc.

Also, Florida has a lot of iguanas (which are non-native), especially in the Everglades, you just don't hear much about it because the pythons are a larger issue.

Black rats are in no danger of extinction.

Even that, this means genocide for a species.

Nuclear weapons couldn't kill off even half of the rats on this planet.

Which is exactly why if we want to survive a nuclear war we need to start cross breeding with black rats and probably cockroaches.

Well that's an unpleasant mental image...

However, cockroaches actually aren't any better at surviving radiation than any other species, mythbusters tried it.

They can survive in harsher environments using less energy. Wasn't actually thinking about a rad-hard organism. Maybe throw in some flatworm, someone has to have a robust error-correcting code system built into their genetics.

Granted we would have to figure out a different neuro chemistry or physiology for having human level cognition on a much smaller energy budget.

They should import cats. Thats how they got rid from enormous rat population after Leningrad (current St.Petersburg, Russia) blockade during the WW2. That would be a natural way of annihilating rat population(passive killing).

So long as there's something there to eat cats. Introducing one invasive species to cure another can lead to unpredictable ordeals.

There are always big predators at top of the biological food-energy chain. They are few in numbers. Anyways, I believe populations of cats and rats will fluctuate. Increase in cats will cause decrease in rats and then subsequent decrease in cats. Like phase difference between sine and cosine wave graphs.

I believe introducing some small wild cat population would be a right thing to do, tho I would like to hear opinions of experts.

Edit: I don't think cats are invasive in the way rats are

> There are always big predators at top of the biological food-energy chain.

Not on islands. That's why islands have such unique animals found nowhere else.

Wouldn't the cats eat the insects?

Not exactly their niche. They might hunt for insects, but it won't be enough in terms of energy acquired. So probably they will reduce in population until rats' population will restore back.

And its good to keep rats busy. They won't wander as freely as they do now and hence eat less insects.

Those particular insects look big and juicy though. I know for sure my cat would love a snack like that.

A reasonable model if you assumed that cats exclusively ate rats - and wouldn't wreak havoc on any other native rodent populations (if they still exist).

Don't cats eat insects, too? I'm all in favor of getting rid of the rats, but I don't think cats are a solution.

Trouble with cats is they often destroy bird populations as well, not sure how much of a problem this is in Australia, but in New Zealand feral cats are up there with pests that need to wiped off any island that is to be rehabilitated.

The Stephens Island Wren is an excellent example of this http://en.wikipedia.org/wiki/Stephens_Island_Wren

Feral cats are a massive problem in rural Australia. They decimate small native mammals. The idea of introducing them to control rats and save native animals is insane - the cats would wipe out everything smaller than them.

Introducing a foreign species into an ecosystem has failed spectacularly so many times I cannot believe people still propose it.

Unfortunately cats don't eat only rats, they also like birds for instance. Look at the dodo extension mentioned in another thread, domestic animals played an important role there. Then the birds usually keep (nasty) insects population in control, etc and keeping a balance is tricky.

Snakes or other crawling rat predators would probably be a better idea, but then trying to convince the island people to share their space with snakes and weird looking insects at the same time would probably not go well :)

Snakes have bad impact on birds as well. Maybe not adults, but the eggs. I believe there is always a bigger fish in the ocean, everything is just a matter of equilibrium and its rules of self-control. Humans and rats probably are the only species that ignore those rules.

          'Look, I can explain,' he said.
          Lord Vetinari lifted an eyebrow with the care of one who, having found

a piece of caterpillar in his salad, raises the rest of the lettuce. 'Pray do,' he said, leaning back. 'We got a bit carried away,' said Moist. 'We were a bit too creative in our thinking. We encouraged mongooses to breed in the posting boxes to keep down the snakes...' Lord Vetinari said nothing. 'Er... which, admittedly, we introduced into the posting boxes to reduce the numbers of toads...' Lord Vetinari repeated himself. 'Er... which, it's true, staff put in the posting boxes to keep down the snails...' Lord Vetinari remained unvocal. 'Er... These, I must in fairness point out, got into the boxes of their own accord, in order to eat the glue on the stamps,' said Moist, aware that he was beginning to burble. 'Well, at least you were saved the trouble of having to introduce them yourselves,' said Lord Vetinari cheerfully. 'As you indicate, this may well have been a case where chilly logic should have been replaced by the common sense of, perhaps, the average chicken. But that is not the reason I asked you to come here today.'

--Terry Pratchett, _Making Money_

Cats come with their own problems. They were introduced on Kerguelen Island to eradicate introduced rats. The rats are left, and the cats eat endangered bird eggs.

http://www.btinternet.com/~sa_sa/kerguelen/kerguelen_species...

http://en.wikipedia.org/wiki/Kerguelen

This reminds me of an old Simpsons episode:

----

KENT Our top story, the population of parasitic tree lizards has exploded, and local citizens couldn't be happier! It seems the rapacious reptiles have developed a taste for the common pigeon, also known as the 'feathered rat', or the 'gutter bird'. For the first time, citizens need not fear harassment by flocks of chattering disease-bags.

Later, Bart receives an award from Mayor Quimby outside the town hall. Several lizards slink past.

QUIMBY For decimating our pigeon population, and making Springfield a less oppressive place to while away our worthless lives, I present you with this scented candle.

Skinner talks to Lisa.

SKINNER Well, I was wrong. The lizards are a godsend.

LISA But isn't that a bit short-sighted? What happens when we're overrun by lizards?

SKINNER No problem. We simply unleash wave after wave of Chinese needle snakes. They'll wipe out the lizards.

LISA But aren't the snakes even worse?

SKINNER Yes, but we're prepared for that. We've lined up a fabulous type of gorilla that thrives on snake meat.

LISA But then we're stuck with gorillas!

SKINNER No, that's the beautiful part. When wintertime rolls around, the gorillas simply freeze to death.

I doubt anybody in the world can anihilate rats.

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