Kill all the kittens

Eric Crampton

Gareth Morgan wants to eradicate cats from New Zealand. His campaign website does a good job in describing the various evils cats perpetrate upon our ridiculously pacifistic native wildlife. But it's missing the first thing I'd have expected in a policy campaign coming from an economist: a cost-benefit analysis.

First, how much consumer surplus is generated by cats? It has to be pretty big.

The New Zealand Companion Animal Council claims* that the 48% of NZ households owning at least one cat spend on average $838 per year on their cats. 1.419 million cats at $466 per cat is about $660 million spent on caring for cats. I don't know what the price elasticity of demand for cat ownership is, but aggregate surplus seems awfully likely to be big.

Second, how elastic are wildlife numbers to cats' presence? Cats kill a lot of things; they're awfully murderous. But if they weren't there, would native wildlife rebound, or would the population of other predators expand with the reduction in competition?

Thirdly, how much value do we really place on native wildlife? Sure, we get some existence value from the birds and lizards that cats eat, and it's nice seeing them and hearing them. But is it enough to trump the consumer surplus that people get from cat ownership? I don't know and neither does Gareth. But I'm not the one wanting to kill all the kittens.**

Shouldn't we have to run a cost-benefit analysis before considering kitty genocide?

A common sense solution
Gareth does recommend a few potentially useful things, like belling cats. I doubt that the cats who do the most damage would be the ones that are belled, but the proposal at least doesn't seem likely to do much harm. Another option: make your next cat a Persian. Our last one was so ridiculously over-bred*** that she could barely eat kibble, much less do any harm to, well, anything other than furniture, carpets, clothing, and my dignity.

Optimal cats
I'm not sure that you can make a case for the phased abolition of cats from New Zealand within a utilitarian framework, even one counting animals' utility directly, without arguing that you also have to abolish any carnivore elsewhere in the world whose prey**** is not at the Malthusean fringe.

It's conceptually easy to add animals' utility to utilitarianism; read Peter Singer. Animals utility will be weighted by their self-awareness and capacity for pleasure and pain, but it counts positively and directly in the social welfare function. This interview of Peter Singer by Tyler Cowen is superb, though it doesn't hit this topic directly.

If the marginal increase in terror imposed by cats on their prey*, accounting for that cats may have greater self-awareness and greater capacity for pain and pleasure than do prey species, outweighs the cat's enjoyment of its own life (including all the murder) and the cat owner's enjoyment of the cat, then a Singer framework would support getting rid of cats. If pet owners get particular disutility from the forced euthanasia of their pets relative to not being allowed to get a new one, then it could be consistent with Gareth Morgan's proposed mandatory neutering and non-replacement.

But it's also consistent with other required policies. The proposal above is only optimal where prey animals would otherwise have had happier lives and deaths: trading starvation at the Malthusean fringe for death by cat might not be all that bad. But consider rabbits and mice in Britain that feed on crops and are not at the Malthusean fringe. Foxes that eat them then do harms little different from the harms imposed by cats here. And what of the terrors keas impose on helpless sheep?

Aha, you might say: rabbits and mice are not endangered, while some New Zealand native bats and birds could be. This matters in a Singer setup to the extent that people value endangered species more at the margin than they value rabbits and mice, and to the extent that any extinction may have flow-on effects elsewhere, but we also have to weigh it against cat owners' enjoyment. And given the likely rather large consumer surplus provided by cats, well, I'm not sure the case is obvious.

If you step outside of the utilitarian framework, it's perhaps easier to derive a "abolish cats but leave foxes alone" conclusion. Harry Clarke puts up a biodiversity standard, arguing that biodiversity should be sought for its own sake and regardless of whether people gain enjoyment from biodiversity. But if there's a continuum of policies that could be undertaken to encourage biodiversity, and if some are very costly, we have to draw a line somewhere about trading off biodiversity against other goods. And that puts us back into a utilitarian cost-benefit assessment even if we're adding in biodiversity as a non-preference-related constraint.

I'm not against this kind of messy pluralism; it's close enough to my own messy pluralism, where I invoke liberty side-constraints on utilitarianism rather than biodiversity side-constraints. But isn't it worth weighing up the shadow prices of the incremental gains? You have to put ridiculously high weight on the side constraint to reckon we shouldn't even consider cat owners' forgone enjoyment. And I'm not sure that there isn't a fundamental underlying anthropocentrism even to biodiversity standards where at least some of it seems to require choice among equilibria, and a lot of weight put on particular ex ante status quos.

