First of all the catastrophe that biblical scholars referred to as being about 14,000ya was probably the same catastrophe, that Sunken Civ has frequently posted the book by Firestone et al to illustrate. That event destroyed the Clovis culture, and killed so many large mammals that only small numbers survived for long afterward and probably died off from having too few members left to breed. About a century before Cortez showed up in Mexico, a chief advisor told his ruler that they should make their neighbors be their bread. Thus wars were fought against neighboring tribes and captive warriors “honored” by being sacrificed ritually and then eaten. The tortilla is the “bread” of Mexico, and in Aztec (Nahuatl) is tlascalli. Cortez met a neighboring tribe called the Tlascallans who contributed thousands of warriors to help Cortez cut off the “bread” supply. I don’t know which came first, the name for bread or the name for the tribe. In addition Aztecs ate turkey (guajalote), ducks, fish, frogs, and bugs.
The range for coyote reaches the Panama Canal today; that was considered a game animal as well as whatever domesticated dogs were around. The food supply and water supply across a wide band tended (still does) to restrict the distribution of bear.
As glee' noted, the Aztecs hit the all-time height (even in the Americas) for human sacrifice. There was a long structure in the plaza in front of the big pyramid in Tenochtitlan, the Aztec word for it meant "the corncrib" -- the Spanish were appalled that it was chock-a-block full of defleshed human remains in the 100s of 1000s. The Aztecs called their predation "Flower Wars", and as glee' noted, there was no lack of native allies to resist the Aztecs when Cortez first arrived.
During the flight out of the city and back to their landing site (Veracruz, I believe), expedition member Bernal Diaz wrote that the towns they'd previously passed through were emptied out, which apparently was a consequence of the incidental introduction of diseases new to the local populations.