When Do 60 Rats = 1 Cellphone?

Our recent podcast “The Cobra Effect” explored the unintended consequences of bounty programs. The episode was inspired by a visit to South Africa not long ago, where I was told about a rat problem in the Johannesburg township of Alexandra. For whatever reason, that story didn’t make the episode. But now the Guardian comes to the rescue, reporting on Alex’s efforts to fight off the rats by offering a cellphone for every 60 rats caught:

[C]ity officials have distributed cages and the mobile phone company 8ta has sponsored the volunteer ratcatchers.

Resident Joseph Mothapo says he has won two phones and plans to get one for each member of his family. “It’s easy,” he told South Africa’s Mail & Guardian newspaper, wielding a large cage containing rats. “You put your leftover food inside and the rats climb in, getting caught as the trap door closes.”

But there were signs that the P.R. stunt could backfire, as animals rights activists criticised the initiative on social networks.

Will this lead to rat farming or other shenanigans? The Guardian reports that owls have also been distributed to help hunt down the rats.

(HT: Joe Sternberg)


Reminds me of the cobra effect from the botched campaign to eliminate cobras in Dehli. Countdown to people breeding rats on purpose for the reward.


A local egg farm had a liquid manure pit which had millions, perhaps hundreds of millions, of houseflies. They sprayed insecticide, they trapped, they even used giant fans to blow the flies away. They would have used bounties on flies if they had thought of it. Yet somehow, the fly population never dropped a bit, as the flies continued to breed in the giant pools of chicken poop.

Killing the rats won't help. Provide bounties to whoever gets rid of what they eat.


Or to what eats them. Don't know how well they'd work in the manure pit situation, but various kinds of "Fly Predators" (I think that may be a trademark) do work quite well around barns & corrals.

Back to the original article: I can't help but wonder how they manage to effectively give away owls.


I guess they haven't read Terry Pratchett. Or maybe they have - is there already a tax on rat farms?


Here in South Louisiana, the state and local gov did the same thing for the exploding nutria population in the swamps...only it was $5 per nutria tail delivered to collection sites instead of a cell phone. Here's the link:



I remember several years ago, when I was living in Vietnam, a story similar to this. Seems that in the north, near the border with China, many Vietnamese farmers were selling cats and snakes to Chinese buyers, because cats and snakes were considered delicacies and were suddenly growing in popularity. Farmers made lots of $$ with this practice, and all was well until they discovered that, because they were selling the only major predators of the local rat population, rats increased at a frightening rate, eating all the rice the farmers were producing. The province governments, in their desire to curb the rat population explosion, began offering bounties on each rat killed. The farmer would get a small amount (may 1000 VN dong - at the time about 30 cents) for each rat tail brought in. This worked well for awhile, but some provinces found that more rats were being killed on other provinces than in their own. So these provinces upped the bounty. So a black market sprang up in rat tails - people would buy rat tails from farmers at a premium in province A, pack them all up and truck them en masse to
province B, where the price was say twice as much as in A. The farmers made out well, the middlemen made out like bandits and the government lost. Eventually, rats and rice stabilized and the program was, mercifully, ended.



I heard the other day that Los Angeles is going to ban pet stores from selling "farmed" puppies. They'll only be able to sell previously owned dogs, aka adoptions. Now let's all find the new puppy stores that'll be setting up shop on the edge of L.A.

Enter your name...

LA isn't banning all sales of puppies, just puppies being sold through middlemen (e.g., retail stores). You can buy as many puppies directly from breeders as you want.

Enter your name...

If you did this for a very brief time period, then you should be able to eliminate the breeding problem. Rat pregnancies can start at the age of 5 weeks, and each one lasts for 3 weeks. If I were them, I'd run the program for one month (perhaps one month per year) and definitely not for more than 3 months. After 3 months, I think you'll see a sharp rise in the number of farmed rats.


Do the owls get cell phones, too? Haw-haw!

$5 per nutria tail sounds high, I must read about how that went...

Wayne Yuen

Well, it depends on what kind of costs are associated with the Cell Phone right? I mean if people get a free cell phone, but the phone is inoperable without a plan of some sort, then the government is getting work done (fewer rats) with a promotion that costs people money (subscription to the phone company's plan).

I suppose there is some value in the phone... They can be sold or recycled. But would that be enough to make up for the costs of breeding 60 rats? Probably not.

See in the Cobra effect, the costs of farming was always lower than what the market was paying for the rats (or pig tails, or cobras, etc). But if they make the number higher, then the less likely it is going to be efficient enough to farm rats. But it might make it better for people to catch them, in passive ways, like traps or such, and pool them together to get a phone. 60 rats is far different a cost, than just showing up with one thing and getting paid for that one thing.

I don't know how ubiquitous phones are in india either... But if they are common, then we're not really offering anything of real value for the dead rats.


Charles L.

This will only occur if, going back to Micro101, AVC>MR, that is, the cost of growing 60 rats is less than the payout of one cellphone. I am not an expert on the South African economy, but I would reason this is not the case. Owning a rat farm would have little overhead but take up a ton of time and probably be very disgusting, at least to farm them in any noticeable quantity. As rats become scarcer, this might happen, but for the moment it would seem as if this plan is working.
I think it's good to bear in mind that while government incentive programs often have nasty side effects, they can also have very positive ones, which is why people set them up in the first place. The cobra effect is a hyperbole of a larger truth. Not all such programs end in masses of cobras swarming major cities, thankfully.