In this world, magically active patches of ground later called "Aesop Domains" started to appear in the early 15th century, France being probably the first place affected. Any mammal spending a few minutes in a Domain turns into (within a few hours) a roughly human-sized and humanoid bipedal sapient - a Furry, if you will, locally called "Aesops." Although they can breed with their own kind, restraining them from breeding does not stop the number of Aesops from increasing - wherever an Aesop dies, another Domain comes into existence, and Domains cannot be eliminated once they come into existence. (The first Domain was of unknown origin - Alien Space Bats? A Wizard Did It? Who knows? - but all later ones were due to Aesop deaths.)
So, the world has had to adjust to an ever-increasing number of non-human intelligences sharing the planet with humans. This has led to not so much butterflies as Rocs, and it's surprising the world looks like OTL as much as it does. The Protestant Reformation was complicated by the arguments as to whether Aesops had souls, were just smart beasts, or were creations of the devil, which added new and exciting doctrinal disputes to have wars over. The Papacy split into Pope and anti-Pope again (for a while there were three) and hijinks ensued.
As Aesops increased in numbers, they largely replaced humans as slaves, and by modern times much of the world's labor was done by Aesops, with of course consequences in the form of revolutions, Aesop massacres, and such oddities as socialized slave ownership. On the positive side, human racism, faced with a truly other other, receded, and inter-human wars became somewhat rarer.
As of 1994, there hasn't been a truly major war in over a century (the Dozen Wars of the period 1932-1948 were something of a damp squib, killing under a million people total), but the situation is becoming critical. The Aesop population is now matching that of humans, and global food supplies are increasingly stretched, and new Aesops show up every time a mouse runs over a Domain. Technology is little more advanced than our world's WWI era, greater religious violence and an increasing over-abundance of labor having slowed scientific progress. (Supernatural thinking is a lot more prevalent even in developed countries, since Aesop Domains and Aesop transformations from animal to Furry form have nothing to do with physics and biology as they are known). Many countries which use a lot of Aesop labor are trying to wean themselves off it, while countries with fewer numbers of Aesops are talking about eliminating them from human society entirely: outright genocide is still frowned on, but there is a lot of heated talk, especially in the Aesop-crowded regions of western Eurasia.
Africa, with little foreign need for human slave labor (and therefore no Slave Trade issue) and an even harsher disease regime, has seen little outside penetration of the interior, with the Arabs (who are Very Determined to spread proper Islamic orthodoxy) being the main exception, and even they mainly work through the more disease-resistant black Africans and racially mixed coastal Swahili. This may change, as genuinely effective tropical medicine is finally being developed.
Brazil, the world's most advanced nation, hopes to use Science to control the Aesop population non-violently and create a state of peaceful co-existence (well, one where Aesops accept humanity's benificent leadership. They're not perfect goodies). Their north American rival, the Avalon Confederation, sees this as a "betrayal of mankind" which will lead to all sorts of perverted terrors and armies of Aesops eventually marching north: the current Avalonian president, who has promised taking a "stand for humanity" and "against the growing Aesop threat", is making a great deal of propaganda hay.
This will probably not end well.
That being said, Aesop domains only transform mammals -- other animals are unaffected, so, while most environments are going to take severe beatings at best, normal animals (non-mammalian ones, anyway) will survive. In the short term, I imagine this will lead to a world highly dependent on seafood and poultry to keep humans, omnivorous Aesops and carnivorous Aesops fed. In the long term, it might very well lead to a world where birds end up taking over the ecological roles left behind by "wild" mammals.
An interesting idea. Though the way it's set up - ANY mammal spending even a few minutes inside a domain makes them an anthro, and any anthro dying creates a new domain - means that eventually all mammals, everywhere, will be anthro. Perhaps something will change before that happens, but I imagine the ecology would be devastated if it's not. And, of course, society. But society can change; the ecology, being largely unguided, would take a long time to recover, and it'd never return to what we consider normal.
