In another thread the supposed plan to make a living out of selling cat skins was mentioned. It originated with with newspaper editor Willis Powell in 1940 as a joke.
“Glorious Opportunity to Get Rich–We are starting a cat ranch in Lacon with 100,000 cats. Each cat will average 12 kittens a year. The cat skins will sell for 30 cent each. One hundred men can skin 5,000 cats a day. We figure a daily net profit of over $10,000. Now what shall we feed the cats? We will start a rat ranch next door with 1,000,000 rats. The rats will breed 12 times faster than the cats. So we will have four rats to feed each day to each cat. Now what shall we feed the rats? We will feed the rats the carcasses of the cats after they have been skinned. Now Get This! We feed the rats to the cats and the cats to the rats and get the cat skins for nothing.”
Leaving aside the unlikelihood of finding a market for cat skins, where would this plan break down if you actually tried it? Are the reproduction figures for cats and rats accurate? Would the cats starve to death due to insufficient rat meat or would the rats starve to death first due to insufficient cat meat?
Well, OK, the problem is waste in general. Only a small fraction of the food value eaten by either rats or cats gets turned into meat. There’s a lot of waste in the system. The poop itself, of course, but a lot of energy is converted to heat to stay warm, energy to move around, etc. There’s no way to keep all of this energy in the system. (Good old entropy at work).
And since the cat skins are being removed from the system, there’s that much less edible material going back to the rats.
Dude, it is free energy. Is rat digestion 100% efficient? Is cat digestion 100% efficient? Do cats and rats create body heat which is radiated into the environment? Do they expend energy by moving about? Do they piss and shit?
Therefore, since at every stage of the process there are energy losses, the scheme violates the laws of physics.
As said above, it really is an attempt at free energy. Add to that you’re taking valuable protein out of the system in the form of pelts. Besides all the practical problems it violates basic principles of physics.
Can twelve rats grow to adulthood eating nothing but one cat? Can a cat grow to adulthood eating nothing but twelve rats? Remember, we’re not talking about the animals eating this much per day, but for an entire lifetime.
You are on to something there. You should invest in a rat and cat farm immediatly. It only takes 1 cat and 12 rats to start. You shouldn’t have any problem selling the cat skins as fertilizer or fuel, so you only need to invest the profits into buying more rats and cats until you reach the volume where you are self-sustainable, having only the cost of cat skinners and cat/rat ranchers to pay. Once you have demonstrated this perpetual motion machine’s viability, you will have an endless number of innovators who will find uses for the cat skins. Note: using slightly larger cats such as leopards, and more, or larger, rodents, you can produce fine furs that will have tremendous value. I believe all of the SDMB members would agree that you would be a fool not to jumpstart this enterprise immediatly.
I understand the basic physics and biology issues. It’s not going to be a closed system. I’m just wondering where the specific breakdown point would be. Would the cats or the rats die out first?
After 19 days you will be out of cats. They have produced any kittens yet since the gestation period is around 60 days. You have plenty of rats left, but they haven’t produced any ratlets or whatever they are because their gestation period is at least 20 days. If you are assuming some rats and cats are pregnant when you start, you’ll have to supply more information regarding the percentage of gravid animals and the ratio of sexes. You also do not include the standard for how old a cat must be before it can be skinned.
If he claims he invented it in 1940, he’s a plagiarist. The theme was covered very well (and in more detail) and with most of the same numbers by Wodehouse in Buttercup Day in 1925 (q.v.)
You guys are overanalyzing this. So I’ll break it down.
How many grams of meat does an average rat need to eat each day to survive?
How many grams of meat does an average cat need to eat each day to survive?
How many grams of meat can you get out of an average rat?
How many grams of meat can you get out of an average cat?
Every day you skin 5000 cats and feed the carcasses to the the rats.
With 1,000,000 rats, that works out to 1 carcass for each 200 rats.
If each cat weighs 10 pounds, you’d be lucky to get 5 pounds of edible protein from each carcass once you remove the bones, skin and fur.
That works out to less than 1/4 ounce of food per day for each rat.
That’s not enough food for a rat to survive on. So your entire rat population is on the road to starvation from day one. You don’t have enough employees to kill the cats fast enough.
I doubt you’d be able to keep the rats alive long enough to get your first litter.
That depends on how you interpret “One hundred men can skin 5,000 cats a day”.
If you have 100 men skin 5,000 cats a day (50 cats each) the men are skinning a little over 6 cats per hour, which is a pretty leisurely pace. You’ll gross only $1,500 when you sell them at 30 cents. Only the Enron Cat Skinning Company can show $10,000 net profit on $1,500 gross proceeds. And on day twenty, you’ll be out of cats.
Light a fire under those workers so each man is skinning 5,000 cats a day (about 1 every 6 seconds) and watch the fur fly! Now, you can net $10,000 profit on $150,000 gross per day. Well, you could if you didn’t run out of cats before the 10 o’clock coffee break.
And a real business man would find a market for rat fur. If you can sell those for 3 cents you have doubled your revenue.