What is the distinction between animals and Pokémon within universe? Granted they rarely allude to real animals in recent games, but canonically animals due exist in the Pokémon universe, so what do humans use to determine the difference between the two? Some Pokémon are pretty unremarkable and there are animals that are conversely more fantastical than Pokémon. Intelligence seems to not be a defining trait either. And I’m not really referring to game mechanics like “moves” and “abilities”, as surely a real bird can do things like peck and a real elephant could do things like stomp and tackle… heck archerfish can essentially use water gun and could probably splash which is already more moves than Delibird learns.
I… don’t like that word, “canonically.” I think Pokémon has been around long enough, spread itself across enough different media and subjected itself to enough retcons that the idea of “canon” oversimplifies to the point of meaninglessness. References to real animals almost always predate the introduction of Pokémon that would be able to supply those references – cows only exist until Miltank turns up, mongooses stop being a thing when they’re superseded by Zangoose, etc. Similarly, I don’t think there is “canonically” a place called Guyana on a continent called South America in the Pokémon world. Guyana was mentioned in a game that was made before Pokémon believed it would ever leave Japan, in a context that demanded a name recognisable as “somewhere exotic,” and the references to it were left there in a remake which, on the whole, made few substantive changes to game content. Things from the real world fill in the gaps that Pokémon hasn’t gotten around to explaining in its own way yet (or, in some cases, provide jokes that are meant for the real-world audience but shouldn’t be taken as having worldbuilding significance). References to them become rarer, and refer to less notable things, over the course of successive generations. Things that Pokémon will likely never bother to provide its own version of, because they form part of the “scenery” – plankton, small insects, plants, maybe the occasional small fish or lizard – can be treated as “real,” or “canon” if you like. Others should be treated as placeholders, to be retconned out of existence as soon as something exists to replace them.
In any case. I suspect that “Pokémon” is, in-universe, a catch-all term without a proper biological definition. It means something that can be captured, trained, and used in a battle against other Pokémon. It’s a little like the word “fish” in standard English. Basically any macroscopic animal that spends its whole life in the water can be called a “fish,” some of them are more closely related to humans than they are to other “fish,” and there is no defining set of traits that includes all “fish” but excludes all non-fish.