There is a great die-off under way, one that may justly be compared to the disappearance of dinosaurs at the end of the Cretaceous, or the sudden downfall of so many great mammals at the beginning of the Holocene. But how far can such a comparison really take us in assessing the present moment? The hard data tell us that what is happening to animals right now is part of the same broad historical process that has swept up humans: We are all being homogenized, subjected to uniform standards, domesticated. A curiosity that might help to drive this home: At present, the total biomass of mammals raised for food vastly exceeds the biomass of all mammalian wildlife on the planet (it also exceeds that of the human species itself). This was certainly not the case 10,000 or so years ago, at the dawn of the age of pastoralism.