Why are all the region Pokedexes different from each other?

Question

Why are some Pokedexes different than other in different regions if they are the same invention?

Comments

It's kind of strange when you think about it. The Pokedex already knows all the Pokemon's information... but it only fills it in when you catch a Pokemon.

---

Well, for the game...
In the Anime, Pokedex is all-knowing and actually DOES things...
In the game, it's basically a piece of metal that is being held back :P

---

Thank you both of you!

Answer 1

Because thats the model they came in, sometimes adding new features to the pokedex. All Cell Phones are basically the same but they come in all different shapes and forms.

Answer 2

Well, it's kind of like technology today. Every time you beat the Elite 4, your pokedex gets up-graded to the National Dex, which is basically the up-to-date version, meaning that the data for the pokedex numbers may change.