It's been a long time since I read Twenty Thousand Leagues Under the Sea, but one of the things that struck me at the time was how concerned the narrator was with how everything tasted. It was released 10 years after On the Origin of Species, so I imagine we had yet to develop a food supply stable and generous enough that most people would be happy to let all that good protein just keep wandering around in the wilderness. As the line goes, "If God did not intend for us to eat animals, then why did he make them out of meat?"