If many of New Zealand's species arrived here long after separation from Gondwanaland, and then evolved here, how far back should we go in turning back the clock? Sure, there was a stable equilibrium here before the arrival of Maori. But there would have been a stable equilibrium before the arrival of bats and buttercups too. And if the pre-human equilibrium was the 'best' one because it included some best stable set of creatures that didn't exist elsewhere, and we should invest resources in maintaining that set of creatures at the expense of other ones, why shouldn't we also invest resources in developing new creatures that do not exist elsewhere? There are lots of ways of increasing biodiversity.

Dr Eric Crampton is Senior Lecturer in Economics at the University of Canterbury. He blogs at Offsetting Behaviour.

* I have no clue how reliable their survey is.

** Ok, he isn't really saying we should kill them all, just that we should phase them out over time. But, still, I'm pretty sure that every time you drink a Coke, Gareth Morgan kills a kitten.

*** We got her from the Cat Protection League's cattery. Long story there. After we moved to New Zealand, Susan insisted we get a cat. I asked that it please please please not be another long-haired one. She sent me to the bank machine to get cash to pay the Cattery after we'd been looking at a nice short-haired one. When I got back, she'd signed all the paperwork for a defective Persian with a substantial underbite. The cat was lost eight years later consequent to the earthquakes.

****  Every animal dies of something, eventually. If the cat kills an animal that otherwise would have died a painful death of Malthusean starvation, it has done no harm and may have done good. If the cat kills an animal that otherwise would have had a long and happy life because the environment is well below carrying capacity because there are too many predators, then it has done harm. If it kills an animal that otherwise would have soon been eaten by a weasel, rat, stoat or possum, then it's done no harm. See discussion of vegetarianism and eating fish in the Cowen-Singer discussion above-linked.

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the biggest problem on this planet and nation is rotten ol human beings not cats .


It's all relative sunshine. I think many species are doing rather well under human dominance.


Gareth Morgan has had a personality issue since his son made him a fortune and he then managed to sell his Kiwisaver business to kiwibank for a ridiculously high price.

His ego is out of control - he thinks he runs NZ and has all the answers for every issue out there. His intentions are admirable but his arroagance and delivery of his well intentioned message is second rate and not well received by the general public.

He needs a PR firm to advise him how to deliver his message without offending the majority of the public. His " don't care a stuff" attitude is his perogative but only results in the public giving him the finger and all his good intentions are worthless.

Maybe think before you speak Gareth - your Phoenix captain and players think you should and so do we.


If you can't attack the argument attack the man. Ad hominem is so passe Mr Doctor.

Why aren't all cats spayed and belled? Why should they be allowed to wander and kill where ever they want to go? Why should I as a property owner have to put up with the presence of other peoples cats? Can I destroy those who invade my property?
I think if we were to spay and neuter and bell domestic cats, then actively cull feral ones, most of the damage done would be minimised. People would be able to keep their beloved moggies all the while feeling happy that they are environmentally responsible. But good on Gareth for starting the conversation.


That is disgusting Cats and Kittens have as much rite to life as us humans. Humans cause more distruyction than cats. LEAVE THEM ALONE GARETH


Mr Morgan is a number and concrete thinker; that is why he is a successful economist.
It may have been mentioned elsewhere: There are other aspects of cat usefulness.

Children learn to care and nurture
Disabled children and adults feel loved unconditionally
People with intellectual disabilities relate to cats' affection
For some people (especially those living alone) their cat (or dog) is their best friend - unconditional love, no criticism, always there regardless of one's mood, and they do not speak, they do not ask questions; their eyes speak for them.
People with terminal illness often need their best cat or dog friend to be with them to provide comfort.
Love of cats is not new. What about Egypt and Abysinia?
Empathy, as we all know is being able to see the world through other people's eyes.


Exactly, Gareth should stay in China where they eat cats and dogs and everything that moves, where life has no value unless you have money. I' sure he is enjoying all those desperate sycophants over there licking his ass but I wonder if he realises those same people would kill him as "quick as look at him" if there was a war on. (Look into their eyes Gareth and say "no they are caring altruistic people" ...ha they don’t even blink if a 5 year old is run over by a truck in front of them.)

I use to think Gareth was above that delusional elitism because he was from humble beginnings but now he has lost all credibility - what a waste.

History will look back on your small minded ideology Gareth and laugh.


He is spot on. Cats should be gone, and better methods developed to remove other predators too


Man, of course, being the greatest predator of all...


Other predators like Gareth Morgan, you mean.


A couple of cats have owned me over the last 30 years. They have on occasion, not often brought home
birds. Sparrows, Thrushes, Blackbirds and once a Mynah.
I cannot remember them ever catching a native bird.
I think that this shows the real problem our native species have, competition with the introduced species that Gareth's ancestors brought with them.
If there were no competing introduced birds imagine how the native population would expand.
Unfortunately that cat is out of the bag.
I note that the bird in the mouth of the cat on Gareth's web page is not a native, looks like the Canary the cat got. Not endangered in the least.


