He dismissed any possibility that the pork taboo originated from a literal reading of the Bible, and disputed this with various arguments, noting that early Christian missionaries did not snub pork. He conceded that archaeological evidence was found of pigs being eaten in prehistoric Scotland, but suggested this might have come from pork-eating peoples living near others who did observe the taboo, or be related to ceremonial use of pigs. Later pork production was for export, not for local use, just as eels were caught to send to the English market, while they were unacceptable as food in Scotland. The taboo died out in the Lowlands earlier than in the Highlands, and by the 1800s, most crofts in the Highlands and Islands would have kept a grice.