. But, people being as they are, a great deal of medieval thought went into exactly what counted as "meat" and "not-meat," especially during the month-long fasting seasons of Lent and Advent. Fish didn't count as meat. Barnacle goose was also considered not meat, because it had scaly webbed feet and (supposedly) gave birth in the water. A similar argument applied to beavers: also not meat. (This isn't just a historic curiosity. Even today, Detroit Catholics are permitted to eat muskrat during fast days on the basis of a missionary's ruling from the 1700s.) Some French monasteries served rabbit fetuses, not deemed meat because they were swimming in amniotic fluid. (Really: I'm not making any of this up.) St. Thomas Aquinas declared chicken to be of aquatic origin—whatever that means—and not meat. Some bishops went further, declaring that, because they are not quadrupeds, all fowl is fair game (so to speak).