Ancient Mexico, like most forest-invested New World tropics, was deficient in the kind of large game that flourished on the plains of Africa and Asia.... The situation was partially relieved by cannibalizing the victims of human sacrifice.... The [Aztec] priesthood... sanctified it... immediately after their hearts had been cut out, the victims were systematically butchered like animals and their parts distributed and eaten.
On Human Nature (1978) - Ch.4 Emergence