Which Pokémon leads the environmental investigation in Pokémon Pokopia?

Professor Tangrowth leads the environmental investigation in Pokémon Pokopia.

After Ditto finds its Trainer's old Pokédex and takes on a human-like form, it meets a Tangrowth known as Professor Tangrowth. This character has made it his task to study the damaged environment and investigate why humans and Pokémon disappeared.

Professor Tangrowth is a story-specific version of Tangrowth, the Grass-type Pokémon introduced in Generation IV. The professor's role connects the game's ecological mystery with its central rebuilding mechanics.

The character is easy to confuse with Professor Oak or other human Pokémon researchers. Unlike those established human professors, Professor Tangrowth is a Pokémon and is part of Pokopia's unusual post-apocalyptic setting.