Some Bog Butter Is Actually Animal Tallow, Not Dairy

When scientists at the University of Bristol analyzed ancient Irish bog butter, they expected to find dairy. Instead, they got a surprise. Using carbon isotope analysis on nine samples of bog butter, they discovered that six were indeed dairy products made from cow's milk. But three samples, about one-third of those tested, were something else entirely: animal tallow, likely rendered fat from animals stored for later use. This finding suggests ancient people used bogs as preservation sites for various fats, not just butter. The tallow would have been valuable for cooking, lighting lamps, and waterproofing. Like dairy butter, these animal fats were buried in the cool, oxygen-poor, acidic environment of peat bogs, which acted as a natural refrigerator. The discovery reveals that our ancestors were more resourceful than we imagined, using the same preservation technique for multiple types of fat.