The selection of standardized ancestry feats and their specific options represent the ancestries and cultures of the Starfinder setting. With your GM's permission, you can adjust the feats and options for other settings or situations. For example, gnomes can normally select any burrowing animal for Ancestral Pest, but a settlement of gnomes on a forested moon who magically bond with squoxes could select
Ancestral Pest (squox) instead; such gnomes would be unable to select a burrowing creature like a mole for Ancestral Pest.