I have pedigree cats that don't jump fences or climb trees, stay in the yard, come when called and don't eat wild life. They prefer the house and follow me around like dogs.
Here's a better idea - selective breeding of traits.

I find it really sexist the way in which traditionally female pets '-cats' are targeted in a way that dogs aren't .
Dogs have a high impact on native animal habitats and movement. We have hunting dogs - cats could never do the job of a hunting dog nor come close. Cats can't dig, bite or carry and drag as well as a dog.

However anyone that suggested the eradication of dogs would be considered a loon.

Casual sexism - when sexism is taken to the extreme of targeting gender favored pets and no one thinks it is abnormal or sick because no one questions popular but erroneous beliefs like cats having a higher impact on native animals than dogs do.

The birds where I live attack and tease the cats. The cats run from the possums and even a hissing tree frog confounds them. Lizards are about the only occasional prey and lizards. Can. Burrow. Better. Under. Leaflitter.

Retractable claws aren't made for hunting with and a cats jaws aren't exactly top level predator.

Beware of the cat signs are ridiculous and hanging a bell on your dog won't help anything a dog hunts escape.

House cats in the wild are more prey than predator. Ask any dog.

Darned loony cat haters.

Native animals are becoming extinct - I see a lot of them on roads with tyre skid marks or a little bit charcoaled. Feel free to ring up your local wildlife care group and ask them how many of their sick and injured wildlife in their care are 'cat rescues'.


Mr Morgan's anti-cat crusade displays the dogmatism, one-sidedness, neglect of history, lack of social understanding and fetishism of simplistic conceptual models so typical of bourgeois economists.

It's completely misguided, not just because it appraises unrealistically the intimate human/cat social interaction, but also because there is strong evidence that, so long as an ecosystem also includes rats, mice or rabbits, cats are a net benefit to bird populations despite killing some birds themselves.

That's because cats eat rodents and rodents are more effective bird predators/competitors than cats. Cats much prefer rodent prey to birds and each cat kills many rabbits, rats and mice.

The disaster that ensued on Macquarie Island when cats were eradicated in 2000 to protect birds is a good case in point. Without the cats, rat and rabbit populations exploded, leading to an ecological catastrophe in just a few years. In the same way, the Amsterdam Island attempted cat eradication led to a disastrous population explosion of rats and mice.

Only if rats were eradicated from the NZ mainland at the same time would it make ecological sense to get rid of cats, and then only if all the weasels, ferrets, stoats, mice and rabbits were killed off simultaneously as well. But that prospect is even more of a pipe-dream than Mr Morgan's risible cat eradication fantasy.


Leaving aside the question of whether or not it's wise to dignify Gareth Morgan with the title of economist - most would say he gives economists a bad name - I'd be interested to know how his views on cats "display" anything at all to do with economics. If anything they seem far more reminiscent of law, i.e., if X is bad, pass a law against it. As Eric Crampton points out, an economist would weigh up the costs and benefits of doing so.


Bunter, you've made an elementary logical error.

Pointing out that the scientific failings displayed by Mr Morgan's anti-cat thing are the same ones he shares with many other bourgeois economists in their professional capacities does NOT mean claiming that Mr Morgan's anti-cat thing displays bourgeois economics.

If X displays Y and Z displays Y, that doesn't imply that X displays Z.

Your point about legalism is well made though.


So you're saying that economics is right, but economists are wrong?




Garweth should come up with an innovative way of getting wid of stoats, but I guess that would be far too useful and far too little sensational.


Absolutely stoats are far more of a problem.

While on the subject of wild (pets) doing great harm, where is Gareth when another child or adult is mauled and scarred for life by some mongrel or pedigree dog. Far more good to society would be achieved by coming up with a solution to this issue and leave cats alone.

If GM had spent more time looking after the member's interests in his Kiwisaver fund they and NZ would be better off financially. The GM Kiwisaver scheme is a very poor performer and the only one who got rich was GM. He is no benevolent benifactor when it comes to making a buck or million.


Gareth absurd rants actually may point to some lack of real pussy in his life. Perhaps he needs a bird of the two legged variety to lighten him up a little?? For an intelligent guy like Morgan to be unable to recognise that he is destroying is own brand, by failing to engage brain before opening mouth, should be worrisome for him.


Well, you've surely lowered the tone there, Paul. Plus, I thought birds were generally two-legged anyway. Tell us where you've been travelling. Please

But I do agree entirely with your last sentence.


Sounds like Gareth Morgan should be spayed and made to wear a bell.


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