>>34338065All Pokemon possess complex emotions that require higher reasoning. Pokemon have been shown and stated again and again to work alongside humans on equal footing together and autonomously, which again requires higher intelligence to understand what they're doing. Ghetsis noted that your Pokeballs were shaking in rage at his words and actions, confirming that Pokemon understand complex sentences, not just move commands.
All these things are way above animal reasoning, Pokemon are clearly sapients.