Pokémon Fun Fact: For Poliwag, swimming is easier than walking. The swirl pattern on its belly is actually part of the Pokémon’s innards showing through the skin

As part of its ongoing efforts to promote every single Pokémon out there, The Pokémon Company has shared special content dedicated to Poliwag:

Did you know? Despite the danger, it wants to come up on land. So it does its best to waddle along, but when an enemy finds it, it rushes back to the water. The direction of the swirl on their stomachs differs depending on where they live. Poliwag aficionados can tell them apart at a glance.

Source: The Pokémon Company