That wouldn't happen for a while, but it's coming. It's unclear how large these domains are, but the description mentions that the number of anthros is "matching that of humans," after all, and even if we assume that there are fewer humans there than here, that's still probably a few billion. When those billions die, billions of new domains will form, and tens if not hundreds of billions of new anthros will be generated within them. Another generation or two may be all that's left before the ecology outright crashes. Society is likely to undergo some major upheavals even sooner.
Interesting world. Glad I don't live there.
Thanjavur Kingdom was originally named Pandya Kingdom, after an old dynasty, but I asked Bruce to change it to avoid confusion with pandas.
The Arabian Empire's conquest of Persia had about as may casualties as the other eleven of the Dozen Wars combined.
The territories along the west coast of Brasil going to the north are bilingual in the same way Quebec is bilingual in Homeline...annoyingly Spanish vs Portuguese (when I was in ham radio, I heard a Canadian ham say he wished the Francophones would leave Canada and move to a place with a MUCH hotter climate).
Here is the Pyramid article:
The Aesops don't look like the thing on the right hand side (which looks like Lon Chaney Jr on a bad hair day). If that is supposed to be a canine, it would look like a Vargr from Traveler. And I don't know WHAT that dragon/gryphon/whatchamacallit by the title is supposed to be.
Only one Aesop domain formed randomly, probably in France (or maybe England) around 1400. All the Aesop domains since are the death site of an Aesop. The rest of your conclusions are correct.
The idea came to me in a dream where Alvin the Chipmunk died in my bedroom and left an Aesop domain. I think my subconscious was regurgitating the sowander from Garry Kilworth's Hunter's Moon/The Foxes of Firstdark.
On the old Alternate History forum, I extrapolated the world to c2003 (now deleted). In 2000 on a wave of Millennialism, Avalon elected an even more extreme President (they hold their elections every six years) who emulated TL-191 and did a Jake Farnsworth on Brasil and as many Aesop as he could reach. There was a Hemispheric War even worse than our World Wars.
Funny thing...I recall one commentator who asked (hopefully) if insects were affected by Aesop domains. Insects? INSECTS! Do you know how many insects are in a square mile of land? The planet would end up looking like a peach pit in the middle of a pulp of human sized insectoids. Septillions of insectoids.
The reason the Arabian Empire is the only significant outside influence on Africa is because they are fanatics. They are the only ones crazy enough to go there, as malaria in Aesop is more virulent a strain than ours, and they don't even have quinine yet.
When I refer to it, I say "butterflies as big as jumbo jets", but I like Rocs better. I agree, it is too parallel for such a large divergence. But I was writing for the GURPS IW campaign, and they are full of things like worlds where Alexander's Empire still rules the world and Jesus of Nazareth was never born, but Adolf Schicklgruber was a famous artist and convert to Judaism.
Glad you enjoy it (when I sent it in, Steve Jackson said "SHEESH, another one for the Furries!" but he published it). My sole paid work ($64.32 IIRC).
One, Aesop domains sometimes form randomly, or at least for no reason that anyone's able to detect at the current tech level.
Two, an Aesop domain forms wherever one or more Aesops die.
Three, Aesop domains never go away. Regular land can become an Aesop domain, but an Aesop domain cannot become regular land.
Four, any mammal that spends more than an hour or two in an Aesop domain becomes an Aesop itself.
Five, Aesops can breed true with conspecifics and can thus increase their population independently of Aesop domains.
Thus, the amount of the Earth's surface covered by Aesop domains can only increase but not decrease; also, the number of Aesops, both in absolute terms and relative to normal mammals, is also steadily increasing. The absolute and relative amounts of non-Aesop mammals can also be presumed to decrease over time, since the amount of land area in which they will not be turned into Aesops is evidently on the decrease.
Presumably, there will be a time at some point in the future where a plurality, and eventually a majority, of Earth's surface will be covered by Aesop domains; thus, there will also come a time when the population of "wild-type" mammals will have fallen far beyond what they used to be, as the amount of land capable of hosting them without transformation will have sharply decreased; eventually, most mammals in existence will presumably be bipedal sapients.
This will all likely take an extremely long amount of time to happen, but from what I see it's a process that can be slowed but cannot be halted.
Even ignoring the social issues already discussed, I foresee serious ecological collapses looming in the eventual future.