As part of its ongoing efforts to promote every single Pokémon out there, The Pokémon Company has shared special content dedicated to Yamper:
Did you know? This Pokémon is very popular as a herding dog in the Galar region. As it runs, it generates electricity from the base of its tail. This gluttonous Pokémon only assists people with their work because it wants treats. As it runs, it crackles with electricity.
Source: The Pokémon Company