I'm a bit under the weather and it's getting in the way of getting The Very Soil done, I'm afraid. Please accept this nonsense instead, and The Very Soil will go up Thursday. Sorry, guess I'm not all that clever after all.
What, asked the Equestria Daily on Twitter the other day, is the population of Equestria?
Let's start with a simpler question: What's the population of Ponyville? There's a couple of different clues we can use. First, we can use turnout for major town events like Winter Wrap-Up or the sale of Apple Family Cider to make an estimate. Twenty percent turnout is pretty good for a major event (that is, ten percent of the town population showing up), and there appear to be a couple of hundred ponies in line for cider or working on Winter Wrap-Up, so that gives an estimate of 1,000 to 1,500 inhabitants.
Alternatively, there are about 20 ponies in Apple Bloom's class, all about the same age. If we assume that ponies spend 12 years in school just as we do, that gives 240 school-age foals in Ponyville. School-age children make up about 16 percent of the population in the U.S., and if we assume the same of Ponyville, that gives us 1,500 total Ponyville residents.
Can we make that assumption, though? I'd argue yes--many of the place names in Equestria, and the presence of Appleloosa and Manehattan as locations visited in the show, suggest that Equestria is at least in part a fantasyland version of the U.S.
This then gives us the key to estimating the population; if we can find a U.S. city broadly equivalent to Ponyville, we can compare its population to Ponyville and extrapolate from that to Equestria as a whole. After a bit of research, I've chosen Butler, Pennsylvania as the closest equivalent to Ponyville--it is a small farming community in a forested area, not too far from mountains, and has a signature product that put it on the map. Butler has a population of about 13,000, but we're estimating, so let's call that ten times the population of Ponyville.
If Equestria is a fantasyland version of the U.S., it would imply that the relationship between Ponyville and its nearest American equivalent mirrors that between Equestria and the U.S., meaning Equestria has about one-tenth the U.S. population, or a bit over 30 million. For comparison, that's about the population of Peru and a bit less than the population of Canada.
We can in turn use this to estimate the size of Equestria by making some assumptions regarding agriculture. Approximately 40 percent of the land area of the U.S. is dedicated to food production, which is to say about 1.5 million square miles to support 300 million people. However, ponies do not need 150,000 square miles of farmland to support their population. First of all, Equestrian ponies are small, about the size of a border collie, which ways about one-third of a typical adult human. Since the amount of food a mammal needs to eat is mostly a function of its size and metabolism, and the ponies appear to have a similar metabolism to humans (they eat three meals a day like we do, and the meals appear to be about the same size relative to ponies as our meals are relative to us), so we can conclude ponies only need 50,000 square miles.
Or we would be able to, if not for two wrinkles: pegasus weather-control and the subtle magic of earth ponies. How much of an impact this has (especially since ponies lack the high-output, often environmentally destructive technology of industrialized farming, and it's hard to gauge to what degree that balances out their magic and super-special talents) is difficult to guess, so let's pretend they're twice as efficient, and therefore only need 25,000 square miles of farmland.
Going back to that 40 percent farmland figure, this gives a total size of 62,500 square miles, a bit smaller than Latvia. No wonder they seem able to get anywhere in the country via train ride one commercial break long!
That packs one-tenth the U.S. population into one-twentieth the area, but remember, ponies are smaller than humans and about a third of ponies don't even live on the ground, so compared to their size each pony actually has more space than an average American--and keep in mind, the U.S. is only at about the 25th percentile in population density: Ireland is twice as dense, Micronesia five times as dense, and Japan more than ten times as dense. In terms of population density, Equestria is thus comparable to Ireland.