>>32486268The anime was originally supposed to take place on a futuristic Earth. According to two supplementary books made by Takeshi Shudo, Pokémon popped up on Earth one day. They eventually began replacing animals however some animals still survived. This explains early episodes where real-world countries exist and animals are shown. The original plot for the third film was even going to be about what happened to real-world animals according to Word of God.
tl;dr this Pokemon is known as "Early Installment Weirdness", and it is one that is featured in many shows, though probably most prominently in Pokemon.
