>>47113296The same reason they put gastrodon on the year of the bull artwork.
There wasn't enough actual rats/bulls, so they went and stretched to layman's terms to fill it up. If pokemon was in the west, or if there was a manatee pokemon, a manatee might have ended up on this years.
If you use this promo not meant to be anything but fun art as evidence, understand you're also saying they consider gastrodon a bull. I know the slug is called a sea cow, but that's the point. That doesn't make it a bovid.