I wonder whether oak gall ink is vegan. The larvae of the gallflies (actually wasps) that grow in oak galls emerge as adults in early summer, according to the Wildlife Trust, leaving the gall mostly intact. Thus, theoretically, it should be possible to make oak gall ink without harming any animals. It would still be an animal product, but produced only from by-products of a wild animal. But then again, perhaps changes in the chemical composition of the gall throughout the larvae's development make such late-harvested galls unsuitable for ink production.