How Many Resources are Required to Feed 1 Million Soldiers?

Question

Question

I have a 1 million strong army of humanoid cat people called Felinus. Assuming they have similar metabolism what is the minimum amount of food (in metric tons) they would have to plunder from the country side to stay alive and in peek fighting condition?

Note that, like my linked question, they are using a medieval tech level.

Linked:

How to Escape an Impossible Situation Using Magic?

How to Defeat a Nature Mage?

How Do I Draw the Elves into the War?

How to Escape a Horde of Worms Using Magic with Minimal Injury?

Edit:

I felt compelled to say that they are not expecting re-supply since their homeland is on the other side of a desert larger than two Sahara Deserts placed next to each other.

Answer 1

According to this site:

Alexander's army of 65,000 men required 195,000 pounds of grain and 325,000 pounds of water to sustain it for a single day!

So, using the same estimates you will need 3,000,000 pounds (1,500 tons) of grain and 5,000,000 pounds (2500 tons) of water, per day.

They will need to harvest grain from about 1,250 acres of land to plunder that much grain, that's about two square miles. However this only provides the bare minimum for survival. They'll need twice as much to be strong and healthy warriors.

Answer 2

I know you said that they aren't strict carnivores, but if you wanted to look at how livestock can provide the calories needed, here you go.

1 kg of meat will provide between 2100-2300 calories (specific amounts depend on the type/cut of meat. This is looking at beef, pork, and chicken). According to this website, an average cow provides 530 lbs of usable meat. That's about 240 kg of beef. Let's round up to 250 kg, to account for parts of the cow that most people now aren't willing to eat, but that your soldiers might (brain/eyes/etc).

Assuming that the soldier needs about 2300 calories for a day (this is probably low), one cow will feed 250 soldiers for one day. That means 4,000 cows ought to feed your whole army per day.

One hog should provide about 75 kg of meat. So you'd need about 13,000 hogs per day.

A chicken provides about 2.5 kg of meat. You'd need about 400,000 chickens.

For the sake of this example, if you were to feed your whole army for a 3 month campaign only on live cattle that they bring along, they'd need 202,105 acres of grazing land. Formula came from here. Alternatively, if you were to bring along the fodder yourself (like grain and alfafa), you'd need 9,600 tons of it.

I'm not necessarily endorsing this solution, but if you had the land you could do it...but ideally, your army will take along with it some mix of livestock, preserved meats, vegetables, grains, as well as eat whatever they can hunt/forage/pillage.

I know these figures, as well as the figures that Samuel provided, sound ridiculously high. But considering your army is so large, the population of the empire must be enormous. If you scale everything up, including farmland and livestock necessary in order to sustain this population, then this isn't out of the question. Also, I'm assuming your entire army isn't going to be in all the same place at once. If they're divided up into several smaller companies (this is very much recommended), fighting on different fronts, then it's not completely unreasonable to imagine them hauling around the food they need.

Bonus: animal by-products. I haven't taken into account milk from cows, or eggs from hens, or all the broth you could make from their bones. But assuming your 400,000 chickens lay 400,000 eggs, you could feed about 13,000 soldiers just from their eggs alone.

If your 4,000 cows are producing, let's say, 6 gallons of milk per day, you could feed about 27,000 soldiers from the milk/cream/butter from the cows.

Answer 3

I question whether a carnivorous race could even have a million man army. Carnivores need herbivores to live on, and a lot of them. A million man army would have at least 5-8 million dependents at home, and would have to raise many times that number of cows or other food animals to live on...and crops or fodder for all those animals. Carnivores can't pack themselves together like humans can.

It just isn't possible.

Answer 4

If this is related to the same setup that I saw earlier, there may be a relatively easy handwave. Forgive me if you have already thought of this, but isn't your mage a nature wizard with the power to create nearly unlimited plant growth if there is sufficient water, etc.? If that is the case, assuming sufficiently wet land (lots of rivers and so forth, your mage could probably produce enough food to feed a very large army, once your Felinus are across the desert. There are omnivorous, after all. In addition, if he can control the minds of most non-human living things, perhaps he can draw out many animals. However, this would only work for a short time. Heavy use would deplete the water and nutrients from an area, just as conventional agriculture does. However, your mage is presumably evil, so perhaps the eventual fate of the Felinus does not concern him.

As others have mentioned, getting the million-cat army across the desert without heavy casualties would be next to impossible. However, I see a possible solution. The mage is clearly ruthless if he is willing to make an entire race march to its deaths--desperate, too, not to take the long way around. And after all, the best way to move anything is to get it to move itself. So why not have the mage force the cat people to cannibalize themselves as they cross the desert, thus providing meat and water in a relatively arid environment. If the cat-people are an entire race, they may have had a population much larger than 1 million. The Roman Empire, for example, may have had 100 million people at its peak. So the wizard forces 10 million cat-people to march across the desert, and they gradually cannibalize each other until only 1 million remain. Supplement this with extensive wells, and you might be able to get 1 million across the desert. Consider this: an average human has around 14 liters of extracellular fluid. The average human needs about 3 liters per day for replacement purposes, but maybe more like 5 under desert conditions. It would take a human around one hundred days to cross a 9000 km desert, walking at 5 km/hour, 16 hours per day. If they could extract all the water from the extracellular fluid of another human, they could remain perfectly healthy (barring hunger, exhaustion, or heatstroke) for perhaps 3 days. Even 9 humans would only keep them healthy for a month. Perhaps your cat people can extract intracellular water (total 40 liters or so), and maybe they can regulate their temperature well enough that heat does not change their water requirements. So reverse-decimating your cats would keep them alive long enough to cross the desert, and you might not even need to kill nine-tenths.

Honestly, wells are mostly irrelevant. Suppose you have a village. It will likely have no more than three wells. If each well has about 6000 liters (pretty generous for desert environs), then 6000 Felinus have their water needs met for a day. A (formerly) heavily populated desert would have no more than one town every 8 km, which is ridiculously well-populated. Even then, only 60,000 Felinus out of your million will have their water needs met every day.