system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokemon] What separates normal animals from pokemon?

I'm pretty sure in season 1 of Pokemon, you see some normal animals, and fish. 

What separates those animals from pokemon? I'm pretty sure you could train a cow to tackle someone. Sure, a cow can't evolve, but what's to stop someone from putting a big old bull from a bull fight into the Pokemon league?

"Cow, use trample... No, not on the trainer! Not on me! Oh, christ, get the tranq gun!"...

Other than that I mean. But what's the difference between an animal and a pokemon?
gpt
Pokemon have within themselves a form of power known as infinity energy. This energy is what makes pokemon more than just animals, what makes them able to control the elements and allows them to evolve. 

Take a Miltank for example. It may be a "normal" type but this itself seems to be an element along the infinity spectrum. Its normal attacks carry within them some sort of extra energy, which is why moves are limited by power points. Even a simple move such as tackle is actually a way for a pokemon to channel its inner energy.

Therefore a pokemon will almost always be stronger than just a regular animal. Animals and humans (aside from say, psychics but that's a whole other thing) can only rely on their innate physical strength. A pokemon however has their physical and elemental (or special) strength to use in tandem. Thus a cow is a cow, and a rhyhorn is a rock-plated rhinoceros.