>>51754723Certain animals were used because there weren't Pokemon analogues at the time. For example, there was no mongoose Pokemon yet for
>>51757723 this scene with Ekans.
Towards the end of Gen 1, Game Freak formalized a standard for its games that the anime also adopted. Specifically, no animals at all. They talk about this in their generational official lore book they release with every Gen. In ORAS, they even joked that they accidentally broke their own rule by including coral in the background.
Takeshi Shudo was the original head writer/director for the anime. He was obsessed with making Pokemon "darker" and was constantly complaining about the direction the franchise was heading after Gen 2. In his anime design documents, he claimed that there was a "dark and serious reason why animals suddenly went extinct in the Pokemon world" and he promised to reveal it in the anime in the future. He then fucking died and took the secret to his grave.
Some other facts about Shudo: he designed Lugia, strictly wanted it to be female, and when he learned it was male in the movie, it drove him into alcoholism and depression, taking hard drugs including horse tranquilizers, which contributed to his death.
