Thick Fat
The Pokémon is protected by a layer of thick fat, which halves the damage taken from Fire- and Ice-type moves.
Hydration
Heals status conditions if it's raining.
It sleeps under shallow ocean waters during the day, then looks for food at night when it's colder.
It stores thermal energy in its body to fend off the cold. It swims at eight knots even in frigid waters.