The Alolan forms are something ‘brand new’ for most of the Pokemon Go player base. Some players already know important things regarding Alolan forms, and some don’t, so I dug a little bit deeper, and here is what you should know.
Alolan forms are just an alternate version of the same Pokémon which are supposed to represent Pokémon of the same species that evolved differently for geographical reasons (such as a normal red fox vs. a snowy winter fox).
They are called Alolan forms because they come from the Alolan region in the main series games (just like the current newest release set in Pokémon GO comes from the Hoenn region).
They resemble the original form of the Pokémon, but they have a different typing and stats, and as a result they have a different appearance that resembles their new typing better.
They are NOT a different Pokémon nor are they like a shiny — in the Alolan region, this is just what all Pokémon of that species look like.
We can expect these Alolan versions to learn different moves, be a different type, and have different stats, and therefore have a different max CP than their non-Alolan comrades.
They will almost definitely have the same entry in the Pokédex but with a button for their Alolan form, just like Castform. It would be strange for Niantic to not do it this way.
In the Alolan region, Vulpix & Ninetails have evolved as winter foxes because they reside in a snowy mountain. As a result, Alolan Vulpix is an Ice type while Alolan Ninetails is Ice/Fairy, and they learn appropriate moves for those types instead of Fire moves.
In the Alolan region, Rattata and Raticate are nocturnal, so they are both Dark/Normal instead of pure Normal.
Alolan Exeggutor’s neck is hilariously long, resembling a true palm tree, and it becomes Grass/Dragon.
Pokémon with Alolan forms: Rattata & Raticate, Raichu, Sandshrew & Sandslash, Vulpix & Ninetails, Diglett & Dugtrio, Meowth & Persian, entire Geodude line, Grimer & Muk, Exeggutor, and Marowak.
Alolan forms were introduced in Pokemon Sun and Moon.
The following Pokemon can evolve into Alolan forms from their natural form, that is to say, a Pikachu can evolve into both a regular Raichu or an Alolan Raichu based on different things, I’m not sure how Pokemon Go will handle this.
The following pokemon have their own base form Alolan forms that must be caught to evolve into their higher Alolan forms. Thus an Alolan Rattata cannot evolve into a normal Raticate, it can only evolve into an Alolan Raticate.
Q: Are they evolutions for existing Pokemon?
A: Yes – for only Gen I Pokemon only. Here’s the list:
Q: Do you have to find an “Alola X” to evolve it into “Alola Y?”
A: All the others change the whole evolution line: for example Alolan Vulpix evolves into Alolan Ninetales, while normal Vulpix evolves into normal Ninetales. Regular Pikachu can become a regular Raichu normally, while it only becomes an Alolan Raichu in the Sun/Moon/Ultra Sun/Ultra Moon games, while only Alolan Vulpix/Geodude/Diglett/Sandshrew become their Alolan counterparts. However, we don’t know how these evolutions will translate to Pokemon Go.
Q: Do they work like shinies?
A: No, basically they are what they normally look like in the Alola region: for example, all Vulpix caught in the Alola region will be in their Alolan form.
If you have any other questions, please write them in the comment section below, and I will try to answer them. Have in mind that Alolan forms are coming in the following weeks, so there will be a lot of new info coming.