Grookey's struggle for survival does not end upon evolution, but it does become easier, for their larger bodies and thicker leaf coats allow them to venture out of their warm, temperate homes. Darumaka fossils preserved in ice almost invariably come with worn grooves atop their heads that testify to their repeated use as Thwackey drums. Evidently, this relationship was symbiotic, not parasitic; the grooves usually appear shaped to match two particular twigs, so Thwackey/Darumaka pairs remained attached for a long time (perhaps even until evolution), but it is not entirely clear what either pokemon gained. Some imagine that the loud, painful noise of Thwackey drumming lured pokemon like Snorunt or Snom out of the snow to be hunted, but others have seen it as a pokemon analogy to busking, with both drummer and drum awarded with food by other pokemon who listened to the performance.
There are trees in Galar older than human habitation, with strange carvings and absent branches which bear witness to the presence of these ancient pokemon. Early humans in Galar (and to its west) did carve writing into trees, but the earliest layer of this script predates humanity altogether. We cannot be sure if they mark warnings or hunting grounds, boasts or territorial boundaries, but the thickness of the inscriptions clearly resembles that of a Thwackey stick. Thwackey even appear to have used their sticks to manipulate food – a custom always rare among humans in Galar. Yet Galarian sailors and their Thwackey pets made this exceptionally popular in Ransei.
With analogues to music, writing, and even cutlery, it is common in modern fiction to imagine Thwackey as an incipient rival to humanity. But this is not the case. Thwackey populations were in decline long before human settlement of Galar, and they survive today only inside pokeballs.